Table 2. Opaque Wall U-Values (Uw) for Attached and Multi-Family Buildings (excerpted from ICC 2003)
Heating Degree Days Base 65 (HDD65) From Nearest Location
7,100–8,999 3,000–7,099 2,800–2,999 2,600–2,799 < 2,600
U w A i r t o A i r , I n c l u d e s F r a m i n g ( B t u / h · f t 2 · ° F )
0.064 0.076 0.085 0.100 0.120 0.140
Table 3. Vertical Fenestration U-Values (UF) and SHGC
HDD65 From Nearest Location Based on TMY3 Data*
Summary statistics for typical meteorological year (TMY3) sites can be found in the BA Analysis
UF Air to Air,
( ) u Bt /h·ft2·°F Includes Framing and Sash
U-value of an insulated floor above a vented crawl space or other unconditioned space shall be as specified in Figure 1 (excerpted from ICC 2003). The ventilation rate shall be the same in the Benchmark as the Prototype, regardless of whether the ventilation is natural or fan induced.
U-value of insulated walls in an unvented crawl space shall be as specified in Figure 2 (excerpted from ICC 2003). This U-value represents the combined effect of wall components and the surface air film, but it does not include adjacent soil.
U-value of insulated basement walls shall be as specified in Figure 3 (excerpted from ICC 2003), and the insulation shall be located on the interior surface of the walls. This U-value represents the basement wall assembly, including the surface air film, but it does not include ground effects.
R-value and depth of slab edge insulation for slab-on-grade construction shall be as specified in Figure 4 (excerpted from ICC 2003). This R-value is for rigid foam insulation and does not include the slab itself or ground effects.
U-value of insulated roof/ceiling shall be as specified in Figure 5 (excerpted from ICC 2003), except for cathedral ceilings which shall have a U-value of 0.036 in all locations with more than 2500 heating degree-days. If the Prototype includes an attic, the Benchmark shall have an unconditioned attic with insulation at the attic floor.