The most significant change in the 2022 Building Energy Efficiency Standards affecting single-family residential buildings is the change to a single fuel baseline with heat pump being prescriptively required for either water heating or space heating, depending on the climate zone. A new Energy Design Rating (EDR) metric, EDR1, was added that is based on hourly source energy. There are numerous new requirements for additions and alterations. There are also significant changes in requirements related to indoor air quality.
A. Mandatory Requirements:
1. Mandatory roof deck insulation in newly constructed attic systems in Climate Zones 4 and 8–16 to meet an area-weighted average U-factor no greater than 0.184 (§150.0[a]1).
2. Ducts in conditioned space can be uninsulated if specific conditions are met as explained in Section 140.6(a)3 (§150.0[m]1B).
3. Electric readiness is now required for space heating, cooking, and clothes dryers when gas equipment is installed. Electrical infrastructure must be provided to the equipment location for the future installation of electrical appliances. (§150.0[t]-[v]).
4. The electric-ready requirements for gas water heaters have been revised (§150.0[n]).
5. Updated mechanical ventilation requirements based on the 2019 version of ASHRAE 62.2 (§150.0[o]).
6. New requirements for central fan integrated ventilation systems requiring a motorized controlled damper (§150.0[o]1B).
7. Updated local exhaust requirements for kitchen range hoods. Gas ranges require higher ventilation rates or capture efficiencies than electric ranges. (§150.0[o]1G).
8. Simplify the hot water piping language and align with the Plumbing Code (§150.0[j]).
9. Updated HPWH-ready requirements for gas water heater installations that include providing a designated space for a future HPWH installation. (See Electric Readiness — Chapter 10.)
10. New battery storage-ready infrastructure requirements. (§150.0[s]).
B. Prescriptive Compliance:
1. Under the prescriptive compliance approach, the heating equipment is required to be a heat pump in Climate Zones 3, 4, 13, and 14. In other climate zones, it can be either a heat pump or a gas heating system (§150.1[c]6).
2. Under the prescriptive compliance approach, water heating equipment is required to be a heat pump water heater or a solar water heating system with electric backup and minimum 70 percent solar fraction. In Climate Zones 3, 4, 13, and 14 a gas instantaneous water heater is allowed (§150.1[c]8).
C. Performance Compliance:
1. All compliance software programs approved by the CEC use the same compliance engine as the public domain software. The technical details and information about how the energy budget is determined are included in the 2022 Single-Family Residential Buildings Alternative Compliance Manual (ACM) Reference Manual.
2. A new Energy Design Rating (EDR) metric, EDR1, was added that is based on hourly source energy. What was referred to as just “Efficiency EDR” in the 2019 code is now efficiency EDR2.
D. Compliance requires meeting three components of an Energy Design Rating…
(EDR): (1) EDR (source), (2) Efficiency EDR2, and (3) Total EDR2 (§150.1(b)1). For more information, see Chapter 8.
E. Additions and Alterations:
1. An exception was added that not require junior accessory dwelling units (JADUs) that are classified as additions to an existing building to meet the whole-building mechanical ventilation requirements. JADUs are dwelling units that are no more than 500 square feet and contained entirely within an existing single-family building,
2. New language clarifying when mechanical ventilation requirements apply to alterations.
3. Ceiling insulation in additions 700 square feet or less must meet R-38 in Climate Zones 1, 2, 4, and 8–16 and R-30 in Climate Zones 3 and 5–7.
4. Expand the cool roof requirements for steep-sloped roof replacements to Climate Zones 4 and 8–9. The allowable exceptions were also revised.
5. Expand the cool roof requirements for low-sloped roof replacements to Climate Zones 4, 6–12, and 14. The allowable exceptions were also revised.
6. Add a new requirement for roof deck insulation for low-sloped roof replacements in Climate Zones 1, 2, 4, and 8–16. R-14 continuous roof deck insulation or and equivalent assembly roof assembly U-factor of 0.039 is required. Various exceptions to this requirement are allowed.
7. New language modifying when replacement electric resistance space heating equipment is allowed.
8. Reduce the duct sealing target for altered duct- and space-conditioning systems from 15 percent to 10 percent of total duct leakage in all climate zones.
9. Increase the prescriptive duct insulation from R-6 to R-8 in Climate Zones 1–2, 4, 8–10, and 12-13.
10. Reduce the 40-foot trigger for prescriptive duct sealing and insulation to 25 feet for altered systems. Eliminate the minimum length requirement for additions and require duct sealing whenever an existing duct system is extended to serve an addition.
11. Add a prescriptive requirement for insulation and sealing in vented attics for altered ceilings or when an entirely new or complete replacement duct system is installed in a vented attic. The requirements apply in all climate zones except 5 and 7. Various exceptions to this requirement are allowed.
12. New doors that result in an increase in exterior door area must meet the newly constructed building requirements of a maximum U-factor of 0.20.