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 thermal capacity to see equivalent units.
How this calculator works
HVAC capacity is commonly labelled in BTU per hour (BTU/h), while equipment literature may use watts, kilowatts, or refrigeration tons. The calculator first normalizes your input to BTU/h and then displays equivalent thermal rates. 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 thermal rate in SI units | Watts |
| RT | Conventional refrigeration capacity rating | Refrigeration tons |
Example
- Enter 12,000 and select BTU/h.
- The calculator returns 3,516.85 W or 3.517 kW of thermal capacity.
- It also returns 1 refrigeration ton.
Result interpretation
Use the result to compare labels that describe the same thermal capacity. Do not read 3.517 kW thermal as electrical consumption. Electrical input varies with equipment efficiency, operating conditions, and the manufacturer’s ratings. For a space-specific capacity question, calculate the load first.
Need an HVAC size estimate?
Start with the HVAC Load Calculator for a transparent preliminary component estimate, then use this converter or BTU to Tons Calculator to compare its capacity units.
Frequently asked questions
Is BTU/h the same as watts?
Both express a rate of energy transfer, but they use different units. 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 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, humidity, and more.