9.4       Mandatory Requirements

The mandatory measures apply to all newly added or altered envelope components regardless of whether the prescriptive or performance compliance method is used. 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.

9.4.1          Envelope Measures

Envelope mandatory measures are listed below, including the relevant reference in the Energy Standards and the section number in this manual. The following measures include fenestration products, exterior doors, insulation, roofing products, and radiant barriers. See Sections 3.23.8 and the Energy Standards for more information.

A.   Manufactured fenestration products and exterior doors air leakage infiltration rates, see §110.6(a)1, Section

B.   Fenestration U-factor, SHGC, VT ratings, see §10-111, §110.6(a)2, 3 & 4,

C.   Fenestration temporary and permanent labels, see §110.6(a)5, Section

D.   Fenestration maximum weighted average U-factor = 0.58, see §150.0(q),

E.   Installation of field-fabricated fenestration and exterior doors, see §110.6(b), Section 3.5.3

F.   Sealing joints and other openings, see §110.7, Section

G.   Certification of insulating materials, see §110.8(a), Section

H.   Restrictions on use of urea formaldehyde foam insulation, see §110.8(b),

I.     Flame spread insulation ratings, see §110.8(c), Section

J.    Insulation placement on roof/ceilings, see §150.0(a), Section;

K.   Minimum roof/ceiling insulation, see §150.0(a), Section

L.    Minimum roof/ceiling insulation in an existing attic, see §110.8(d)1 and §150.0(a), Section

M.   Roofing products (cool roofs) solar reflectance and thermal emittance rating and labeling, see §10-113 and §110.8(i), Section

N.   Radiant barrier, see §110.8(j), Section

O.   Loose-fill insulation, see §150.0(b), see Section

P.   Minimum wall insulation, see §150.0(c), see Section

Q.   Minimum floor insulation, see §150.0(d), see Section

R.   Slab edge insulation moisture resistance and physical protection, see §150.0(f), Section

S.   Insulation requirement for heated slab floors, see §110.8(g), Section

T.   Vapor retarder §150.0(g), see Section      Ceiling/Roof and Wall Insulation

When insulation is installed in the attics of existing buildings, at least R-22 shall be installed in all climate zones. When ceilings without attics are altered, at least R-19 shall be installed between wood-framing members, or enough insulation shall be installed to achieve the equivalent of R-19 insulation between wood-framing members. When the space between framing members becomes accessible as a part of a ceiling/roof modification, the ceiling/roof is considered altered, and the insulation measure applies. However, if the roofing surface material is replaced but the roof sheathing is not being removed, there is no insulation requirement.

Existing buildings that already have R-11 insulation installed in framed walls are exempt from the mandatory minimum R-13 or R-19 wall insulation required by §150.0(c) if the building can demonstrate performance method compliance with the walls modeled as R-11.      Roofing Products: Cool Roof

Roofing products installed to meet prescriptive requirements or to take performance compliance credit for reflectance and emittance are referred to as “cool roofs” Cool roofs are specially 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).

To be considered a cool roof, the roofing products manufacturer must have its roofing product tested for solar reflectance and thermal emittance, and be listed in the Cool Roof Rating Councils (CRRC) Rated Product Directory. Figure 9-1 provides an example of an approved CRRC product label.

Figure 9-1: CRRC Product Label and Information

If the aged value for the reflectance is not available in the CRRC’s Rated Product Directory, then the equation below can be used until the aged rated value for the reflectance is posted in the directory.


Equation 9-1: Aged Reflectance

Aged Reflectancecalculated = (0.2+β[ρinitial – 0.2])

ρinitial = Initial Reflectance listed in the CRRC Rated Product Directory
β = soiling resistance value listed in Table 9-2


Table 9-2: Soiling Resistance Value β, by Product Type



Field-applied coating



0.70      Fenestration

New or replacement (altered) glazing, including skylights, must meet the maximum U-factor requirement in one of three ways:

1.    All fenestration products (glazed opening) must meet the mandatory maximum U-factor of 0.58; or

2.    All new or replacement fenestration combined must meet the mandatory maximum of 0.58 U-factor using an area weighted average calculation; or

3.    The area of new and replacement fenestration up to 10 ft2 or 0.5 percent of the conditioned floor area (CFA), whichever is greater, is exempt from the maximum U-factor requirement per Exception to §150.0(q).

Example: An existing 2,500 ft2 house undergoes an alteration with all the existing windows being replaced. The owner may install up to 12.5 ft2 of new glazing (that is, up to 0.5 percent of 2,500 ft2) without meeting the maximum U-factor of 0.58, if the overall alterations meet the Energy Standards with the prescriptive or performance approach.

Consistent with Exception 1 to §150.1(c)3A: For each dwelling unit, up to 3 ft2 of new glazing area installed in doors and up to 3 ft2 of new tubular skylight area with dual-pane diffusers shall not be required to meet or be included in the area-weighted average fenestration calculation to meet the mandatory requirement of §150.0(q).      Greenhouse Windows

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

For new buildings and additions, §150.0(q) includes an exception from the U-factor requirement for dual-glazed greenhouse or garden windows that total up to 30 ft² of fenestration area. However, the exempted area shall be included in the area-weighted average calculation.

For additions with more than 30ft2 of greenhouse and garden windows, the area-weighted average for all new and replacement fenestration must be used to show that the combined average U-factor complies with the U-factor requirement.

For alterations, dual-glazed greenhouse or garden windows are deemed to comply with U-factor requirements.

9.4.2          Mechanical (HVAC) and Water Heating Measures

Mechanical (HVAC) system and water-heating mandatory measures are listed below for additions and alterations. They include measures applicable to space-conditioning equipment, controls, and systems; water heaters, controls, and systems, pool and spa equipment, controls, and systems; outdoor air ventilation; pipe insulation; air ducts and plenums; and fireplaces. See Energy Standards and manual section references below:

1.    Appliance efficiencies and verification, see §110.1, Section 4.1.4

2.    Space conditioning equipment efficiencies, see §110.2(a), Sections 4.2.1 & 4.3.1

3.    Heat pump controls, see §110.2(b), Sections

4.    Setback thermostats (in most cases), see §110.2(c), Section 4.5.1

5.    No continuously burning gas pilot lights, see §110.5, Sections

6.    Heating and cooling load calculations, see §150.0(h), Sections &

7.    Pipe insulation and refrigerant line insulation, see §150.0(j), Section &

8.    Duct insulation and protection of insulation, see §150.0(m), Section 4.4.1

9.    Dampers to prevent air leakage, see §150.0(m), Section

10.  Flexible duct labeling, see §150.0(m), Section

11.  Duct connections and closures, see §150.0(m), Section

12.  Duct system sealing and leakage testing, see §150.0(m)11, Section

13.  Zonally controlled central forced-air systems, see §150.0(m)13, Section

14.  Mechanical ventilation for indoor air quality, see §150.0(o), Section 4.6

15.  Fireplaces, decorative gas appliances, and gas logs, see §150.0(e), Section

16.  Water-heating systems, see §150.0(n), Chapter 5

17.  Solar water heating, see §150.0(n)3, Section 5.5

18.  Pool systems and equipment installation, see §150.0(p), Section 5.6.

9.4.3          Mechanical Ventilation

The whole building ventilation airflow requirement in ASHRAE 62.2 is required only in new buildings and in buildings with additions greater than 1,000 ft2.  However, all other mechanical ventilation requirements in §150(o), including local exhaust, must be met, as applicable, in all additions and alterations.

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).

9.4.4          Lighting Measures

Highlights of the residential lighting measures are listed below. All residential indoor and outdoor lighting measures are mandatory. Details of the 2016 Energy Standards residential lighting requirements can be found in Chapter 6.

1.    Luminaire (light fixture) requirements, see §150.0(k)1, Section 6.2

2.    Indoor lighting controls, see §150.0(k)2, Section 6.3

3.    Lighting in bathrooms, garages, laundry rooms, and utility rooms, see §150.0(k)2J, Section 6.3.3

4.    Recessed downlight fixtures, see §150.0(k)1C, Section 6.2.3

5.    Outdoor lighting, see §150.0(k)3, Section 6.5

6.    Internally illuminated address signs, see §150.0(k)4, Section 6.5.4

7.    Residential garages for eight (8) or more vehicles, see §150.0(k)5, Section 6.6

8.    Interior common areas of low-rise multifamily buildings, see §150.0(k)6, Section 6.4

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 9-4


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?


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


Example 9-5


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


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


Example 9-6


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


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

See Section 6.2 and 6.3 of this manual for additional information.


Example 9-7


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


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 2016 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.