BTU Calculator
Heating and cooling capacity a room needs.
Enter your values
Results update instantly as you type — no submit needed.
Results
- Cooling capacity needed
- 8,000 BTU/hr
- In tons of cooling
- 0.67
- Heating capacity (rough)
- 12,000 BTU/hr
- In kilowatts
- 2.34 kW
Quick answer
A rough baseline is 20 BTU per square foot for cooling, adjusted for ceiling height, sunlight and insulation quality.
BTU ≈ area × 20 × adjustment factors
How to use the BTU Calculator
- 1Enter the room area and ceiling height.
- 2Pick sun exposure and insulation quality.
- 3Read the BTU capacity to shop for.
Frequently asked questions
Is a bigger unit better?
No. An oversized AC short-cycles, cooling fast without removing humidity, which leaves the room clammy.
How many BTU is a ton?
12,000 BTU per hour — the rate at which a ton of ice melts in 24 hours.