HVAC capacity converter
BTU Calculator
Convert cooling or heating capacity between BTU/h, watts, kilowatts, and refrigeration tons.
Capacity conversion
Convert BTU/h
Enter one rated capacity to see equivalent units.
How this calculator works
HVAC capacity is commonly labeled in BTU per hour (BTU/h), while equipment literature may use watts, kilowatts, or refrigeration tons. This calculator converts those capacity units from a single normalized BTU/h value. It does not estimate a building load or an appliance's electrical input.
Formula
kW = BTU/h ÷ 3,412.141633
RT = BTU/h ÷ 12,000
Variables
| Term | Meaning | Unit |
|---|---|---|
| BTU/h | Heat-transfer rate or HVAC capacity | British thermal units per hour |
| W | Equivalent rate in SI power units | Watts |
| RT | Refrigeration capacity rating | Refrigeration tons |
Example
- Enter 12,000 and select BTU/h.
- The calculator returns 3,516.85 W or 3.517 kW.
- It also returns 1 refrigeration ton.
Frequently asked questions
Is BTU/h the same as watts?
Both express a rate of energy transfer, but they use different unit systems. One BTU/h equals about 0.29307107 W.
Does 12,000 BTU/h mean an air conditioner uses 3,517 watts of electricity?
No. It means the unit has about 3,517 W of cooling capacity. Electrical input depends on the equipment efficiency and operating conditions.
Can this tool size an air conditioner for my room?
No. Correct equipment sizing requires a load calculation that accounts for construction, climate, solar gains, ventilation, occupancy, and more.