Horsepower to BTU Per Hour (hp to BTU/h)
1 horsepower equals 2,544.433578 BTU per hour (rounded).
How to convert horsepower to BTU per hour
To convert horsepower to BTU per hour, multiply the number of horsepower by 2,544.433578. The factor is rounded to 10 significant digits. To go the other way, multiply BTU per hour by 0.0003930147789 (rounded).
BTU per hour = horsepower × 2,544.433578
Example: 10 horsepower = 25,444.33578 BTU per hour.
Several different horsepower units exist. This site lists mechanical (745.7 W), metric (735.5 W) and electrical (746 W) horsepower separately.
About these units
Horsepower (hp)
The mechanical horsepower: 550 foot-pounds per second, about 745.7 watts. James Watt coined it to compare steam engines with draft horses.
Horsepower was a sales pitch before it was a unit. Late in the 18th century the Scottish engineer James Watt adopted the term to compare the output of steam engines with the draft horses they replaced. His 1782 experiments found that a brewery horse could produce 32,400 foot-pounds-force per minute, and in 1783 he and Matthew Boulton standardized the figure at 33,000 foot-pounds-force per minute. Customers could then be told how many horses an engine would replace.
That figure works out to 550 foot-pounds-force per second, or about 745.7 watts: the power needed to lift 550 pounds by one foot in one second. Several cousins exist, including metric horsepower and electrical horsepower, defined as exactly 746 W. Car ratings added more confusion. Early British taxable horsepower was a formula based on bore and cylinder count, not measured output, and American ratings before 1972 used SAE gross brake horsepower, measured without accessories. In the European Union, horsepower may be used only as a supplementary unit under Directive 80/181/EEC, in force from 1 January 2010.
1 horsepower = 745.6998716 watts (approximately).
Sources: Wikipedia: Horsepower; Wikipedia: Metric horsepower
BTU Per Hour (BTU/h)
About 0.293 watts. The rating of air conditioners, furnaces and heaters in the US.
Btu per hour inherits its history from the British thermal unit, which a 1942 note in the journal Nature said apparently originated in the United States and was later adopted in Great Britain. The Btu was defined as the heat needed to raise one pound of liquid water by one degree Fahrenheit at a constant pressure of one atmosphere. Because water's heat capacity varies slightly with temperature, several versions exist, differing by up to 0.5 percent, so the unit has never been quite as tidy as the joule.
Dividing it by time gives a power unit used mainly in North America for heating and cooling equipment, and in the UK mostly for air conditioning. One watt is about 3.412 Btu/h, and one horsepower is about 2,544 Btu/h. Thousands of Btu per hour are often written MBH. Air conditioning capacity is often given in tons, where one ton of cooling is 12,000 Btu/h, about 3.52 kW, the rate needed to freeze one short ton of water into ice in 24 hours.
1 BTU per hour = 0.2930710702 watts (approximately).
Sources: Wikipedia: British thermal unit; Wikipedia: Watt
Related conversions
- BTU per hour to horsepower (reverse)
- Horsepower to watts
- Horsepower to kilowatts
- Horsepower to megawatts
- Horsepower to gigawatts
- Horsepower to metric horsepower
- Horsepower to milliwatts
- Horsepower to electrical horsepower
- Horsepower to foot-pounds per second
- Horsepower to tons of refrigeration
- Horsepower to kilocalories per hour
- Horsepower to calories per second
- Horsepower to ergs per second
- Watts to BTU per hour
- Kilowatts to BTU per hour
- Megawatts to BTU per hour
- Gigawatts to BTU per hour
- Metric horsepower to BTU per hour
See all power units.