9.4 Prescriptive Approach and Mandatory Requirements

The prescriptive requirements apply to additions in the same way they apply to new buildings and must be documented on the CF1R-ADD-01 or CF1R-NCB-01 Form.

Except as noted, all applicable prescriptive requirements for additions must be met when using the prescriptive approach. Otherwise, the building must comply using the performance approach.

For prescriptive additions, a certificate of compliance (CF1R-ADD-01 or CF1R-NCB-01) form must be completed and submitted for permit. If any mandatory or prescriptive features require HERS verification or testing or both, the certificate of compliance for the project must be completed and registered online with a HERS Provider before submittal to the enforcement agency. Refer to Section 2.2.2 and Section 2.5.

9.4.1 Prescriptive Additions

There are three prescriptive paths available for additions based on the total conditioned floor area (CFA) of the addition. The total CFA of the addition may include floor areas representing several physically separate additions to the building under the same permit. Table 9-2 through Table 9-6 summarize the key features of the prescriptive envelope requirements for the three prescriptive addition options in §150.2(a)1.

1. Total glazing area up to 75 ft² or 30 percent of the conditioned floor area, whichever is greater.

2. Total glazing area maximum for west-facing glazing is 60 ft² or 5 percent in Climate Zones 2, 4, and 6-15.

5. Ceiling insulation of R-38 in Climate Zones 1,2,4 and 8-16, or R-30 in Climate Zones 3 and 5-7.

7. Extensions of existing wood-framed walls (Figure 9-1) may retain the dimensions of the existing walls and require the following cavity insulation:

8. Existing wood-framed walls where existing exterior siding (or cladding) will not be removed, do not need continuous insulation, and require only cavity insulation:

1. Total glazing area up to 120 ft² or 25 percent of the conditioned floor area.

2. Total glazing area maximum for west-facing glazing is 60 ft² or 5 percent in Climate Zones 2, 4, and 6-15.

5. Ceiling insulation of R-38 in Climate Zones 1,2,4, and 8-16 or R-30 in Climate Zones 3 and 5-7.

7. Extensions of existing wood-framed walls may retain the dimensions of the existing walls and require the following cavity insulation:

8. Existing wood-framed walls, where existing exterior siding (or cladding) will not be removed, do not need continuous insulation, and require only cavity insulation:

1. Total glazing area up to 175 ft² or 20 percent of the conditioned floor area, whichever is greater.

2. Total glazing area maximum for west-facing glazing is 70 ft² or 5 percent in Climate Zones 2, 4, and 6-15.

3. Extensions of existing wood-framed walls may retain the dimensions of the existing walls and require the following cavity insulation:

4. Existing wood-framed walls, where existing exterior siding (or cladding) will not be removed, do not need continuous insulation, and require only cavity insulation:

6. When an addition greater than 700 ft² is an existing unconditioned space converted to conditioned space, the QII requirements do not include:

Example 9-9

Question:

A small addition of 75 ft² is planned for a house in climate zone 7. An existing porch is being enclosed by extending the existing 2x4 wood-framed walls. The existing heating and air-conditioning system will serve the new conditioned space, including an extension of less than 25 linear feet of new ducts. The contractor wants to follow the prescriptive requirements. What requirements apply?

Answer:

Because the addition is smaller than 400 ft², the total fenestration area is limited to a maximum of 75 ft², and west-facing fenestration area is limited to 60 ft². The fenestration must meet the prescriptive U-factor and SHGC requirements of Table 150.1-A, which are a maximum U-factor of 0.30 and a maximum SHGC of 0.23 in climate zone 7.

In climate zone 7, for an addition of this size, insulation requirements are R-30 ceiling insulation with radiant barrier in a ventilated attic, and R-19 floor insulation. The new 2x4 walls that are extensions of existing walls (Figure 9-1), require only R-15 cavity insulation. Any walls that are not extensions must have a maximum 0.065 U-factor. This can be achieved with a 2x4 wood-framed wall with R-15 cavity and R-4 continuous insulation. Since the addition is less than 300 ft² there is no cool roof requirement.

Since existing heating and cooling equipment is used, that equipment does not have to meet the mandatory equipment efficiency requirements. Duct sealing requirements apply regardless of the length of ductwork extended to serve the addition. The existing duct system must be sealed and tested to have no more than 10 percent total leakage or 7 percent leakage to outside. Duct insulation requirements apply to any new ducts, which is R-6.0 minimum in unconditioned space, and the duct system must be sealed (Exception 4 to §§150.2(a)). All other applicable mandatory requirements in §150.0(m) must be met.

Example 9-10

Question:

If I remove a window from the existing house and reuse this window in an addition to that house, does the relocated window have to meet the prescriptive requirements?

Answer:

Yes, if using prescriptive compliance, in which case the relocated window must be treated as a new window and must meet the U-factor and SHGC requirements of §150.1(c)3. If you use this existing window in the addition, you must use the actual or default U-factor and SHGC of the window in showing compliance. Therefore, meeting the prescriptive requirements may not be possible, and performance compliance may be the only option. Window certification and labeling requirements of §110.6(a) do not apply to existing used windows.

Relocated windows must also meet the maximum area-weighted average U-factor in §150.0(q) with the EXCEPTION of up to 10 ft² or 0.5 percent of conditioned floor area, whichever is greater.

Example 9-11

Question:

For an addition alone, do the refrigerant charge requirements in §150.1(c)7A and fan airflow and watt draw measurements in §150.0(m)13 need to be met for existing air conditioners serving an addition?

Answer:

If existing equipment is used to serve the addition, the refrigerant charge, airflow, and watt draw requirements do not need to be met as specified by Exception 3 to §150.2(a). However, if the existing duct system is extended to serve the addition it must meet the duct insulation requirements and duct sealing requirements must be met (Exception 4 to §§150.2(a)). . New ducts in unconditioned space also shall meet the prescriptive duct insulation requirements per §150.2(b)1Di.

If a new system is installed to serve the addition, it must meet all the requirements for space conditioning in a new home which includes prescriptive refrigerant charge verification in Climate Zones 2 and 8-15 and mandatory fan airflow and watt draw testing in all climate zones. The one exception is that prescriptively the new systems may be either a heat pump or gas heating system.

Component	Additions ≤ 400 ft²	Additions > 400 and ≤700 ft²	Additions > 700 ft₂
Roof/Ceiling Insulation	CZ 1, 2, 4, 8-16: R-38 CZ 3, 5-7: R-30	Same as ≤ 400 ft²	Option B or C [C = require ducts and air handler to be in conditioned space] (see Table 9-3 below).
Roof Products (Cool Roof)	Steep Slope (≥2:12): CZ10-15: Reflectance = 0.20 and Emittance = 0.75; or SRI = 16 Low-Sloped (<2:12): CZ`13&15: Reflectance = 0.63 and Emittance = 0.75; or SRI = 75 Exception: Additions ≤ 300 ft² exempt from cool roof requirements	Same as ≤ 400 ft²	Steep-Sloped (≥2:12): CZ10-15: Reflectance = 0.20 and Emittance = 0.75; or SRI = 16 Low-Sloped (<2:12) CZ 13&15: Reflectance = 0.63 and Emittance = 0.75; or SRI = 75
Radiant barrier above attic	CZ 2-15: Radiant barrier above attic spaces	Same as ≤ 400 ft²	CZ 2-15: Radiant barrier above attic spaces except when complying with Option B (see §150.1(c)2)

Figure 9-4: Ventilated Attic Prescriptive Compliance Choices for Additions >700 ft²

Table 9-5: Envelope Wall/Floor Insulation Requirements for Prescriptive Additions

Component	Additions ≤ 400 ft²	Additions > 400 and ≤700 ft2	Additions > 700 ft2
Exterior framed wall¹ insulation	CZ 1-5, 8-16: U = 0.048 CZ 6-7: U = 0.065	Same as ≤ 400 ft2	Same as ≤ 400 ft2
Extension of existing wood-framed wall Or Existing wood-framed wall with exterior siding (or cladding) to remain	R-15 in 2x4 wood framing R-21 in 2x6 wood framing	Same as ≤ 400 ft2	Same as ≤ 400 ft2
Raised floor¹ insulation	All CZs: R-19 or U = 0.037	Same as ≤ 400 ft2	Same as ≤ 400 ft2
Slab floor¹ perimeter insulation	CZ 1-15: No requirement CZ1: R-7 or U = 0.58	Same as ≤ 400 ft2	Same as ≤ 400 ft2

1. See Table 150.1-A and 150.1-B for requirements for non-framed walls including mass walls

Component	Additions ≤ 400 ft²	Additions > 400 and ≤700 ft²	Additions > 700 ft²
New structure	No requirement	Same as ≤ 400 ft²	All CZs: Required (Does not apply to any altered spaces)
Converting unconditioned to conditioned space	No requirement	Same as ≤ 400 ft²	Same as above except: Window and door header insulation Air sealing if the existing air barrier is not removed or replaced

Component	Additions ≤ 400 ft²	Additions > 400 and ≤700 ft	Additions > 700 ft²
Ventilation cooling¹(whole-house fan)	No Requirement	Same requirements as ≤400 ft²	Additions ≤ 1000 ft² – no requirement Additions > 1,000 ft2: CZ 8-14 - required
Adding new space conditioning system(s)	All prescriptive requirements	Same requirements as ≤400 ft²	All except requirement for ducts in conditioned space²
Replacing existing space conditioning system(s)	All prescriptive requirements	Same requirements as ≤400 ft²	All except requirement for ducts in conditioned space²
Adding all new complete duct system(s)	All prescriptive requirements	Same requirements as ≤400 ft²	All except requirement for ducts in conditioned space²
Extending existing duct system(s)	All duct insulation, duct system sealing, and HERS verification	Same requirements as ≤400 ft²	All duct insulation, duct system sealing, and HERS verification, Except requirements for ducts in conditioned space²

1. (Note: also, mandatory mechanical ventilation per ASHRAE 62.2 with HERS verification for additions > 1,000 ft2)

9.4.2 Water Heating System

If an addition increases the number of water heaters serving a dwelling unit, the addition can comply prescriptively if one of the conditions contained in §150.2(a)1Di-iv are met.

9.4.3 Alterations – Prescriptive/Mandatory Requirements

This section provides a road map and a few relevant summaries that identify the requirements unique to alterations. Envelope, mechanical, and water-heating system alterations must meet all applicable mandatory requirements and comply with either the prescriptive or performance approach. If a building does not meet all applicable prescriptive requirements, then the performance method using of approved compliance software is the alternative. This section describes the mandatory requirements for single-family residential buildings as they apply to additions and alterations. More information on the mandatory requirements can be found in Chapters 3, 4, 5, and 6.

Residential lighting alterations need to meet applicable mandatory requirements. There are no prescriptive lighting requirements in residential buildings.

Although alterations must meet many of the same prescriptive requirements for newly constructed buildings and additions, there are several exceptions or special allowances for certain types of alterations.

9.4.4 Envelope Alterations

This section summarizes requirements for many typical residential envelope alterations.

Table 9-8: Single-family Alterations Summary of Mandatory and Prescriptive Requirements

Envelope Alteration Type	Applicable Mandatory Requirements¹	Summary of Relevant Prescriptive Requirements²	Exception(s) to the Prescriptive Requirements
Altered Ceiling	Ceiling w/ attic and roof rafters: R-19, U=0.054 §150.0(a)	R-49 (U=0.20) attic insulation: CZ 1-4, 6, 8-16 Recessed can lights covered with insulation to the same depth as the rest of the ceiling: CZ 1-4, 8-16 Air sealing: CZ 2,4,8-16 Min. attic ventilation: all CZs §150.2(b)1J	1. R-38 existing attic insulation. 2. Asbestos or knob and tube wiring in the attic. 3. Attic space is shared with another dwelling unit which does not have an altered ceiling. The above conditions exempt a project from all the prescriptive requirements. Other exceptions apply to individual requirements, see Section 9.4.3.2 for further details.
Altered rafter roof	R-19, U=0.054 §150.0(a)	N/A	N/A
Adding exterior framed wall insulation	In 2x4 framing: R-13, U=0.102 In 2x6 framing: R-20, U=0.071 Exception: 2x4 framing already insulated to R-11 or greater per §150.0(c)1	N/A	N/A
Mass/concrete walls	See §150.1(c) for applicable climate zone	N/A	N/A
Replacing > 50% of existing steep-sloped (≥2:12) roof surface, including adding a new surface layer on top of existing exterior surface	§110.8(i)	Cool Roof Requirements CZ 4, 8 - 15: Reflect.≥0.20 and Emittance≥0.75; or SRI≥16 §150.2(b)1Ii	(a) Air space 1.0" between roof deck and bottom of roofing product (b) Profile ratio of rise to width of 1:5 for >50% width of roofing product. (c) Existing ducts in attic insulated and sealed per §150.1(c)9. (ad) Roof has ≥ R-38 ceiling insulation. (be) Roof has a radiant barrier per §150.1(c)2 (not over spaced sheathing). (c) In CZ 2, 4, 9, 10, 12, & 14 no ducts in attic. (d) >≥R-2.0 insulation above roof deck (e) Roof area covered by building integrated PV or solar thermal panels. (f) Roof constructions with a weight ≥25 lbs/ft².
Replacing > 50% of existing low-sloped (<2:12) roof surface, including adding a new surface layer on top of existing exterior surface	§110.8(i)	Cool Roof Requirements CZ 4,6 - 15: Reflectance ≥ 0.63; Emittance ≥ 0.75 §150.2(b)1Iiia	(a) There are no ducts in the attic. (b) Reflectance and Roof Deck Insulation R-value in Table 150.2-A are met (c) Roof area covered by building integrated PV or solar thermal panels. (d) Roof constructions with a weight ≥25 lbs/ft².
Adding or replacing skylight³	Weighted average U-factor ≤0.58 Exemption: Up to 20 ft² or 0.5% of conditioned floor area, whichever is greater, is exempt from the U-factor requirement of §150.0(q)	Must not exceed 20% total (all CZs) and 5% west fenestration area (CZ 2, 4, 6-15) with a U-factor ≤ 0.30 (all CZs); in CZ2, 4 & 6-15: SHGC ≤ 0.23 §150.2(b)1A	Up to 75 ft² need not meet total or west-facing fenestration area per §150.2(b)1A Exception 1 Replacement skylights up to 16 ft² with a U≤0.55 and SHGC ≤0.30 and not meet total fenestration and west-facing area requirements per §150.2(b)1A Exception 2
Adding raised floor insulation	R-19 or equivalent U-factor Exception: Floors over controlled ventilation or unvented crawlspaces per §150.0(d)	N/A	N/A
Replacing vertical fenestration³ (altered glazing)	Weighted average U-factor ≤0.58 Exemption: Up to 10 ft² or 0.5% of conditioned floor area, whichever is greater, is exempt from the U-factor requirement of §150.0(q)	Must not exceed 20% total (all CZs) and 5% west fenestration area (CZ 2, 4, 6-15) with a U-factor ≤ 0.30 (all CZs); in CZ2, 4 & 6-15: SHGC ≤ 0.23 §150.2(b)1A	Up to 75 ft² need not meet total or west-facing fenestration area per §150.2(b)1A Exception 1 Replacement skylights up to 16 ft² with a U≤0.55 and SHGC ≤0.30 and not meet total fenestration and west-facing area requirements per §150.2(b)1A Exception 2
Adding vertical fenestration³ (new glazing) and greenhouse	Weighted average U-factor ≤0.58 Exemption: Up to 10 ft² or 0.5% of conditioned floor area, whichever is greater, is exempt from the U-factor requirement of §150.0(q)	Must not exceed 20% total (all CZs) and 5% west fenestration area (CZ 2, 4, 6-15) with a U-factor ≤ 0.30 (all CZs); in CZ2, 4 & 6-15: SHGC =≤ 0.23 §150.2(b)1A	Up to 75 ft² need not meet total or west-facing fenestration area per §150.2(b)1A Exception 1 Added greenhouse must either meet the maximum or weighted average U-factor of 0.58 or up to 10ft² or 0.5% of CFA whichever is greater as per Exception 1 to §150.0(q)1

1. Alterations must comply with all applicable mandatory measures in §110.0 and §150.0 of the Energy Standards as explained in Chapters 3, 4, 5 and 6 of this manual, except as noted in §150.2(b).

3. Replacement fenestration may include fenestration that is located in the same existing wall or roof in which the same or larger area of existing fenestration is being removed. This is labeled as “altered.” Any new fenestration area that increases the total net area of fenestration in any existing wall or roof is labeled as “new.”

9.4.4.1 Replacing the Roof Surface or Roof Sheathing (Partial or Entire Replacement)

If 50 percent or more of the roof surface of an existing building is being altered, either by replacing the existing roof or adding a new surface lay on top of the existing surface, the following requirement must be met.

Steep-sloped roofs will need to meet a cool roof product requirement when 50 percent or more of the roof surface of an existing building is being replaced. In climate zones 4, and 8 through 15, the new roof products for the replaced steep-sloped roofing area shall have a minimum aged solar reflectance of 0.20 and minimum thermal emittance of 0.75, or a minimum SRI of 16. These requirements apply unless one of the following is present per Exception 1 to §150.2(b)1Ii:

1. Building has at least R-38 insulation or ceiling assemblies with maximum U-factor of 0.025.

3. There are no ducts in the attic space in climate zones 2, 4, 9, 10, 12 and 14.

4. Buildings with R-2.0 or greater continuous insulation above or below the roof deck.

Exception 2 to Section 150.2(b)1Ii exempts roof areas covered by building integrated photovoltaic panels or building integrated solar thermal panels from meeting the roofing product requirements.

Exception 3 to Section 150.2(b)1Ii exempts roof constructions with a weight of at least 25 pounds per square foot from meeting the roofing product requirements.

In climate zones 4, and 6 through 15, the new roof products for the replaced low-sloped roofing area shall have a minimum aged solar reflectance of 0.63 and minimum thermal emittance of 0.75, or a minimum SRI of 75 per §150.2(b)1Iiia.

Exception 1 to §150.2(b)1Iiia allows the aged solar reflectance to be traded off by adding insulation at the roof deck as specified in Table 150.2-B of the Energy Code.

Exception 2 to Section 150.2(b)1Iii exempts roof areas covered by building integrated photovoltaic panels or building integrated solar thermal panels from meeting the roofing product requirements

Exception 3 to Section 150.2(b)1Iii exempts roof constructions with a weight of at least 25 pounds per square foot from meeting the roofing product requirements.

In addition to the roofing product requirements, low-sloped roofs in climate zones 1, 2, 4, and 8 through 16, shall be insulated to meet either continuous insulation of R-14 or a roof assembly U-factor of 0.039 per §150.2(b)1Iiib. There are some exceptions to the insulation requirements.

Exception 1 to Section 150.2(b)1Iiib exempts existing roofs with R-10 or greater continuous insulation above or below the roof deck.

Exception 2 to Section 150.2(b)1Iiib exempts existing roofs in climate zones 1, 2, 4, and 8 through 10 with an assembly U-factor of 0.056 or less or that are insulated with at least R-19 insulation between the roof rafters and in contact with the roof deck.

Exception 3 to Section 150.2(b)1Iiib allows the continuous insulation requirements to be reduced to R-4 when meeting either of the following conditions:

1. Mechanical equipment located on the roof will not be temporarily disconnected and lifted as part of the roof replacement. And the addition of insulation required would reduce the height from the roof surface to the top of the base flashing to less than what is required by the manufacturer’s installation instructions as per the California Residential Code Section R900

2. Replaced roofing abuts sidewall or parapet walls and the addition of insulation required would reduce the height from the roof surface to the top of the base flashing to less than what is required by the manufacturer’s installation instructions as per California Residential Code Section R900, when all the following conditions apply:

a. The sidewall or parapet walls are finished with an exterior cladding material other than the roof covering membrane material.

b. The sidewall or parapet walls have exterior cladding material that must be removed to install the new roof covering membrane to maintain the minimum base flashing height.

c. The ratio of the replaced roof area to the linear dimension of affected sidewall or parapet walls is less than 25 square feet per linear foot.

Exception 4 to Section 150.2(b)1Iiib allows the continuous insulation requirements to be reduced where increasing the thickness of above deck insulation would reduce the flashing around an existing exterior wall opening below what is permitted by the fenestration or door manufacturer’s installation instructions, or registered design professionals approved flashing design, as per the California Residential Code Section R703.4, or by California Residential Code Section R905.2.8.3.

Exception 5 to Section 150.2(b)1Biib allows tapered insulation with lower thermal resistance at the drains and other low points to be used, provided that the thickness of insulation is increased at the high points of the roof so that the average thermal resistance equals or exceeds the required value.

Cool roofs are not just white roofs but are products (tile, asphalt shingles, etc.) designed to reflect much of the sun's radiant energy back into space instead of transferring it as heat into the building below. The two basic characteristics that determine the performance of a cool roof are solar reflectance and thermal emittance. These roofing products must be certified by the Cool Roof Rating Council (www.coolroofs.org) per §§10-113 and 110.8(i).

A cool roof requires the roofing product manufacturer to test for solar reflectance and thermal emittance and be listed in the Cool Roof Rating Councils (CRRC) Rated Product Directory. Figure 9-5 an example of an approved CRRC product label.

If the aged value for the reflectance is not available in the CRRC Rated Product Directory, the equation below is used.

Where:

l = Initial Reflectance listed in the CRRC Rated Product Directory
β = soiling resistance value listed in Table 9-10

Since this is not a mandatory requirement, prescriptive compliance for a given roof slope and climate zone require a minimum reflectance and emittance, can be met using one of the exceptions above or by using the performance compliance approach.

Example 9-12

Question:

There is a Victorian building that has been converted into an office building and needs to have a shake roof replacement. This building has a vented unconditioned attic with the insulation on the ceiling. Would I need to meet §150.2(b)Hi?

Answer:

No, this section does not apply. The occupancy type has been changed to nonresidential. Since the Victorian building has a shake roof and is considered a steep-sloped roof, §141.0(b)2Bib for nonresidential buildings would apply.

Example 9-13

Question:

On an existing building, 50 ft² of 85 ft² of vertical glazing is being removed from an existing south-facing wall and new glazing will be replaced as part of the alteration in the same opening. What requirements apply?

Answer:

Since 50 ft² is “replacement” fenestration and 35 ft² is existing, the replaced fenestration must comply with the §150.2(b)1B. For this example, Exception 1 to §150.2(b)1B can used. This allows vertical fenestration no greater than 75 ft²to meet have a U-factor no greater than 0.40 in Climate Zones 1-16 and an SHGC of 0.35 or less in Climate Zones 2, 4, and 6 through 15.

Example 9-14

Question:

Why is the low-sloped roofing products requirement listed for only Climate Zones 13 and 15?

Answer:

These two climate zones are the only climate zones that show energy cost-effectiveness for having a low-slope roofing product (cool roof) requirement.

Example 9-15

Question:

Why are there so many exceptions to the addition and alterations section that can be considered equivalents to roofing products?

Answer:

There are several energy features that are equivalent or having a greater impact on energy savings than the roofing products. For example, older homes often have ducts under the house, and newer homes may have materials slightly below current requirements or equal to one of the items considered to be equivalent. If the ducts are insulated and air leakage controlled to meet current requirements, energy savings are expected to be at least equal the benefit of reflective roof coverings.

Example 9-16

Question:

What happens if I have a low-slope roof on most of the house but a steep-sloped roof on another portion? Do I have to meet two criteria for the roofing products?

Answer:

Yes. If your house is in Climate Zone 13 or 15, you will need to meet the low-slope criteria for the areas with low slope. The areas with the steep-slope roof will need to meet the other cool roof criteria.

Example 9-17

Question:

I am replacing my existing wood shake roof with asphalt shingles. Would this be considered a repair?

Answer:

No. A repair is defined as a reconstruction or renewal for maintenance of any component, system, or equipment of an existing building. A replacement of any component (i.e., roof-top), system, or equipment for which there are requirements in the Energy Code is considered an alteration and not a repair.

Example 9-18

Question:

If a radiant barrier is required for my addition, where does it need to be installed?

Answer:

The radiant barrier needs to be installed only on the underside of an attic roof assembly and the gable wall ends associated with the addition.

Example 9-19

Question:

I am considering reroofing my house. Under what conditions will I be required to put on a cool roof?

Answer:

Cool roof requirements are triggered when 50 percent or more of the roof area is being replaced. Prescriptive requirements are waived if one of the exceptions to §150.2(b)1H below applies:

1. Air-space of 1.0 inch (25 mm) is provided between the top of the roof deck and the bottom of the roofing product.

2. The installed roofing product has a profile ratio of rise to width of 1 to 5 for 50 percent or greater of the width of the roofing product.

3. If existing ducts in the attic are insulated and sealed according to §150.1(c)9.

5. Buildings have an attic radiant barrier meeting the requirements of §150.1(c)2.

7. Buildings are in Climate Zones 10-15, R-2 or greater insulation above the roof deck.

2. Aged solar reflectance and roof deck insulation R-value in Table 150.2-A are met.

9.4.4.2 Insulating Existing Roof/Ceilings

When insulating a rafter roof, at least R-19 (maximum U-factor of 0.054) is required.

When a roof surface is altered, if the space between framing members becomes accessible, the ceiling/roof is considered altered, and insulation is required.

The prescriptive requirement for alterations to walls and floors is to add the equivalent of the specified level of insulation that fits within the cavity of wood-framed assemblies:

1. R-13 in 2x4 exterior walls, and R-20 in 2x6 or greater exterior walls (no exterior continuous insulation is required); or

2. Existing 2x4 exterior walls that already have R-11 insulation installed in framed walls are exempt from the mandatory minimum R-13 wall insulation required by §150.0(c); or

3. R-19 in raised floors over crawl spaces, over open outdoor areas, unheated basements, and garages.

Attic insulation and air sealing prescriptive requirements in vented attics apply when the ceiling above a conditioned space is altered or when an entirely new duct system is installed in the vented attic. A ceiling may be considered altered under various conditions including when the existing attic insulation is replaced, new attic insulation is added, or the ceiling plane is replaced.

Most single-family homes in California contain vented attics. On hot days, a typical vented attic is hotter than outside and if poorly ventilated the temperature difference between the attic and outdoors can be substantial. In homes with little or no attic insulation, this temperature difference can result in significant total heat gain or loss through the ceiling. High levels of attic insulation and an air barrier at the ceiling is an important approach to minimize those gains and losses and result in considerable energy savings.

A common circumstance that results in the disruption of existing attic insulation occurs when a new duct system is installed in a vented attic. At minimum, existing insulation is moved to access certain areas and then replaced. Sometimes, insulation is disturbed and left unfixed. In cases where penetrations are added to the ceiling layer for new registers, air sealing is critical to limit gains or losses to and from the home. By requiring insulation improvements and proper air sealing at duct replacement, vented attics are addressed as a system saving energy and improving comfort for the occupant.

When an attic is altered or a new duct system is installed, there are four primary sets of requirements that must be met as listed below.

3. Insulate over all recessed can lighting fixtures. Any recessed can lighting fixtures not rated for insulation contact (IC-rated) must be replaced with IC-rated fixtures or have a fire rated cover installed over the attic side of the fixture to allow for insulation to be installed over the fixtures.

A HERS Rater is not required to verify any of these prescriptive requirements. All requirements will be verified by an official from the building department.

These components combine to form a package that addresses many issues in existing attics. Combined they provide a much greater benefit than any of these measures do on their own. If an attic is insulated without first air sealing the ceiling assembly, the opportunity to seal any penetrations between the attic and conditioned space below is lost, and sealing can only be performed in the future if the insulation is removed. Once installed, R-49 insulation is 16-20” deep and it becomes a challenge to maneuver around the attic space. Air infiltration through the ceiling plane between the attic and conditioned space also reduces the effectiveness of attic insulation.

Items #1 through #3 above may or may not be required depending on climate zone and the existing attic insulation level. For projects that are subject to all or a portion of these requirements, the first step is to identify which requirements apply. Air sealing, recessed cans, and attic ventilation must be addressed prior to adding attic insulation. Table 9-11 below summarizes when these prescriptive requirements apply.

¹Mandatory minimum R-19 insulation requirements still apply if the ceiling is being altered.

If any of the following four conditions are met, the project is exempt from all of the four requirements:

(b) Alteration directly causes the disturbance of asbestos located in the ceiling, attic, or ductwork and remediation of asbestos is not being done as part of the scope of work.

(d) Altered attic space is shared with other dwelling units whose attic space is not considered altered.

If any of the exceptions are being claimed the existing conditions must be documented on the Certificate of Compliance which can be completed and signed by the homeowner, contractor, energy consultant, or any other party taking responsibility for the documentation. The existing conditions will be verified by the building official.

To qualify for the exceptions based on a minimum of R-19 or R-38 attic insulation, existing insulation must be documented to meet the minimum levels on the Certificate of Compliance. To verify the existing insulation R-value, the depth of insulation must be measured. To obtain an accurate measurement it’s recommended to measure in at least two places and take the average. If the depths across various sections of the attic differ by more than two of inches, measurements at the lower sections should be used. For example, if half of the attic has 6 inches of insulation and the other half has only 3-1/2” of insulation, a depth of 3-1/2” should be used for purposes of determining the existing insulation level. Next, multiply the depth of insulation by the R-value per inch based on the insulation product type. See Table 9-12 below for typical insulation densities for various product types. For the example above, if the insulation was high density cellulose at R-3.2 per inch, then the R-19 minimum condition is not met because half of the attic has insulation with an R-value of approximately R-13.

In Climate Zones 2, 4, and 8 through 16, where existing attic insulation is less than R-19, all accessible areas of the attic floor between the attic and the conditioned space must be air sealed (see Table 9-13). Homes with atmospherically vented space heating or water heating combustion appliances located inside the building pressure boundary are exempt from this requirement. This exception does not cover combustion appliances located in a vented attic, garage, or crawlspace.

Addressing air leakage requires removing or temporarily moving any existing insulation around the attic to access the attic floor. Most air sealing can be completed with caulking or foam. Areas where large holes might exist, such as at soffits and dropped ceilings, will require an air barrier to be installed if not already in place and the perimeter will need to be secured and fully sealed. Areas that present sources of air leakage that should be inspected when sealing the attic include:

In Climate Zones 1-4 and 8-16 any recessed can fixtures in the ceiling shall be covered with insulation to the same depth as the rest of the attic floor. Fixtures not rated for insulation contact must be replaced or retrofitted with a fire-proof cover that allows for insulation to be installed directly over the cover. Homes in Climate Zones 1-4 and 8-10 with existing attic insulation of R-19 or greater are exempt from this requirement. Table 9-14 summarizes the recessed can lighting requirements by climate zone and existing insulation value.

For recessed can fixtures to be directly covered with insulation the fixtures must be rated for Insulation Contact (IC). Fixtures that are IC rated usually have an Underwriters Laboratory (UL) sticker or stamp on the inside of the housing that says “IC” in some form. The lamp will likely need to be removed to properly view the housing. If the housing has slits or holes in it, it is not IC rated. If it cannot be determined whether a fixture is IC rated or not, it should be assumed that it is not. Recessed cans that are not IC rated present a serious fire hazard if they are surrounded by any flammable material because of the heat generated by the fixture. In these cases, the fixtures must be dammed to maintain separation between them and the attic insulation. This results in areas of the attic floor with minimal or no insulation where heat gains and losses are high, contributing to degraded insulation performance across the entire attic.

When present, older recessed can lighting can be a significant contributor to air leakage through a ceiling plane. Existing recessed cans typically are not airtight, and their perimeter can present a path for conditioned air to flow into the attic or unconditioned attic air to enter the conditioned space below. In addition to an IC rating, recessed can fixtures can also be rated to be “Airtight”. This prescriptive standard does not require that existing fixtures be airtight. However, if existing recessed fixtures are being entirely replaced with new luminaires, the requirements of Section 150.0(k)1C must be met which requires the fixtures be certified as airtight with air leakage tested in accordance with ASTM E283 to be less than 2 cfm at 75 Pascals. Existing fixtures that are IC rated but not airtight can be retrofit with a retrofit trim kit which provides an airtight enclosure. Recessed cans that are not IC or AT rated may be replaced with IC rated housing units designed for retrofit applications.

In some cases, a fire-rated attic recessed light cover, shaped as domes or boxes, can be installed over the fixture allowing for insulation to be installed directly up to and over the cover. The recessed can fixture must have a thermal switch, which disconnect the electricity to the light if the temperature exceeds unsafe levels. The covers are to be installed over existing fixtures and sealed around the perimeter to the ceiling floor. Example covers include the TENMAT and Insullite covers (see Figure 9-6). Products that act as dams for the can lighting but do not allow insulation to cover the area over the fixture are not acceptable for meet these prescriptive requirements. If it cannot be determined whether the fixture has a thermal switch, assume that it is does not, and a fire-rated recessed light cover cannot be used.

Figure 9-6: Example fire rated cover products. Left is Tenmat, and right is Insullite.

In all climate zones, except 5 and 7, attic insulation shall be installed at the attic floor to a level of R-49 or to achieve a weighted U-factor of 0.020. Table 9-15 summarizes the insulation requirements by climate zone, based on whether the existing attic insulation meets a minimum R-19 or not.

In cases where there is limited vertical height in an attic (preventing the installation of the required insulation R-value), an exception allows for the installation of a lower R-value. Insulation must still be installed to maximize the depth of insulation while still meeting code requirements for roof ventilation as specified in Section 806.3 of the California Residential Code (Title 24, Part 2.5). A minimum of 1 inch air gap must be provided between the insulation and roof deck as well as at all vent locations. The use of blocking, bridging and insulation must not block the free flow of air.

Attic insulation is either batt, loose fill (blown-in), rigid, or spray foam and can be made of various materials. Most new and retrofit attics use blown-in fiberglass or cellulose insulation. Blown-in insulation is a loose fill product installed using a blowing machine with a large, attached hose. While both blown-in and batt insulation have similar properties, it is much easier to achieve a consistent installation with loose fill since the particles more easily fill in small gaps and hard to reach areas. R-value ratings per inch vary somewhat by product type and across manufacturers. Manufacturers provide coverage charts which specify how many bags of insulation are needed to cover a certain square footage based on the ceiling framing spacing and depth. The charts account for settling of the insulation due to compression under its own weight.

Insulation must be installed evenly throughout the attic space and insulation levels must be documented on the certificate of installation (CF2R). The insulation level can be verified by checking that the depth of insulation conforms to the manufacturer’s coverage chart for achieving the required R-value. The insulation also must meet the manufacturer’s specified minimum weight per ft² for the corresponding R-value. When using loose fill insulation at the ceiling, baffles should be installed at eaves or soffit vents to keep the insulation from blocking ventilation and prevent air movement under the insulation. Attic access doors shall have permanently attached insulation using adhesive or mechanical fasteners.

When any work is conducted in an existing attic, ventilation is required to be reviewed and altered as necessary to ensure compliance with current code requirements per the California Building Code. Ventilation allows the natural flow of air that removes accumulated warm air and moisture from the attic. The relevant requirements that usually need to be addressed from Title 24, Part 2.5 Section R806 are listed below.

• A minimum net free ventilating area of 1/150 of the area of the attic space.

• Ventilation openings shall be no smaller than 1/16” and no greater than 1/4".

Ridge baffles should be installed when ceiling insulation is next to eave or soffit vents. The baffles should be placed at the top plate to direct ventilation air up and over the ceiling insulation. It is important to ensure the baffle extends sufficiently beyond the height of the ceiling insulation so as not to disturb the insulation.

Example 9-22

Question:

I want to improve the performance of my existing vented attic and add attic insulation. The existing insulation is only about 3 inches deep. Is there a minimum insulation level that I must meet? Are there other requirements that apply to my project?

Answer:

In Climate Zones 1 through 4, 6, and 8 through 16, a minimum of R-49 insulation shall be installed at the ceiling level or a weighted U-factor of 0.020 shall be achieved. In Climate Zones 5 and 7 only the mandatory minimum R-19 ceiling insulation must be met. Additionally, air sealing of all accessible areas between the attic and conditioned space is required in Climate Zones 2, 4, and 8 through 16. The air sealing should be performed in accordance with Section 110.7. In Climate Zones 1 through 4 and 8 through 16 any existing recessed can lights must be rated for insulation contact or retrofitted with a fire-proof cover that allows for insulation to be installed directly over the cover. In all climate zones, if attic ventilation does not meet California Building Code requirements it must be increased to meet current code. There are exceptions for various existing conditions, see Section 9.4.4.2 for further detail.

Question:

What if I have an atmospherically vented water heater inside a closet in my house?

Answer:

If space heating or water heating combustion appliances that are atmospherically vented are located inside the pressure boundary of the home, the project is exempt from the air sealing requirement. The other requirements still apply based on climate zone.

Question:

What if my existing ceiling insulation is R-19?

Answer:

With an existing minimum insulation level of R-19, in Climate Zones 1, 3, and 5-7 none of the attic insulation, air sealing, or insulation covering recessed can requirements apply. In Climate Zones 2, 4, and 8-16 projects are only required to meet the insulation and attic ventilation requirements and are exempt from the air sealing and insulation covering recessed can requirements.

Question:

What if my existing ceiling insulation is R-38?

Answer:

The project is exempt from all the prescriptive requirements.

Example 9-23

Question:

I am installing two new recessed can fixtures in my kitchen, do I have to meet the prescriptive attic insulation and air sealing requirements for an altered ceiling?

Answer:

No, this is a lighting alteration and does not constitute a ceiling alteration. The new recessed can fixtures must meet the requirements of Section 150.0(k).

Example 9-24

Question:

I am installing a new duct system in my vented attic, but I have asbestos insulation and knob and tube wiring, am I required to insulate and air seal my attic?

Answer:

No, the project is exempt from all the prescriptive requirements if either asbestos or knob and tube wiring is in the vented attic where work is being conducted. If asbestos abatement is occurring to remove asbestos on existing ductwork, and no other exceptions exist, then the prescriptive requirements still apply.

9.4.4.3 Fenestration and Doors

Any fenestration (i.e., windows, skylights, clerestories, and glazed doors) that is being removed and replaced in an exterior wall or roof is considered “replacement fenestration.”

Replacement fenestration is an area of new fenestration that replaces an equal or lesser area of glazing removed in the same existing wall or roof area. It is labeled as “altered” fenestration, and it need not occur in the same openings as the glazing being removed as long as it is being installed in the same existing wall or roof surface that remains a part of the existing building. Any added fenestration area that is larger than the total altered glazing area is labeled as “new.”

The Energy Code has relaxed some of the prescriptive restrictions on new vertical fenestration for alterations in existing homes. When new vertical fenestration is added in existing dwellings, up to 75 ft² are not required to meet the overall total fenestrations limit (20 percent of the CFA) and the west facing area limit (5 percent of the CFA). This provides for additional flexibility to meet the Energy Code requirements using the prescriptive approach, without having to comply using the performance approach. However, this additional fenestration must meet the prescriptive U-factor and SHGC requirements or meet the U-factor and SHGC requirements of Exceptions 1 and 2 to §150.2(b)1B.

Greenhouse or garden windows are special windows that project from the façade of the building and are typically five-sided structures. An NFRC-rated U-factor for greenhouse windows is typically high and may not meet the mandatory requirements for the fenestration U-factor of 0.58.

2. Must use the area-weighted average for all new and replacement fenestration with a combined mandatory maximum of 0.58 U-factor as per §150.0(q)2; or

3. Must meet the Exception 1 to §150.0(q)1 for up to 10 ft² or 0.5 percent of CFA, whichever is greater.

Alterations that add exterior door area must meet the same requirements as newly constructed buildings (Section 150.1(c)5) which requires a maximum U-factor of 0.20 for swinging doors. Swinging doors between the garage and conditioned space that are required to have fire protection are exempt from the U-factor requirement.

See Chapter 3 for a full list of mandatory requirements for certification and labeling for fenestration products and exterior doors (§110.6), and air leakage requirements (§110.7).

Example 9-25

Question:

An alteration in Climate Zone 12 is to move an existing 25 ft² window to another location within the same existing wall. What prescriptive requirements does the relocated window need to meet?

Answer:

Removing glazing from an existing wall and reinserting up to the same area of glazing in a different opening is an alteration, covered by §150.2(b)1B. Exception 1 to §150.2(b)1B states that up to 75 ft² of vertical replacement fenestration is allowed to meet a prescriptive requirement of 0.40 U-factor and 0.35 SHGC.

Example 9-26

Question:

For additions and alterations that include a greenhouse window (also known as garden window), how do I measure the fenestration area? What U-factor and SHGC requirements apply to a greenhouse window?

Answer:

The area of a greenhouse windows is the rough opening in the wall.

The default U-factor for greenhouse windows does not meet the mandatory maximum fenestration U-factor of 0.58 (there is no mandatory SHGC requirement). A metal-framed greenhouse window from Table 110.6-A has a 1.40 U-factor and the default SHGC from Table 110.6-B is 0.73 (for fixed, clear glass). By comparison, fenestration in prescriptive additions has to meet the prescriptive U-factor of 0.30 for all climate zones and an SHGC of 0.23 in all climate zones except 1, 3, 5, and 16, which have no SHGC requirement. There are two options to meet the mandatory U-factor requirement: (1) up to 30 ft² is exempt (§150.0[q], Exception 2), and (2) a weighted-average U-factor with other fenestration products is allowed.

For additions and alterations, Exception 1 to §150.2(b) allows any dual-pane greenhouse window to meet the prescriptive U-factor requirement (separate from the mandatory requirement). This makes it possible for greenhouse windows to comply as part of a prescriptive alteration if there is no SHGC requirement (Climate Zones 1, 3, 5, and 16). For climate zones with an SHGC requirement, if other windows are being altered, a weight-average SHGC may be calculated, or performance compliance is an option for achieving compliance. Compliance will likely depend on higher-than-average energy efficiency for some other components of the project to offset the poor performance of the greenhouse windows.

For other alternatives, see Chapter 3.

Example 9-27

Question:

An existing house in Climate Zone 12 has all single-pane windows. Most of the windows (300 ft² total) will be replaced within existing openings. One existing 30 ft² window is being replaced with a pair of 40 ft²French doors. What requirements apply to this project?

Answer:

For prescriptive compliance, replacement fenestration (equal to or less than the area of existing windows in each wall being altered) and added fenestration area must meet the U-factor (0.30) and SHGC (0.23) in Table 150.1-A or B. There are only 10 ft² of added fenestration, so the project meets Exception 1 to §150.2(b)1A and is not required to meet the prescriptive total glazing area requirement. All installed fenestration also must meet applicable mandatory requirements.

For performance compliance:

(a) Using the Existing + Alterations approach without third-party verification, replacement fenestration that achieves the fenestration values in Table 150.2-D of the Energy Code is compared to those same values in the standard design. Replacement fenestration that does not reach these values is penalized.

(b) Using the Existing + Alterations approach with third-party verification, replacement fenestration that achieves the fenestration values in Table 150.2-D of the Energy Code is compared to §Tables 110.6-A and 110.6-B default values for the existing fenestration condition. Replacement fenestration that does not reach these values is penalized.

Example 9-28

Question:

An existing building has all single-pane, metal-frame windows. A proposed remodel will replace all the windows; no other work is being done as part of the remodel. What applies?

Answer:

All replacement windows must meet the prescriptive requirements (§150.2[b]1B), and new fenestration must meet applicable mandatory requirements of C1V10.6, 110.7, and 150.0.

If the prescriptive requirements cannot be met, the Existing + Alteration performance method can be used.

Example 9-29

Question:

An existing building has all single-pane, wood-framed windows. In addition to replacing more than 75 ft² of window area, two double-pane, metal-frame greenhouse windows will be added. How should the greenhouse windows be shown to comply using the prescriptive standards?

Answer:

Greenhouse windows add conditioned volume but do not add conditioned floor area. There are three unique requirements (1) prescriptive SHGC, (2) prescriptive U-factor, and (3) mandatory U-factor. Any dual-glazed greenhouse windows installed as part of an alteration must meet any SHGC requirements (0.23 or lower in Climate Zones 2, 4, 6-15, no requirement in other climate zones). While the prescriptive U-factor requirements do not apply (§150.2[b] Exception 1), all applicable mandatory requirements must be met. This includes §150.0(q), which requires a maximum weighted average U-factor of 0.58 or less. Exception 2 exempts up to 30 ft² from this requirement.

9.4.5 Water Heating Alterations

For a replacement water heater, there are separate requirements for the distribution system and the water heater. The requirements for pipe insulation are mandatory and cannot be traded off. For the distribution system and the water heater, if the prescriptive requirements cannot be met, then the performance compliance method can be used to comply.

1. Any newly installed and existing accessible piping must meet mandatory insulation requirements in §150.0(j)1.

To meet the prescriptive requirements, the replacement water heater must be one of the following:

2. A single heat pump water heater meeting NEEA Tier 3 or higher specifications.

3. A single heat pump water heater, (1) located in an unconditioned space like the garage or in conditioned space, (2) placed on an incompressible (rigid) surface that is insulated to a minimum R-10, and (3) installed with a communication interface (demand control device) meeting §110.12(a), or has an ANSI/CTA-20450B communication port.

4. If the existing water heater is an electric resistance water heater, a replacement electric resistance water heater may be installed.

5. A water-heating system determined by the California Energy Commission’s Executive Director to use no more energy than those specified above.

If a recirculation system is installed, then it must be a demand recirculation system with a manual on/off control to meet the prescriptive requirements.

9.4.5.1 Trouble-shooting Water Heater Problems

If installing a recirculation system to reduce the long wait time for hot water, the only system type allowed in an alteration is a demand recirculation system with manual on/off controls. Any other alteration to the hot water distribution system, such as timer or temperature control recirculation systems, must be analyzed using the performance compliance approach to show that the energy use of the building has not been increased.

Another alternative is to install a natural gas or propane instantaneous (tankless) water heater closer to the fixtures having problems. Any other type of water heater may be installed as long as compliance is demonstrated using the performance compliance approach. (See Section 9.5.)

Example 9-26

Question:

I want to install a second water heater for an addition to a single-family home with an existing natural gas water heater. Does this comply?

Answer:

It depends on the type of water heater. A heat pump water heater or instantaneous gas or propane water heater meeting certain conditions of 200,000 Btu/h or less complies with §150.2(a)1D. For small additions 500 square feet or less an instantaneous electric water heater meeting certain conditions is also allowed. Otherwise, performance compliance may be used to demonstrate compliance.

Example 9-27

Question:

An existing 1,500 ft² single-family home is getting a 500 ft² addition. A new 50-gallon gas water heater will replace the existing water heating system. How do the water heating requirements apply?

Answer:

Because this is an alteration or replacement (§150.2[b]1H) of an existing water heating system, this proposed replacement meets the requirement of §150.2(b)1Hiiia.

Any applicable mandatory requirements must also be met. For newly installed piping and existing accessible piping, all the applicable insulation requirements of §150.0(j)1 shall be met. If building energy compliance is achieved with the existing + addition + alterations calculation, the UEF or EF and other energy features of the altered water heating system are modeled in the performance method.

Example 9-28

Question:

An existing 2,000 ft² single-family house has one 50-gallon gas water heater, and a 600 ft² addition with a new instantaneous gas water heater is proposed. How does this comply?

Answer:

When there is an increase in the number of water heaters with an addition, the Energy Code allows addition-alone compliance in certain circumstances. An instantaneous gas water heater of 200,000 Btu/h or less is one of those circumstances. Compliance with applicable mandatory requirements is also needed.

The alternative to show compliance is by using the existing-plus-addition or whole-building compliance.

Example 9-29

Question:

An existing single-family home with one electric water heater has a 500 ft² addition with a 30-gallon electric water heater proposed. Does this comply with prescriptive addition requirements?

Answer:

No. When there is an increase in the number of water heaters with an addition, . Per §150.2(a)1Div, the only prescriptive electric resistance option for additions up to 500 ft2 is an instantaneous water heater.

Performance compliance may be possible. There is a significant penalty for this type of electric resistance water heating.

Example 9-30 − Alterations

Question:

If my house has an electric-resistance water heater and I plan to upgrade my water heater, do I need to install a gas instantaneous, gas storage water heater, or HPWH?

Answer

No, if natural gas is not already connected to the existing water heater location, then a consumer electric water heater that meets the requirements of California’s Appliance Efficiency Regulations can replace the existing water heater. If installing new piping to the water heater, then you will need to comply with the mandatory pipe insulation requirements. See Section 5.3.5.1 for more information on pipe insulation requirement.

9.4.6 HVAC System Alterations

If the heating and cooling system is unchanged as part of an addition or alteration, compliance for the HVAC system is not necessary. However, altering or replacing any component of a system typically triggers requirements for that component, as well as a requirement for duct sealing and leakage testing. Residential Appendices RA3 contains the applicable field verification and diagnostic test protocols that must be followed.

Energy Code requirements are determined by the type of the work performed on the existing space conditioning system. In practice, this work is commonly referred to as an “HVAC changeout”. The two types of HVAC changeouts are:

9.4.6.1 Entirely New or Complete Replacement Space Conditioning Systems

A system installed in an existing dwelling as part of an alteration shall be considered entirely new when:

1. The air handler and all the system heating/cooling equipment (e.g., outdoor condensing unit and indoor cooling or heating coil for split systems; or complete replacement of a package unit), are new.

2. The duct system is entirely new (including systems with less than 40 feet in length).

An entirely new or complete replacement must meet all applicable mandatory requirements and prescriptive requirements as described below (See Chapter 4 for details).

8. §150.0(m)13: Static pressure probe, airflow, and fan efficacy requirements (or alternative return duct sizing as per Table 160.3-A and 160.3-B).

9.4.6.2

9.4.6.2.1 Altered Duct Systems

New ducts that are installed to replace or extend existing ducts must comply with the mandatory duct insulation, labeling and damper requirements of §150.0(m)1-10 (see Chapter 4 for details). When more than 25 feet of new ducts are installed, additional duct insulation and duct sealing and leakage testing requirements must be met, as described below.

New ducts installed in an unconditioned space must be insulated to a minimum R-value as described in Table 9-16.

The duct system must also be sealed by the installer and verified by a HERS Rater as specified in RA3.1 (duct leakage test), regardless of whether the ducts are located in unconditioned space. The only exception is if the existing duct system contains asbestos.

• If the new ducts form an entirely new duct system, the measured duct leakage must be equal or less than 5 percent of the system airflow. The duct system must also meet the air filtration requirements, and the static pressure probe, airflow, and fan efficacy requirements (§150.0[m]12 and §150.0[m]13). If the air handler and ducts are located in a vented attic, then attic and air sealing requirements (§150.2[b]1J) apply, as described in Section 9.4.4.2. An entirely new duct system is having at least 75 percent of new duct material, and up to 25 percent of reused parts that must be accessible.

• If the new ducts (more than 25 feet installed) do not form an entirely new duct system, the measured duct leakage must be equal to or less than 10 percent of the system airflow, or the measured duct leakage to outside must be equal to or less than 7 percent of the system airflow. If it is not possible to meet either of these duct leakage targets (which must be performed first), then all accessible leaks must be sealed and verified through a visual inspection and a smoke test by a HERS rater.

When performing a visual inspection and smoke test, sampling is not allowed. The HERS rater must perform the inspection and test on every house. Some judgement is required in determining if ducts are accessible, where the local enforcement agency will have the final say when it is not immediately obvious.

9.4.6.2.2 Altered Space Conditioning Equipment

New space conditioning equipment that is installed, typically as equipment replacements, must comply with the applicable mandatory requirements for the new equipment (See Chapter 4 for details). In addition, this altering of space conditioning equipment triggers duct sealing and leakage testing, and other requirements as described below.

The duct system connected to the altered equipment must be sealed by the installer and verified by a HERS Rater as specified in RA3.1 under any of the following conditions:

2. An outdoor condensing unit of a split system air conditioner or heat pump is installed or replaced.

The measured duct leakage must be equal to or less than 10 percent of the system airflow, or the measured duct leakage to outside must be equal to or less than 7 percent of the system airflow. If it is not possible to meet either of these duct leakage targets (which must be performed first), then all accessible leaks must be sealed and verified through a visual inspection and a smoke test by a HERS rater.

There are a few cases where duct sealing and duct leakage verification are not required. These exceptions include:

3. Duct systems that contain asbestos. See Blueprint Issue 130, Q&A: Residential Duct Testing.

Additionally, when altered ducts, air-handling units, cooling or heating coils, or plenums are located in a garage, the ducts must be the sealed by a HERS rater to a measured duct leakage of 6 percent or less of the system airflow. The alternative to this is having all accessible leaks located in the garage space sealed and verified through a visual inspection and a smoke test by a HERS rater. This requirement applies when any length of new ducts is installed (not limited 25 feet of ducts).

In Climate Zones 2 and 8 through 15, when a refrigerant-containing component of an air conditioner or heat pump is replaced or installed in an existing house, §150.2(b)1F requires a system that does not have a fault indicator display (FID) installed to have refrigerant charge field verified (RCV) in accordance with all applicable procedures specified in RA3.2.2, or RA1. When RCV is required for compliance, the system must also comply with the minimum airflow of 250 cfm/ton for small duct high velocity systems and 300 cfm/ton for all other systems, according to the procedures specified in RA3.3.

For all climate zones, when an existing system has a refrigerant containing component added or replaced the thermostat must be upgraded to a digital setback type that meets §110.2(c)

If the space heating system is being replaced, the replacement system must not use electric resistance as the primary heat source unless one of the following exceptions is met:

1. The existing system is electric resistance, and the replacement system is nonducted.

2. The existing system is electric resistance, and a ducted space cooling system is not being replaced or installed.

3. The existing system is electric resistance and located in Climate Zone 7 or 15.

Example 9-31

Question:

Do I have to seal the ducts if I replace the outdoor units in my house without changing the indoor unit?

Answer:

Yes. Replacing the outdoor unit (or indoor unit) by itself will trigger the duct sealing and verification requirement. The alteration requirements differ from newly constructed building requirements. (See §150.2[b]1Ei through iii for the requirements and exceptions.)

Example 9-32

Question:

I have an existing electric furnace and I’m adding a new bedroom. Can I extend the existing ducts to the new room and use the existing furnace?

Answer:

Yes. If ducts are extended (of any length) from an existing space-conditioning system, compliance requires meeting the mandatory duct requirements, and the additional prescriptive duct insulation and duct sealing and leakage testing requirements. The existing furnace must also have adequate heating capacity to meet California Building Code requirements for the additional space.

Example 9-33

Question:

I am adding a bedroom to a house that has a central forced-air natural gas furnace. I would like to heat the room with an electric resistance baseboard heater rather than extend the existing ductwork to reach the new space. Is this allowed?

Answer:

Not using prescriptive compliance. This is only possible if using performance compliance and the relatively high energy consumption of the electric resistance heater is made up by reductions from other energy efficiency features in the addition or in an accompanying alteration.

Example 9-34

Question:

My central gas furnace stopped working. If I get a new efficient unit rather than repair the existing one, what are the requirements?

Answer:

Mandatory requirements apply to the components being replaced. The furnace must meet minimum efficiency requirements, but all systems sold in California should already meet the minimum efficiency requirements. If the new system includes mechanical cooling, and the existing thermostat is not a setback thermostat, it must be replaced with a setback thermostat (§150.2[b]1Fi).

All new ducts must meet insulation and construction requirements. All existing and new ducts must be sealed and HERS-verified, as specified §150.2(b)1E.

Prescriptively, the new heating unit must be natural gas fueled or a heat pump. A CF1R-ALT-02 can be completed by you or your mechanical contractor and registered on a HERS Provider’s website.

Example 9-35

Question:

As part of an upgrade in an existing house, one of the ducts is being replaced because of deterioration of the insulation. What requirements apply to the replacement duct?

Answer:

This is an alteration to the space-conditioning system; therefore, the mandatory requirements for ducts apply. If more than 25 feet of the duct is altered, the requirements of §150.2(b)1D trigger diagnostic testing and HERS verification of the duct system, as well as the prescriptive duct insulation requirements.

Example 9-36

Question:

An upflow air-handling unit with a furnace and air conditioning coil is located on a platform in the garage of an existing house. The platform is used as a return air plenum. The air-handling unit is being replaced, and the platform is being repositioned to the corner of the garage (three feet away from the current location). What requirements apply to this alteration?

Answer:

The mandatory requirements apply to this alteration. In particular, §150.0(m) prohibits raised platforms or building cavities from being used to convey conditioned air (including return air and supply air). When the platform is relocated, it is being altered, and the mandatory requirement applies. Ducts made from sheet metal, duct board, or flexible ducts must be installed to carry the return air to the replaced air handler.

Since the air handler is being replaced the prescriptive duct sealing requirements of §150.2(b)1D and E, which apply to ducts in garage spaces, would require either 6 percent duct leakage or a visual inspection and smoke test. (See Section Error: Reference source not found.)

Example 9-37

Question:

What is meant by the term "air handler"?

Answer:

The term "air handler" is used to identify the system component that provides the central system forced-air movement for the ducted heating or cooling space-conditioning system. The term "air handler" may be properly used to identify various types of central system forced-air-moving components that must meet the functional requirements for different types of space-conditioning systems. For instance, a "gas furnace" air handler includes a gas combustion heat exchanger and the central system fan, but does not include a direct expansion (DX) cooling coil; an "electric furnace" air handler has electric heating coils and the central system fan, but does not include a DX cooling coil; a "fan-coil unit" air handler for a split system heat pump has a DX cooling/heating coil and a central system fan; a “hydronic heat pump” air handler includes the air-side DX coil, compressor, water-cooled condenser, and the central system fan. There are other air handler configuration variations as well.

Example 9-38

Question:

I have a residential building that was constructed in the 1920s. It has a freestanding gas furnace, and I want to change it to an electric wall heater. Is this permitted?

Answer:

No. Section 150.2(b)1Ciiii states that the new space-conditioning system be limited to natural gas, liquefied petroleum gas, or the existing fuel type. The only electric option is a heat pump.

Example 9-39

Question:

I am replacing only my heat pump equipment. What requirements apply for my duct system?

Answer:

When a space conditioning system is altered duct sealing requirements are triggered. If the ducts are not being replaced, the existing duct system needs to be tested by the installer and a HERS Rater to have no greater than 10% total leakage or 7% leakage to outside. If this leakage criteria cannot be met, a smoke test and visual verification may be conducted by a HERS Rater to verify that all accessible ducts have bene sealed.

Example 9-40

Question:

What are the duct sealing requirements if am I replacing or adding 20 feet or more of ducts located in my garage?

Answer:

When replacing or adding any length of ducts in garage spaces or altering any space conditioning equipment in a garage (including air-handling units, cooling or heating coils, or plenums) duct sealing requirements apply. Ducts must be tested by the installer and a HERS Rater to have leakage less than or equal to 6% of air handler airflow. If this leakage criteria cannot be met, a smoke test and visual verification may be conducted by a HERS Rater to verify that all accessible ducts have bene sealed.

Example 9-41

Question:

I am replacing an existing ducted electric resistance furnace and am installing central A/C, can I install another electric resistance furnace?

Answer:

In climate zones 1-6, 8-14, and 16 no. When replacing an existing ducted electric resistance furnace in these climate zones, the only time another ducted electric resistance furnace can be installed is when ducted air conditioning is not being replaced or installed new. Otherwise, a heat pump or gas or propane heating system is required. In Climate Zones 7 and 15 an electric resistance furnace may be installed in this case.

Question:

What if I am replacing baseboard electric heating in addition to adding a central A/C system?

Answer:

When the replacement heating system is ductless, such as with baseboard heating, this is allowed whenever the existing system is electric resistance.

9.4.7 Mechanical Ventilation for Additions and Alterations

The whole-dwelling unit ventilation and local mechanical exhaust requirements apply to additions and alterations based on specific conditions as described in this section. See Chapter 4 for details on mechanical ventilation requirements.

9.4.7.1 Additions

• An addition to an existing dwelling unit that increase the conditioned floor area by more than 1,000 square feet must have the required whole-dwelling unit ventilation airflow calculated by using the entire dwelling unit conditioned floor area. This is the existing conditioned floor area plus the added conditioned floor area.

• An addition that adds a new dwelling unit to an existing building must have the required whole-dwelling unit ventilation airflow calculated by using the conditioned floor area of the new dwelling unit.

Additions less than 1,000 square feet of conditioned floor area and additions that add a junior accessory dwelling unit (JADUs) do not need to meet the whole-dwelling unit ventilation requirements.

The local mechanical exhaust requirements of §150.0(o)1G and §150.0(o)2 must also be met, as applicable, when a kitchen or bathroom is added as part of an addition.

9.4.7.2 Alterations

Alterations that install a new or completely replaces an existing ventilation system must comply with all the applicable requirements in §150.0(o). An entirely new or complete replacement ventilation systems is a new ventilation fan component and an entirely new duct system. An entirely new duct system is constructed of at least 75 percent new duct material, and up to 25 percent may consist of reused parts from the dwelling unit's existing duct system if the reused parts are accessible and can be sealed to prevent leakage.

• Dwellings that were previously required by a building permit to comply with whole-dwelling ventilation requirements, are required to comply with the current whole-dwelling ventilation airflow specified in §150.0(o)1C. Field verification and diagnostic testing of airflow performance are required in accordance with the procedures in Residential Appendix RA3.7. In that case, a Certificate of Compliance CF1R form must be registered online with a HERS Provider. (See Section 2.5 and Appendix A.)

• All replacement whole-dwelling unit ventilation fans must be rated for airflow and sound in accordance with ASHRAE 62.2 Section 7.1. When meeting whole-dwelling unit ventilation airflow is required (as described above), the replacement ventilation fan must be rated to deliver an airflow rate that is equal to or greater than the required airflow.

• If the air filtration device is altered or replaced it must comply with the ventilation system air filtration requirements in §150.0(m)12 for dwellings that were previously required by a building permit to comply with the air filtration requirements.

• All altered bathroom local exhaust systems must comply with the applicable requirements of §150.0(o)1G.

• Altered kitchen exhaust systems for dwellings that were previously required by a building permit to comply with the kitchen local exhaust requirements in §150.0(o)1G are required to meet or exceed the applicable airflow or capture efficiency requirements specified in §150.0(o)1G.

• Altered kitchen exhaust systems for dwellings that were previously required by a building permit to install a vented kitchen range hood or other kitchen exhaust fan are required to install a replacement fan that meets or exceeds the airflow required by the previous building permit, or 100 cfm, whichever is greater.

• All replacement local mechanical exhaust fans must be rated for airflow and sound in accordance with ASHRAE 62.2 Section 7.1 and Title 24, Part 6 Section 150.0(o)1Gvi. When meeting an exhaust airflow is required (as described above), the replacement exhaust fan must be rated to deliver an airflow rate that is equal to or greater than the required airflow.

9.4.8 Lighting for Additions and Alterations

Highlights of the residential lighting requirements are listed below. All residential indoor and outdoor lighting requirements are mandatory. Details of the 2022 Energy Code residential lighting requirements can be found in Chapter 6.

2. Screw based luminaire requirements, see §150.0(k)1B and Residential Compliance Manual Section 6.2.5

3. Recessed downlight luminaires in ceilings, see §150.0(k)1C and Residential Compliance Manual Section 6.2.3

4. Indoor lighting control requirements, see §150.0(k)2 and Residential Compliance Manual Section 6.3

5. Outdoor luminaires and lighting controls requirements, see §150.0(k)3 and Residential Compliance Manual Section 6.4.1 and 6.4.2

6. Internally illuminated address sign requirements, see §150.0(k)4 and Residential Compliance Manual Section 6.4.3

Altered lighting and any newly installed lighting equipment are required to comply with the residential lighting standards, which apply to permanently installed lighting and associated lighting controls.

Only the lighting equipment that is altered needs to comply with the Energy Code. Existing lighting equipment is not required to be replaced to comply.

Example 9-42

Question:

I am remodeling and renovating my whole home and putting in an entirely new indoor lighting system. How does the Energy Code apply to the new lighting system?

Answer:

When an entirely new lighting system is installed, it is treated like required for a newly constructed building. The new indoor lighting system must meet the lighting requirements in §150.0(k)1, Table 150.0-A and 150.0(k)2.

If the remodeling includes any lighting in garages with eight or more vehicles, there are also applicable requirements in §150.0(k)5.

Example 9-43

Question:

I am doing minor renovations to my kitchen that has six recessed incandescent cans and I am adding a new luminaire over the sink. How does the Energy Code apply to the new luminaire and the altered luminaires in this case?

Answer:

The new luminaire and the altered luminaires must meet the luminaire efficacy requirements of Section 150.0(k)1 and Table 150.0-A. Where existing screw base sockets are present in ceiling-recessed luminaires, removal of these sockets is not required provided that new JA8 compliant trim kits or lamps designed for use with recessed downlights or luminaires are installed.

Example 9-44

Question:

In the kitchen above, I am replacing one of the recessed downlight luminaires. Must the new downlight luminaire be high luminous-efficacy?

Answer:

Yes, newly installed luminaires must be high luminous-efficacy and meet the requirements in §150.0(k)1 and Table 150.0-A. Screw-based sockets are not permitted for newly installed recessed downlight luminaires in ceilings.

Example 9-45

Question:

I am replacing my incandescent bath bar in the bathroom. Must the new luminaire meet the Energy Code requirements?

Answer:

The new luminaire is the altered component and must meet requirements in §150.0(k)1 and Table 150.0-A, including the high luminous-efficacy luminaires and the lighting controls requirements. The 2022 Energy Code now allows the installation of Joint Appendix JA8-compliant lamps in screw-based fixtures as a way to comply with the high luminous-efficacy lighting requirements as long as the luminaire is not a recessed downlight in ceiling. See Sections 6.2 and 6.3 of this manual for details.

Component	Option B	Option C (CZ 4, 8-16)
Roof Deck Insulation	Below-deck insulation CZ 4, 8-16: R-19	No roof deck insulation required
Radiant Barrier	CZ 2-3, 5-7	CZ 2-15
Roofing	Tile roof or other product with an air space	Tile roof or other product with an air space
Ceiling Insulation	CZ 1, 2, 4, 8-16: R-38 CZ 3, 5-7: R-30	CZ 2-10: R-30 CZ 1, 11-16: R-38
Duct and Air Handler Location	Attic	Conditioned space

Component	Additions ≤ 400 ft²	Additions > 400 and ≤700 ft²	Additions > 700 ft²
Allowable total glazing area	Up to 75 ft² or 30% of conditioned floor area, whichever is greater	Up to 120 ft² or 25% of conditioned floor area, whichever is greater	Up to 175 ft² or 20% of conditioned floor area, whichever is greater
Allowable west-facing glazing area: CZ 2, 4, 6-15	Up to 60 ft²	Up to 60 ft2	The greater of 70 ft² or 5% of conditioned floor area in CZ 2, 4, 6-15
Glazing U-factor & SHGC¹	All CZs: U = 0.30 CZ 2, 4 & 6-15: SHGC = 0.23	All CZs: U = 0.30 CZ 2, 4 & 6-15: SHGC = 0.23	All CZs: U = 0.30 CZ 2, 4 & 6-15: SHGC = 0.23
Opaque door U-factor	U = 0.20	U = 0.20	U = 0.20

Minimum Aged Solar Reflectance	Roof Deck Continuous Insulation R-value Climate Zones 6-7	Roof Deck Continuous Insulation R-value Climate Zones 2, 4, 8-15
0.60	R-2	R-16
0.55	R-4	R-18
0.50	R-6	R-20
0.45	R-8	R-22
No requirement	R-10	R-24

PRODUCT TYPE	β
Field-applied coating	0.65
Other	0.70

Climate Zones	Building with < R-19 existing attic insulation	Building with ≥ R-19 existing attic insulation
5, 7	Attic ventilation only1	Attic ventilation only
6	R-49, attic ventilation	Attic ventilation only
1, 3	R-49, recessed cans, attic ventilation	Attic ventilation only
2, 4, 8-10	R-49, recessed cans & air sealing, attic ventilation	R-49, attic ventilation
11-16	R-49, recessed cans & air sealing, attic ventilation	R-49 & recessed cans, attic ventilation

Climate Zones	< R-19 existing attic insulation	≥ R-19 existing attic insulation
1, 3, 5-7	No requirement	No requirement
2, 4, 8-10	Yes	No requirement
11-16	Yes	No requirement

Climate Zone	3, 5 through 7	1, 2, 4, 8 through 16
Duct R-value	R-6	R-8