The most significant change in the 2019 Building Energy Efficiency Standards affecting residential buildings is the introduction of photovoltaic requirements in the prescriptive standards. There are also significant changes in requirements related to indoor air quality requirements..
The determining factor for whether natural gas is available for newly constructed buildings is if a gas service line can be connected to the site without a gas main extension. For additions and alterations, natural gas is available if a gas service line is connected to the existing building.
Other changes for residential buildings include:
A. Walls with 2x6 framing require R-20 insulation (if wood-framed) or 0.071 maximum U-factor (§150.0(c)2).
B. Fan efficacy requirements change to 0.45 W/CFM for gas furnaces and remain at 0.58 W/CFM for systems that are not gas furnaces (single zone and zonally controlled systems ((§150.0(c)13B and C).
C. Modifications to the indoor air quality requirements of American Society of Heating, Refrigerating, and Air-conditioning Engineers (ASHRAE) 62.2 are included for various building and dwelling unit configurations such as horizontally attached buildings, or central ventilation systems (§150.0(o)1-(o)2).
D. Minimum efficiency reporting value (MERV) 13 (or equivalent) filters are required for heating/cooling systems and ventilation systems (§150.0(m)12).
E. New fan efficacy requirement for small-duct high-velocity forced-air systems (§150.0(m)13D).
A. Adding a prescriptive table (150.1-B) for multifamily buildings (§150.1(c)).
B. Removing the attic/roof Option A with above-deck insulation (§150.1(c)1A).
C. Required wall U-factors in Climate Zones 1-5 and 9-16 are changed from 0.051 to 0.048 in single-family buildings; Climate Zones 6-7 remain at 0.065 (§150.1(c)1B).
D. Added a U-factor requirement for doors (§150.1(c)5).
E. Quality insulation installation (QII) is now a prescriptive requirement for all single-family buildings in all climate zones, and multifamily buildings in all climate zones except Climate Zone 7 (§150.1(c)1E).
F. Added prescriptive options for heat pump water heaters for newly constructed buildings, addition, and alterations (§150.1(c)8, §150.2(a)1D, and §150.2(b)1H).
G. New solar electric generation photovoltaic requirement (§150.1(c)14).
H. New fan efficacy requirements of 0.45 W/CFM for gas furnaces.
All compliance software programs approved by the Energy Commission 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 2019 Residential Alternative Compliance Manual (ACM) Reference Manual.
Compliance requires meeting two components of an Energy Design Rating (EDR): (1) an energy efficiency design rating and (2) a solar electric generation and demand flexibility design rating §150.1(b)1). For more information, see Chapter 8.
A. Changes to the prescriptive requirement for continuous insulation on an existing wall with wood siding; if siding is not removed, only cavity insulation is required (§150.2(a)1).
B. The prescriptive requirement for quality insulation installation (QII) is not required for additions that are 700 square feet or less (§150.2(a)1B).
C. Roof/ceiling insulation and radiant barrier requirements for prescriptive additions with 700 square feet or less follow Option C (R-38 in Climate Zones 1, 11-16, or R-30 and radiant barrier in Climate Zones 2-10) (§150.2(a)1B).
D. More detailed information on additions and alterations is found in Chapter 9.