Btu, BTU/h, and watts are not the same thing
A Btu is an amount of energy. BTU/h is a rate of heat transfer, so it is the form commonly used for an air conditioner, heat pump, or heating-capacity label. A watt is also a rate; converting BTU/h to watts compares thermal rates. It does not tell you how many electrical watts a piece of equipment will consume.
Core capacity conversions
kW = BTU/h ÷ 3,412.141633
BTU/h = kW × 3,412.141633
RT = BTU/h ÷ 12,000
Here, RT means refrigeration tons. The 12,000 BTU/h relationship is a capacity convention. Keep the time basis: a Btu total cannot be converted to BTU/h until a time period is defined.
Worked example: 24,000 BTU/h
| Step | Calculation | Result |
|---|---|---|
| Refrigeration tons | 24,000 ÷ 12,000 | 2 RT |
| Thermal watts | 24,000 × 0.29307107 | 7,033.7 W |
| Thermal kilowatts | 7,033.7 ÷ 1,000 | 7.03 kW |
The 7.03 kW result is thermal capacity. It is not a compressor electrical-input rating and should not be used to estimate electrical consumption without equipment performance data.
Formula mistakes to avoid
- Using the Btu energy definition where a BTU/h capacity rate is required.
- Calling thermal kW and electrical kW the same value.
- Using nominal tonnage as delivered capacity at every outdoor condition.
- Converting a capacity label and treating the result as a building-load calculation.
Use the conversion after the load is known
First estimate or calculate the heating or cooling load with the relevant building, climate, ventilation, solar, and internal-gain inputs. Then use these formulas to compare the load with equipment capacity data. For a room planning estimate, the result still needs verification against the actual system and applicable design method.
Convert a value without manual arithmetic
Enter a BTU/h, watt, kilowatt, or ton value and compare the equivalent thermal rates.
BTU CalculatorFAQ
Does BTU/h equal electrical watts?
No. They can be converted as rates of thermal power, but equipment electrical input depends on efficiency, operating conditions, and product data.
Why use refrigeration tons?
Tons are concise HVAC capacity shorthand. Use BTU/h or kW when a more precise capacity value is needed.