Heating Calculator
Estimate the heating capacity needed for a space.
How It Works
BTU = Area × 30 × (Ceiling ÷ 8) × Climate factor × Insulation factor.
Example
800 sq ft in a cold climate with excellent insulation: 800 × 30 × 1.3 × 0.9 = 28,080 BTU.
Frequently Asked Questions
Why is the heating base higher than cooling?
Heating must overcome outdoor cold, so it typically needs more capacity per square foot — roughly 30 BTU/sq ft.
What is the climate factor?
A multiplier for your region: mild 0.8, moderate 1.0, cold 1.3. Cold climates need more heating.
Does insulation really matter?
Yes — well-insulated homes need dramatically less heating capacity than drafty ones.