Multiply BTU/h by 0.293071
1 BTU equals 1055.06 joules (the precise IT-table value). 1 BTU per hour equals 1055.06 J ÷ 3600 s = 0.293071 W. ConvertBuddy assumes BTU/h when converting BTU to watts, since that is the rated specification on HVAC and combustion equipment. To convert raw BTU (energy, not rate) to joules instead, multiply by 1055.06. Energy and power are different physical quantities — confusing them gives nonsense results for sizing decisions.
BTU and watts both relate to energy, but in different forms. A BTU (British Thermal Unit) is energy — the heat to raise one pound of water by one degree Fahrenheit. A watt is power — energy per unit time, specifically one joule per second.
The conversion most people search for is actually BTU per hour (BTU/h) to watts, which compares heating or cooling rates. Air conditioners, furnaces, gas grills, and water heaters all rate output in BTU/h in the US and in watts or kilowatts in metric markets.
1 BTU/h equals 0.293 watts. A 10,000 BTU/h window AC equals roughly 2.93 kW of cooling capacity.
US window and portable AC units rate cooling in BTU/h. European mini-splits rate in watts or kW. Convert to compare the same model spec across regions or pick the right unit for a room calculated by either local sizing guide.
Gas heaters list output in BTU/h, electric heaters in watts. Convert to evaluate true output capacity, not just sticker spec, when deciding which to install for a given space.
Patio heaters in the US list 40,000-50,000 BTU/h. EU-sold equivalents list 12-15 kW. Convert to confirm the heater handles your patio area before buying internationally.
Inground pool heaters rate 200,000-400,000 BTU/h. Heat pump alternatives rate in kW. Convert to compare operating cost across heater types using a single power unit.
Server rack heat dissipation is given in watts (server PSU draw). HVAC capacity is sold in BTU/h or tons (12,000 BTU/h per ton). Convert to size the cooling solution against the heat load.
12,000 BTU/h equals approximately 3,517 watts.