California Tax Credit Allocation Committee

Assumptions for Non-Verifiable Existing Conditions

Measure Assumption Rationale
Floor If insulation exists assume R -19, if no insulation exists assume R-0 R-19 has been the standard level of insulation since the advent of Title 24.
Wall* If insulation exists assume R 11, if no insulation, assume R- 0 1985 was the approximate date when R-11 wall insulation requirements for MF buildings were first effectively enforced.
Ceiling Measure insulation depth and refer to CEC’s insulation R value table n/a
Windows default table for Title 24 2008 based on frame and glazing type n/a
Water Heater – tank type 0.52 Energy Factor The Minimum code threshold was 0.52 from 1986-2005. We assume pre-1986 WHs have been replaced since then.
Water Heater – boiler 0.70 AFUE Some older boilers might be slightly less efficient. This represents boilers from 1970s-80s.
Water Heater - tankless 0.75 EF Applies CEC de-rating to older tankless water heaters.
Wall furnace 0.45 AFUE Average wall heater efficiency in the 1980s was 0.60-0.65, but older ones about 0.45.
Floor furnace 0.45 AFUE Average floor heater efficiency in the 1980s was 0.60-0.65, but older ones about 0.45.
Ducted central furnace 0.72 and 30% duct leakage The minimum code threshold for a ducted central furnace has been code since mid-1980s. Research in early 1990s, showed typical leakage of ~30%
Air Conditioning 5.0 SEER The code standard SEER in the 1970 and early 1980s was 6.8, but with normal degradation of systems, SEER 5 is appropriate.
Heat pump 1.32 COP  

*Wall Insulation can be verified by two methods; Using an IR Camera to verify all exterior walls have insulation in all elevations, or by following section A-2 of the 2008 HERS Technical Manual Appendix A, ACM section 3.5.2 Exterior Walls. (Determine type and thickness of existing insulation and resultant U-factor). The verification procedures in the HERS Appendix must also be conducted on all exterior wall elevations.