BTU/h is a capacity rate
A Btu is a unit of energy. HVAC equipment labels normally use BTU per hour (BTU/h), which is a rate of heat transfer. The same capacity can be written in watts or kilowatts because watts are also rates of energy transfer.
Why cooling capacity is quoted in tons
In refrigeration and air conditioning, one refrigeration ton is conventionally 12,000 BTU/h. The U.S. Department of Energy uses this relationship when expressing chiller capacity.
Capacity is not electrical input
A 12,000 BTU/h air conditioner has 12,000 BTU/h of rated cooling capacity. Its electrical consumption is a separate value affected by efficiency and operating conditions. Do not use capacity conversion alone to estimate electrical demand or utility cost.
Convert a capacity rating
Use the BTU Calculator to convert BTU/h, watts, kilowatts, and refrigeration tons from the same capacity value.
Open the BTU CalculatorWhere the conversion comes from
NIST Federal Standard 376B lists the International Table Btu as 1.055056 kilojoules and identifies the watt as the SI unit for power. Dividing Btu energy by one hour gives approximately 0.29307107 W per BTU/h.
Frequently asked questions
What is 24,000 BTU/h in refrigeration tons?
24,000 BTU/h is 2 refrigeration tons using the 12,000 BTU/h-per-ton convention.
Is a kW of cooling the same as a kW of electricity?
No. A kW of cooling is capacity. A kW of electricity is input power. Their relationship depends on equipment efficiency.