Capacity units
Cooling or heating capacity: kW to BTU/h and tons of refrigeration
- where
- capacity (BTU/h)
- capacity (kW)
- capacity (tons of refrigeration)
Explain this equation
Converts a cooling or heating capacity in kW into BTU per hour and tons of refrigeration. Use it to compare equipment rated in different units.
P is the capacity in kW and the 1000 changes it to watts. 0.29307107 is the number of watts in one BTU per hour. 3.5168528 is the number of kW in one ton of refrigeration.
One ton of refrigeration is defined as 12 000 BTU per hour, the cooling from melting a short ton of ice in a day, so both conversions are fixed factors.
Sense check: 3.5 kW is about 12 000 BTU/h, one ton. 1 kW is about 3412 BTU/h.
Watch out: the capacity is the heat moved, not the electricity used.
Converts a capacity in kW to BTU/h and tons of refrigeration, for comparing UK, US and Asian equipment data.
Enter your values to see the result.
Good to know
1 BTU/h (international table BTU) = 0.29307107 W. One ton of refrigeration = 12 000 BTU/h = 3.5168528 kW, the rate of cooling from melting a short ton of ice in 24 hours. Split units sold as “12 000 BTU” are therefore about 3.5 kW.
Common mistake
Confusing cooling capacity with electrical input. A 3.5 kW cooling unit typically draws around 1 kW of electricity.
Limits
Pure unit conversion. Rated capacity depends on test conditions (indoor and outdoor temperatures).
Sources
Results are calculations from the published methods and figures shown, and depend on the data you enter. Follow the equipment manufacturer’s data, CIBSE guidance, BS EN 378, the F-gas Regulations and your company procedures. Refrigerant work needs the correct F-gas certification.