Subsection R408.2 - Additional efficiency package optionsAdditional efficiency package options for compliance with Section R401.2.1 are set forth in Sections R408.2.1 through R408.2.5.
R408.2.1Enhanced envelope performance option. The total building thermal envelope UA, the sum of U-factor times assembly area, shall be less than or equal to 95 percent of the total UA resulting from multiplying the U-factors in Table R402.1.2 by the same assembly area as in the proposed building. The UA calculation shall be performed in accordance with Section R402.1.5. The area-weighted average SHGC of all glazed fenestration shall be less than or equal to 95 percent of the maximum glazed fenestration SHGC in Table R402.1.2.R408.2.2More efficient HVAC equipment performance option. Heating and cooling equipment shall meet one of the following efficiencies:1. Greater than or equal to 8.5 HSPF2 and 16 SEER2 for ductless heat pumps and 8.5 HSPF2 and 15.2 SEER2 for ducted heat pumps.2. Greater than or equal to 3.5 COP ground source heat pump. For multiple cooling systems, all systems shall meet or exceed the minimum efficiency requirements in this section and shall be sized to serve 100 percent of the cooling design load. For multiple heating systems, all systems shall meet or exceed the minimum efficiency requirements in this section and shall be sized to serve 100 percent of the heating design load.
R408.2.3Reduced energy use in service water-heating option. The hot water system shall meet one of the following efficiencies: 1. Greater than or equal to 2.0 EF electric service water-heating system.2. Greater than or equal to 0.4 solar fraction solar water-heating system.R408.2.4More efficient duct thermal distribution system option. The thermal distribution system shall meet one of the following efficiencies: 1. 100 percent of ducts and air handlers located entirely within the building thermal envelope.2. 100 percent of ductless thermal distribution system or hydronic thermal distribution system located completely inside the building thermal envelope.780 CMR, ch. 51, ch. 4, R405, R408.2
Amended by Mass Register Issue 1532, eff. 10/11/2024.