ENERGY MODEL FOR OFFICE IN BASEMENT

1. C-factor is similar to U-factor, except that the air film is excluded since it in contact with the ground. If the U-value input of your software does not include air film resistance, then the C-factor would be entered directly. If the U-value does include air film resistance, you would add the interior vertical surfaces air film (R-0.68) to the inverse of the C-factor to determine the overall R-value, and then take the inverse to determine the U-value. In either case it should be designated as an underground wall in the software. 2. Table A3.1C is used to determine the U-factor, C-factor, R-value, and heat capacity (HC) of various standard concrete block wall constructions. U-factor is 1/R_u and includes air film resistances, while C-factor is 1/R_c and does not include air film resistances as discussed above.  3. F-factor is the perimeter heat loss factor for slab-on-grade floors, expressed per length of building perimeter rather than per surface area as with a U-factor. The slab-on-grade F-factor accounts for the impact of the slab and the earth under the slab. If the energy model cannot reflect an F-factor, model the Baseline slab-on-grade floor as a six inch concrete slab over earth with a soil conductivity of 0.75 Btu/h-ft-F in accordance with A6.1.