BTU to Kilowatts (BTU/hr to kW) Converter

The BTU to Kilowatts Converter bridges two of the most commonly used power units in the built environment: the British Thermal Unit per hour (BTU/hr), the dominant unit for heating and cooling equipment in North America, and the kilowatt (kW), the universal SI unit of power used in electrical engineering, European HVAC standards, and energy efficiency calculations. This tool is indispensable for HVAC engineers, electricians, energy auditors, building system designers, and facility managers who work across equipment specifications that use different unit systems.

The British Thermal Unit (BTU) is defined as the quantity of heat required to raise the temperature of one pound of water by one degree Fahrenheit at a specified temperature and pressure. Since BTU is a measure of energy (like the joule), the common unit for power in HVAC is the BTU per hour (BTU/hr) — the rate of heat transfer per unit time. At sea level with specific thermodynamic conditions, 1 BTU = 1055.06 joules, making 1 BTU/hr = 1055.06 J/hr = 0.29307 W. Therefore, the conversion factor is: 1 kW = 3412.14 BTU/hr, or equivalently, 1 BTU/hr = 0.000293071 kW.

This conversion appears constantly in electrical and HVAC practice. When an electrician installs a resistance heater rated at 5000 BTU/hr, they need to know the wattage (1465 W) to size the circuit breaker and wire gauge. When a building energy model specifies cooling loads in BTU/hr, the mechanical engineer must convert to kW to size the chiller and its electrical supply. When comparing a US-market air conditioner (rated in BTU/hr) to a European unit (rated in kW), this conversion makes direct comparison possible.

Common BTU-to-kW reference points that professionals memorize: 3,412 BTU/hr = 1 kW (the fundamental reference); 12,000 BTU/hr = 3.517 kW = 1 ton of refrigeration (the cooling capacity of a standard window AC unit); 100,000 BTU/hr = 29.3 kW (a medium residential gas furnace output); 1,000,000 BTU/hr = 1 MMBTU/hr = 293 kW (often used for large boiler ratings); 1 therm/hr = 100,000 BTU/hr = 29.3 kW.

This converter also calculates tons of refrigeration in the output. One ton of refrigeration equals 12,000 BTU/hr = 3.51685 kW, representing the cooling capacity needed to melt one short ton (2000 lb) of ice in 24 hours. This unit is standard for specifying commercial and industrial cooling equipment, chillers, and refrigeration systems in North America. Central chiller plants for large buildings are commonly specified in both tons and kW, making this three-way conversion (BTU/hr ↔ kW ↔ tons) essential.

In electrical load calculations, the BTU/hr to kW conversion also plays a role in calculating heat gains and cooling loads for data centers and server rooms. NEC Article 645 requires calculating heat dissipation from IT equipment (often specified in BTU/hr on server nameplates) to determine the cooling system capacity, which is then specified in tons or kW for the HVAC contractor. Similarly, infrared heater manufacturers in North America rate their products in BTU/hr while the electrical supply is rated in watts — this tool makes cross-checking specifications straightforward.

This calculator supports bidirectional conversion: enter BTU/hr to get kW, or switch the direction selector and enter kW to get BTU/hr. This flexibility eliminates the need for separate tools when checking both directions of a specification.