Energy & HVAC

BTU Calculator

Estimate a building's heat loss in BTU per hour from wall, window, ceiling and floor R-values and air leakage, plus heating energy over time.

Room BTU Calculator

Air Conditioner Efficiency Savings Calculator

Compare air conditioner running costs by SEER2 or SEER rating: yearly savings, electricity saved and payback on the price difference.

Heat Pump vs Furnace Operating Cost Calculator

Ductwork Sizing Calculator

Size supply ducts and the main trunk from each room's CFM with the equal-friction method, with air velocity and rectangular duct equivalents.