Table 2124: Default values for algorithm terms, Residential Rim Joist Insulation Term Unit Values Source EDC Data Gathering , baseline R-value of rim joist 1 °F-ft2-h/Btu 2.50 Default = , EDC Data R-value of installed spray foam or rigid foam °F-ft2-h/Btu EDC Data Gathering Gathering insulation applied to rim joist L, length of rim joist around the entire insulated EDC Data ft EDC Data Gathering perimeter Gathering EDC Data H, height of insulated rim joist ft EDC Data Gathering Gathering 24, conversion factor hours/day 24 Table 2125 CDD, cooling degree days °F-day 2 Table 2126 HDD, heating degree days °F-day 2 DUA, Discretionary Use Adjustment, adjustment for times when AC is not operating even though None 0.75 3 conditions may call for it 1000, conversion factor Btu/kBtu 1000 EDC Data Gathering Default = 11 (Central , Seasonal Energy Efficiency Ratio of cooling 4 A/C) or system 12 (ASHP) EDC Data Gathering , efficiency of heating system None 4 Table 2127 AF, adjustment factor, accounts for prescriptive None 0.88 5 engineering algorithms overestimating savings EDC Data Gathering , equivalent full-load hours of air conditioning hours 6 Table 2128 Central AC: 0.647 Room AC: 0.30 CF, coincidence factor Decimal 7, 8 ASHP: 0.647 GSHP: 0.647 Insulation in unconditioned spaces (standard crawlspace) is modeled by reducing the degree days to reflect the smaller but non-zero contribution to heating and cooling load.
Table 2124: Default values for algorithm terms, Residential Rim Joist Insulation Term Unit Values Source , baseline R-value of rim joist °F-ft2-h/Btu EDC Data Gathering Default = 2.50 1 , R-value of installed spray foam or rigid foam insulation applied to rim joist °F-ft2-h/Btu EDC Data Gathering EDC Data Gathering L, length of rim joist around the entire insulated perimeter ft EDC Data Gathering EDC Data Gathering H, height of insulated rim joist ft EDC Data Gathering EDC Data Gathering 24, conversion factor hours/day 24 CDD, cooling degree days °F-day Table 2125 2 HDD, heating degree days °F-day Table 2126 2 DUA, Discretionary Use Adjustment, adjustment for times when AC is not operating even though conditions may call for it None 0.75 3 1000, conversion factor Btu/kBtu 1000 , Seasonal Energy Efficiency Ratio of cooling system EDC Data Gathering Default = 11 (Central A/C) or 12 (ASHP) 4 , efficiency of heating system None EDC Data Gathering Table 2127 4 AF, adjustment factor, accounts for prescriptive engineering algorithms overestimating savings None 0.88 5 , equivalent full-load hours of air conditioning hours EDC Data Gathering Table 2128 6 CF, coincidence factor Decimal Central AC: 0.647 Room AC: 0.30 ASHP: 0.647 GSHP: 0.647 7, 8 Insulation in unconditioned spaces (standard crawlspace) is modeled by reducing the degree days to reflect the smaller but non-zero contribution to heating and cooling load.
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