9.4 Prescriptive and Mandatory Measures

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 measures require HERS verification and/or testing, 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.

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 summarizes the key features of the prescriptive envelope requirements for the three prescriptive addition options in §150.2(a)1. Envelope requirements unique to that type of prescriptive addition are shown in bold.

The prescriptive requirements for additions are listed in §150.2(a)1. Unless otherwise noted, the prescriptive requirements contained in §150.1(c)7A also apply.

A. Additions ≤ 400 ft²: All prescriptive requirements must be met except:

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

5. Ceiling insulation of R-38 in Climate Zones 1 and 11-16, or R-30 in Climate Zones 2-10.

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:

B. Additions > 400 ft²and ≤ 700 ft²: All prescriptive requirements must be met except:

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 and 11-16 or R-30 in Climate Zones 2-10.

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:

9.4.1 Prescriptive Additions

To provide consistency with existing wall alignment, extensions of the existing wall into the addition shall have R-15 for 2x4 walls

Insulation requirements from Prescriptive table; unless addition is 700 ft²or less, then meet mandatory minimum roof/ceiling insulation

• For additions < 400 ft²: 75 ft²or 30% of CFA – whichever is greater -- for total glazing area; and 60 ft²for west-facing glazing.

• For additions > 400 ft²and < 700 ft²: 120 ft²or 25% of CFA – whichever is greater -- for total glazing area; and 60 ft²for west-facing glazing.

• For additions > 700 ft²: 175 ft²or 20% of CFA – whichever is greater -- for total glazing area; and 70 ft²or 5% of CFA – whichever is greater - for west-facing glazing.

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 40 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, 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, 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. Mandatory duct insulation requirements of §150.0(m) apply to any new ducts, including R-6.0 minimum in unconditioned space. All other mandatory requirements in §150.0 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.

For a summary and discussion of prescriptive mechanical requirements when installing new or replacement space-conditioning equipment and/or ducts, see Section 9.6.2.

Table 9-2: Envelope Roof/Ceiling Requirements for Prescriptive Additions

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

Table 9-3: Roof and Ceiling Requirements for Prescriptive Additions

Table 9-4: Envelope Door and Glazing Requirements for Prescriptive Additions

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

Table 9-6: QII Requirements for Prescriptive Additions

Table 9-7: HVAC and Water Heating Requirements for Prescriptive Additions

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)1D i or ii are met. The most common option is a natural gas or propane tankless water heater.

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 measures, then the performance method using of approved compliance software is the alternative. This section describes the mandatory requirements for low-rise residential buildings as they apply to additions and alterations. More information on the mandatory measures can be found in Chapters 3, 4, 5, and 6.

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

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

9.4.4 Envelope Alterations

Table 9-8: For Residential Alterations, Summary of Mandatory and Prescriptive Measures

Envelope Alteration Type	Applicable Mandatory Measures¹	Summary of Relevant Prescriptive Measure(s)²	Exception(s) to the Prescriptive Measures
Adding ceiling insulation to an existing roof; or a new roof on an existing building	Ceiling w/ attic and roof rafters: 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: Walls already insulated to R-11 §150.1(c)	Same as mandatory	N.A
Mass/concrete walls	See §150.1(c) for applicable climate zone	Same as mandatory	N/A
Replacing > 50% of existing roof surface, including adding a new surface layer on top of existing exterior surface	§110.8(i)	Steep-Sloped (≥ 2:12): CZ 10 - 15: Reflect.≥0.20 and Emittance≥0.75; or SRI≥16	(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. (d) Roof has ≥ R-38 ceiling insulation. (e) Roof has a radiant barrier per §150.1(c)2. (f) No ducts in attic. (g) In CZ10-15, >R-2.0 insulation above roof deck
	§110.8(i)	Low-Sloped (< 2:12): CZ13 & 15: Reflectance ≥ 0.63; Emittance ≥ 0.75	(a) There are no ducts in the attic. (b) Reflectance and Roof Deck Insulation R-value in Table 150.2-A are met
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)1H	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)	Same as mandatory	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)(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).
2. Several prescriptive measures are climate zone (CZ) specific.
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)

In Climate Zones 10 through 15, if 50 percent or more of the roof surface of an existing building is being replaced, the minimum cool roof requirement for the replaced steep-sloped roofing area shall have an aged solar reflectance of 0.20, thermal emittance equal to 0.75, or a minimum SRI of 16. The requirements above apply unless one of the following is present (considered equivalent to the cool roof requirements in §150.2(b)1Hi):

1. Air space of 1.0" (25mm) between the roof deck and the bottom of the roofing product.

2. Roofing product profile ratio of rise to width is at least 1:5 for >50 percent width of roofing product.

7. In Climate Zones 10 through 15, there is greater than R-2.0 insulation above the roof deck.

In Climate Zones 13 and 15, if 50 percent or more of the roof surface of an existing building is being replaced, the minimum cool roof requirements for low-sloped roofs shall have an aged solar reflectance of 0.63, thermal emittance of 0.75, or a minimum SRI of 75 per §150.2(b)1Hii. These apply unless one of the following is present, which is considered equivalent to the cool roof requirements in §150.2(b)1Hii:

2. The aged solar reflectance can be traded off with additional insulation added at the roof deck as specified in Table 150.2-B of the Energy Standards.

Table 9-9: Aged Solar Reflectance Insulation Trade Off

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

Table 9-10: Soiling Resistance Value β, by Product Type

Since this is not a mandatory requirement, if prescriptive compliance for a given roof slope and climate zone require a minimum reflectance and emittance, you can either meet one of the exceptions above or use the performance compliance approach to use some other building feature to trade off the requirement.

When insulation is added to an existing ceiling of an existing conditioned space, at least R-19 (or a maximum U-factor of 0.054) is required in all climate zones. 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-15 in 2x4 exterior walls, and R-21 in 2x6 or greater exterior walls (no exterior continuous insulation is required); or

2. Existing buildings that already have R-11 insulation installed in framed walls are exempt from the mandatory minimum R-13 or R-20 wall insulation required by §150.0(c) if the building can demonstrate performance compliance with the walls modeled as R-11; or

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

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 Standards have 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 Standards 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.

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 9-14

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 9-15

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 9-16

Question:

An existing house in Climate Zone 12 has all single-pane windows. Most of the windows (300 ft²total) 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 150.1-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 measures.

For performance compliance:

(a) Using the Existing + Alterations approach without third-party verification, replacement fenestration that achieves the fenestration values in Table 150.2-C of the Energy Standards 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-C of the Energy Standards is compared to Tables 110.6-A for U-factors and Table 110.6-B default values for the existing fenestration condition. Replacement fenestration that does not reach these values is penalized.

Example 9-17

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 measures of §110.6, §110.7, and §150.0.

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

Example 9-18

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 measures 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.

Example 9-19

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 9-20

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 9-21

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 9-22

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 Standards is considered an alteration and not a repair.

Example 9-23

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 9-24

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:

Prescriptive Exceptions for Steep-Sloped Roofs

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.

4. Buildings have at least R-38 ceiling insulation.

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

6. Buildings have no ducts in the attic.

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

Prescriptive Exceptions for Low-Sloped Roofs

1. Buildings have no ducts in the attic.

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

Alternatively, the building may show compliance using the performance approach.

Example 9-25

Question:

I am building a 450 ft² addition on my house. Do I have to meet cool roof requirements in the prescriptive package?

Answer:

Yes. Once the addition exceeds 300 ft², if using prescriptive compliance is in a climate zone with a cool roof requirement, the roof must meet the requirements for the type of roof slope. To avoid the cool roof requirements for this addition, you may use the performance approach and trade-off against other energy efficiency features of the addition alone or the existing building by using the Existing + Addition + Alterations approach.

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 piping must meet mandatory insulation requirements in §150.0(j)2.

2. Any accessible existing piping must be insulated on (1) the first 5 feet of cold water pipes from the storage tank, and (2) all hot water piping less than ¾-inch that is:

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

2. If there is no natural gas connected to the existing water heater location, a consumer electric water heater

4. In Climate Zones 1-15, 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).

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.

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 an additional water heater to a single-family home with an existing natural gas water heater. Does this comply?

Answer:

It depends on the type of water heater. An instantaneous gas or propane water heater complies with §150.2(a)1D. For prescriptive compliance, the same options allowed for new construction are allowed for an addition. (See Chapter 5.).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 measures must also be met. For newly installed piping, all the applicable insulation requirements of §150.0(j)2 shall be met. For existing piping that is accessible, the insulation requirements §150.0(j)2 shall be met, which includes the first five feet of cold water lines from the storage tank and all hot water piping. 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 Standards allow addition-alone compliance in certain circumstances. An instantaneous gas water heater 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, the prescriptive compliance option is to meet the same requirements as for new construction. The only electric option is a heat pump water heater. (See §150.1(c)8iv or v for a full list of requirements, or Chapter 5 of this manual.)

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

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. Changing, altering, or replacing any component of a system often triggers a requirement to seal the ducts. A HERS Rater verifies the duct leakage is less than 15 percent. However, since the ducts are existing, if 15 percent leakage is not feasible, there are alternatives, including all accessible leaks being sealed and confirmed by a visual inspection (Section 150.2(b)1E).

Extending ducts to condition an addition is not an alteration, however if more than 40 feet of new ductwork is installed in unconditioned space, Section 150.2(b)1D contains duct leakage requirements.

When the duct system is entirely new or a complete replacement, then mandatory and prescriptive requirements apply. (See below.)

The Energy Standards make a distinction between two HVAC "changeout" situations:

An entirely new or complete replacement must meet all applicable mandatory measures. (See Chapter 4.)

Completely new or replacement duct systems in multifamily dwelling units must meet the 12 percent (total leakage protocol) or 6 percent (leakage to outside protocol) criteria used for newly constructed systems (may also use the smoke test protocol if the system does not meet these criteria) (§150.2(b)1DiiallB). Otherwise, altered duct systems in multifamily dwelling units shall meet the 15 percent (total leakage protocol), 10 percent (leakage to outside protocol), or smoke test criteria given in §150.2(b)1DiiallB.

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).

Whether a duct system is altered or new affects which mandatory requirements apply and duct leakage requirements. An altered duct system installed in an existing home is entirely new when:

2. All remaining components from the previous system are accessible and can be sealed.

Entirely new or complete replacement systems must meet mandatory requirements including:

2. Section 150.0(m)13 – HSPP/PSPP, airflow and fan efficacy requirements (or alternative return duct sizing as per Table 150.0-B and C).

Altered duct systems that are not entirely new or complete replacements are treated as an extension of an existing system.

When any new ducts are installed in an unconditioned space, the duct must be insulated to a minimum R-value as described in Table 9-11.

Table 9-11: Duct Minimum R-Value

When more than 40 linear feet of ducts are installed in conditioned space, the ducts must be insulated to the minimum mandatory insulation level of R-4.2 and be verified to be in conditioned space by both visual verification and diagnostic testing in accordance to RA3.1.4.3.8.

A new duct system may include an existing air handler, which leaks substantially more than new equipment. If the 5 percent leakage rate criteria cannot be met, a smoke test should be performed to verify that the excess leakage is non-accessible and not from other accessible portions of the duct system. The protocol for the smoke test for accessible-duct sealing is given in RA3.1.4.3.7.

If 40 feet of duct are being added or replaced, this work alone can trigger the requirement for duct sealing and field verification. The system would have to meet one of the leakage criteria for “altered existing systems” cases in Table RA3.1-2.

All climate zones require that existing duct systems must be sealed by the installer and verified by a HERS Rater when portions of the heating and cooling system are altered.

When an air handler is installed or replaced, ducts must be sealed (as described below) under any of the following conditions:

If a residence has more than one duct system, only the ducts connected to the altered equipment need to be sealed and verified.

There are three options for showing compliance for existing duct systems listed below. The HERS Rater or installing contractor must at least attempt compliance with the first option (15 percent leakage); then any of the other options can be used:

1. Total leakage is less than 15 percent of nominal system fan airflow (RA3.1.4.3.1).

2. Leakage to the outside is less than 10 percent of system fan airflow (RA3.1.4.3.4).

• HERS field verification is required for all options listed above. For Options 1, and 2, verification can be accomplished through sampling as described in Sampling for Additions or Alterations below. For Option 3, sampling is not allowed; a certified HERS Rater must do the visual inspection and the smoke test on every house.

• Since test equipment must be set up for Option 1, it may be most efficient to test and record the results and then attempt to meet each option sequentially until compliance is achieved.

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

If altered ducts, heating or cooling equipment, or plenums are in a garage, the duct sealing requirements (not limited to 40 feet of new duct) are one of the following:

1. Leakage is less than or equal to 6 percent or air handler airflow (RA3.1.4.3.1).

2. All accessible leaks in the garage space are sealed, and both a visual verification and smoke test are performed by a HERS Rater using methods from RA3.1.4.3.5..

Some judgment is required in determining if ducts are accessible. The local code enforcement agency will have the final say when it is not immediately obvious.

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 building, §150.2(b)1F requires a system that does not have a fault indicator display (FID) installed to have refrigerant charge field verified in accordance with all applicable procedures specified in RA3.2.2, or Reference Appendix RA1.

1. Minimum Airflow. When RCV is required for compliance, the system must also comply with the minimum airflow of 300 cfm/ton according to the procedures specified in RA3.3.

Entirely new or complete replacement space-conditioning systems, as specified in §150.2(b)1C, must meet the minimum 350 cfm/ton airflow rate compliance criterion or the duct design alternative specified in §150.0(m)13.

2. Thermostats. 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)

See Chapter 4 for HVAC system replacement details for entirely new or complete replacements.

Prescriptive compliance requires new heating systems be limited to gas, propane, or the existing fuel type. The exception to this is a heat pump (§150.2(b)1G).

Example 9-30

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 new construction requirements. (See §150.2(b)1Ei through iii for the requirements and exceptions.)

Example 9-31

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 from an existing space-conditioning system, §150.2(b)1Dii includes three options for showing prescriptive compliance when more than 40 feet of new duct work is installed. The existing furnace must have adequate heating capacity to meet California Building Code requirements for the additional space.

Example 9-32

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 measures in the addition or in an accompanying alteration.

Note: If there are more than 40 linear feet of added ducts, the ducts must be sealed, tested, and verified as sealed by a HERS Rater.

Example 9-33

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)1Fii).

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 or a heat pump. A CF1R-ALT-02 or 03 form can be completed by you or your mechanical contractor. If HERS requirements apply this is done at the HERS Provider’s web-site.

Example 9-34

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 measures for ducts apply. If more than 40 feet of the duct is altered, the requirements of §150.2(b)1D trigger diagnostic testing and HERS verification of the duct system.

Example 9-35

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 9.4.6.1.)

Example 9-36

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 9-37

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)1Cii 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.

9.4.7 Mechanical Ventilation

The whole-building ventilation airflow requirement in ASHRAE 62.2 is required only in new buildings, new dwelling units, and buildings with additions greater than 1,000 ft². However, all other mechanical ventilation requirements in §150.0(o), including local exhaust, must be met, as applicable, in all additions and alterations.

When an addition is greater than 1,000 ft², the mechanical ventilation airflow rate is based on the conditioned floor area of the entire existing and new floor area of the dwelling unit (§150.2(a)1Ci).

When whole-building ventilation airflow is required for compliance, 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.)

9.4.8 Lighting Measures

Highlights of the residential lighting measures are listed below. All residential indoor and outdoor lighting measures are mandatory. Details of the 2019 Energy Standards residential lighting requirements can be found in Chapter 6.

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 Standards. Existing lighting equipment is not required to be replaced to comply with the Energy Standards.

Example 9-38

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. Does this luminaire have to be a high-efficacy luminaire?

Answer:

Yes, in kitchens, all new luminaires must be high-efficacy.

Example 9-39

Question:

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

Answer:

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

Example 9-40

Question:

I am completely remodeling my kitchen and putting in an entirely new lighting system. How do the Energy Standards apply to this case?

Answer:

When an entirely new lighting system is installed, it is treated like new construction. The new lighting system must comply with all the mandatory lighting requirements in §150.0(k)1 and (k)2.

Example 9-41

Question:

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

Answer:

The new luminaire is the altered component and must meet requirements in §150.0(k), including the high-efficacy luminaire and lighting control requirements. The 2019 Energy Standards now allow the installation of Joint Appendix JA8-compliant lamps in screw-based fixtures as a way to comply with the high-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	Additions ≤ 400 ft²	Additions > 400 and ≤700 ft²	Additions > 700 ft₂
Roof/Ceiling Insulation	CZ 1, 11-16: R-38 CZ 2-10: 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		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		CZ 2-15: Radiant barrier above attic spaces except when complying with Option B (see §150.1(c)2)

Component	Option B – Single Family	Option B - Multifamily	Option C (CZ 4, 8-16)
Roof Deck Insulation	Below-deck insulation CZ 4, 8-16: R-19	Below-deck insulation CZ 4, 8, 9, 11-15: R-19 CZ 10, 16: R-13	No roof deck insulation required
Radiant Barrier	CZ 2-3, 5-7	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	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 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	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
1. See §150.0(q) and §150.1(c)3 for new and replaced window and skylight exceptions.

Component	Additions ≤ 400 ft²	Additions > 400 and ≤700 ft²	Additions > 700 ft²
Exterior framed wall¹ insulation – single-family	CZ 1-5, 8-16: U = 0.048 CZ 6-7: U = 0.065	Same as ≤ 400 ft²	Same as ≤ 400 ft²
Exterior framed wall^1,2 insulation - multifamily	CZ 1-5, 8-16: U = 0.051 CZ 6-7: U = 0.065
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
Raised floor¹ insulation	All CZs: R-19 or U = 0.037
Slab floor¹ perimeter insulation	CZ 1-15: No requirement CZ1: R-7 or U = 0.58
1. See Table 150.1-A and 150.1-B for requirements for non-framed walls including mass walls 2. R-values refer to wood framing, and U-factors refer to metal framing.

Component	Additions ≤ 400 ft²	Additions > 400 and ≤700 ft²	Additions > 700 ft²
Single-family additions – new structure	No requirement	No requirement	All CZs: Required (Does not apply to any altered spaces)
Multifamily additions – new structure	No requirement	No requirement	CZ 1-6, 8-16: Required CZ 7: No requirement (Does not apply to any altered spaces)
Converting unconditioned to conditioned space	No requirement	No requirement	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 ft²	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		All except requirement for ducts in conditioned space²
Replacing existing space conditioning system(s)	All prescriptive requirements		All except requirement for ducts in conditioned space²
Adding all new complete duct system(s)	All prescriptive requirements		All except requirement for ducts in conditioned space²
Extending existing duct system(s) by > 40 feet	All duct insulation, duct system sealing, and HERS verification		All duct insulation, duct system sealing, and HERS verification, Except requirements for ducts in conditioned space²
1. 1. (Note: also mandatory mechanical ventilation per ASHRAE 62.2 with HERS verification for additions > 1,000 ft²) 2. 2. For more information about ducts in conditioned space, see Section 3.5.3.5.

Aged Solar Reflectance	Roof Deck Insulation R-value	Aged Solar Reflectance	Roof Deck Insulation R-value
0.62 – 0.60	2	0.44 – 0.40	12
0.59 -0.55	4	0.39 – 0.35	16
0.54 - 0.50	6	0.34 – 0.30	20
0.49 – 0.45	8	0.29 – 0.25	24

PRODUCT TYPE	β
Field-applied coating	0.65
Other	0.70

Climate Zone	1 -10, 12 & 13	11, 14 -16
Duct R-value	R-6	R-8