Convert power units — watts, kilowatts, horsepower, BTU/hr.
| Unit | Name | Value |
|---|---|---|
| W | Watt | 0.293071 |
| kW | Kilowatt | 0.000293071 |
| MW | Megawatt | 2.93071e-7 |
| hp | Horsepower (mech) | 0.00039301462 |
Formula: Horsepower = BTU/hr × 0.000393
Multiply any btu/hr value by 0.000393 to get horsepower.
Reverse: BTU/hr = Horsepower × 2544
Common btu/hr values — factor: 1 BTU/hr = 0.000393 hp
| BTU/hr (BTU/hr) | Horsepower (hp) | Context |
|---|---|---|
| 100 BTU/hr | 0.0393 hp | Small heater element |
| 500 BTU/hr | 0.1965 hp | Hair dryer low |
| 1,000 BTU/hr | 0.393 hp | Small space heater |
| 3,412 BTU/hr | 1.341 hp | 1 kW equivalent |
| 5,000 BTU/hr | 1.965 hp | Small window AC |
| 1e+04 BTU/hr | 3.93 hp | Medium window AC |
| 1.2e+04 BTU/hr | 4.716 hp | 1 ton AC |
| 1.8e+04 BTU/hr | 7.074 hp | 1.5 ton AC |
| 2.4e+04 BTU/hr | 9.432 hp | 2 ton AC |
| 3.6e+04 BTU/hr | 14.15 hp | 3 ton AC |
| 6e+04 BTU/hr | 23.58 hp | 5 ton central AC |
| 100,000 BTU/hr | 39.3 hp | Home furnace |
| 500,000 BTU/hr | 196.5 hp | Commercial HVAC |
| 1,000,000 BTU/hr | 393 hp | Large industrial |
| 1.000e+09 BTU/hr | 393,000 hp | Power plant |
1 BTU/hr = 0.000393 hp. Memorize for instant estimates.
Use 0 as a quick mental multiplier.
Multiply result by 2544 to recover the original BTU/hr value.
Sizes residential and commercial heating and cooling systems in BTU/hr.
Interprets AC unit capacity — '12,000 BTU/hr = 1 ton' for room sizing.
Verifies furnace and AC output ratings in BTU/hr meet local building codes.
Rates boiler output and heat exchanger capacity in BTU/hr.
Calculates heating and cooling loads for buildings in BTU/hr for ASHRAE compliance.
Selects gas appliances, furnaces, and water heaters rated in BTU/hr.
BTU/hr (British Thermal Units per hour) is the Imperial unit of power used in heating, ventilation, and air conditioning (HVAC). One BTU is the heat needed to raise 1 pound of water by 1°F; divided by an hour gives a power rate equal to 0.293071 watts.
HVAC equipment is universally rated in BTU/hr in the United States: window air conditioners range from 5,000 to 25,000 BTU/hr; central AC systems from 18,000 to 60,000 BTU/hr. Natural gas furnaces are rated in BTU/hr output.
Interesting fact: 12,000 BTU/hr = 1 'ton of refrigeration' — the cooling power needed to melt one ton of ice in 24 hours. This legacy unit still defines residential AC capacity in the US, where a 'one-ton' unit is a 12,000 BTU/hr air conditioner.
Horsepower (hp) was defined by James Watt in the 1780s to quantify steam engine output in terms familiar to mine operators who used horses to pump water. One mechanical horsepower equals 550 foot-pounds per second = 745.7 watts.
Horsepower remains the dominant power rating for vehicle engines in the United States, Canada, and the UK. Car engines range from 70 hp (economy) to 700+ hp (sports cars). Electrical motors, pumps, and industrial equipment are often rated in both kW and hp.
Interesting fact: There are multiple horsepower definitions: mechanical hp (745.7 W), metric hp (735.5 W), electrical hp (746 W), and boiler hp (9,810 W). Most automotive usage refers to mechanical hp. A racehorse at full gallop produces about 14–15 hp peak, not 1 hp.
Converting btu/hr to horsepower is common across electrical engineering, automotive, and HVAC industries. Different sectors use different power units — watts and kilowatts in electrical systems, horsepower in automotive and industrial machinery, and BTU/hr in heating and cooling — making accurate conversion essential for international equipment specifications and cross-disciplinary engineering.
Quick reference: 5 BTU/hr = 0.001965 hp and 10 BTU/hr = 0.00393 hp. Reverse: 1 hp = 2544 BTU/hr. Exact factor: 1 BTU/hr = 0.000393 hp.
All conversions use IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.