Garage Heater Calculator
Estimate preliminary garage-heater capacity from room volume, temperature rise, insulation factor, door openings, reserve and heater efficiency.
Default project preview
35,000 BTU/h
Base heat output
24,883 BTU/h
Door-opening factor
8%
Garage volume
5,184 ft³
Equivalent electric input
9.53 kW
Calculator
Build the material order
Your order will appear here
Enter the project details and calculate a rounded material estimate.
Methodology
Transparent calculation
BuildMeter converts every input to a consistent internal unit, applies the selected allowance, and rounds products up to whole purchasable units.
Base heat output = room volume × temperature rise × heat-loss factor. Door-opening and reserve allowances are applied, then output is divided by heater efficiency.
FAQ
Garage Heater Calculator questions
What heat-loss factor should I use?+
The factor represents construction and exposure. A proper heat-loss calculation is more reliable than any generic factor.
Why do garage doors affect heater size?+
Large door openings rapidly replace warm indoor air with outdoor air.
Can a combustion heater be used without venting?+
Only equipment specifically approved for the installation and used exactly as required. Combustion and carbon-monoxide risks require professional attention.