Gas Load Calculations

[kmtswims]

Is there a quick and easy way to do a rough calculation for Gas Load on a building? I am looking to figure out a rough BTU/sf for a building in Conneticut. I want to include a rough calculation for heating the makeup outdoor air as well (say from 10 deg to 70 deg?). This is just a quick estimate and doesn't need to be as in depth as using Trane Trace or anything.

 

[ChrisConley]

Total wall area / R value of walls = Q walls
Total roof area / R value of roof = Q roof
Total window area / R value of window = Q window
Ventilation = 1.08 CFM DeltaT
Add 100MBH for domestic hot water

Add them all together, throw in a safety factor (15-25%) and you should have a rough peak gas load.

If you have more time, there are a lot of free, simple heat loss calculators online. Slantfin has one

http://www.slantfin.com.