window caulk savings calculations
How your savings are calculated
Step 1 determine infiltration2.355 crack coefficient x 16 ft x .01^.67 inches of water = 1.7 CFM without weatherization 1.536 crack coefficient x 16 ft x .01^.67 inches of water = 1.1 CFM with weatherization |
Step 2 determine savings1.7 CFM without weatherization - 1.1 CFM with weatherization = 0.6 CFM |
Step 3 determine cooling energy0.081 density of air (lb/cu ft) x 0.240 heat capacity of air (BTU/lb °F) x 2008 CDD (°F day) x 0.6 CFM x 24 hrs/day x 60 min/hr = 33,727 BTUs |
Step 4 determine heating energy0.081 density of air (lb/cu ft) x 0.240 heat capacity of air (BTU/lb °F) x 2914 HDD (°F day) x 0.6 CFM x 24 hrs/day x 60 min/hr = 48,944 BTUs |
Step 5 determine cooling utility used cool air33,727 BTUs / 15 SEER (BTU/W hr) / 1,000 W/kW = 2.2 kWh per year |
Step 6 determine heating utility used heat air48,944 BTUs / 8.2 HSPF (BTU/W hr) / 1,000 W/kW = 6.0 kWh per year |
Step 7 determine cooling savings2.2 kWh x $0.118 = $0.27 per year |
Step 8 determine heating savings6.0 kWh x $0.118 = $0.70 per year |
Step 9 determine total savings2.2 kWh cooling + 6.0 kWh heating = 8.2 kWh total savings per year $0.27 cooling + $0.70 heating = $0.97 total savings per year 8.2 kWh x 15 = 123.3 kWh lifetime savings $0.97 x 15 = $14.54 lifetime savings |