How Many BTUs to Heat a 20x20 ft Garage?
A 20×20 ft garage with 8-foot ceilings and minimal insulation typically needs 12,000–16,000 BTU/hr to heat effectively.
How to use this tool
- Enter room length, width, and ceiling height in feet.
- Select insulation quality (average is most common).
- The result shows room volume and the recommended heater BTU output.
Calculate the heater BTU output needed to warm a standard two-car 20×20 foot garage workshop in cold climates.
Frequently asked questions
- How many BTU do I need to heat a room?
- Multiply the room volume (ft³) by a factor of 3–5 BTU depending on insulation quality. A 1,440 ft³ room with average insulation needs about 5,760 BTU/hr.
- What size electric heater do I need?
- Divide the BTU requirement by 3.412 to convert to watts. A 5,760 BTU/hr heater is approximately 1,688 watts (about 1.7 kW).