How many BTU per hour is 1 horsepower?

One mechanical horsepower equals 2544.43 BTU per hour. This is derived from 1 hp = 745.69987 watts and 1 watt = 3.41214 BTU/hr, giving 745.69987 × 3.41214 ≈ 2544.43 BTU/hr.

What type of horsepower does this tool use?

This tool uses mechanical (imperial) horsepower, the US standard for engines, motors, and HVAC equipment. Mechanical hp = 745.69987 W. Electrical hp (746 W) and metric PS (735.49875 W) differ slightly but the difference is under 1.5% for most practical purposes.

Why is BTU/hr used instead of watts for HVAC?

BTU/hr is the traditional US unit for heating and cooling capacity. HVAC ratings, furnace output, and air conditioner sizing have historically used BTU/hr in North America. Watts are the SI standard used elsewhere and in electrical engineering.

How do I convert BTU/hr back to horsepower?

Divide the BTU/hr value by 2544.43. For example, 10,000 BTU/hr ÷ 2544.43 ≈ 3.93 hp. Use the reverse field in this tool for quick lookups.

How does a 3 hp HVAC compressor compare in BTU/hr?

3 hp × 2544.43 = 7,633 BTU/hr. This is less than a 1-ton unit (12,000 BTU/hr), so a 3 hp motor running a compressor at full load produces around 7,600 BTU/hr of mechanical work — cooling capacity will also depend on refrigerant efficiency (COP).

Is this conversion exact?

It is exact to six significant figures. The factor 2544.43 BTU/hr per mechanical hp is derived from internationally accepted definitions of the watt and BTU, matching IEEE and ASHRAE standards for engineering use.

Horsepower to BTU per Hour Converter

Enter horsepower to instantly get the equivalent BTU per hour — useful for sizing HVAC, furnaces, and heating equipment.

Convert Horsepower

Horsepower (hp)

Mechanical (imperial) horsepower

BTU per Hour (BTU/hr)

Conversion Formula

BTU/hr = hp × 2544.43

1 mechanical hp = 745.69987 W × 3.41214 BTU/(W·hr) = 2544.43 BTU/hr

Enter a value above to see the result

Common Equipment Reference

Equipment	HP	BTU/hr
Small fan motor	0.5	1,272
Small pump motor	1	2,544
Residential HVAC blower	2	5,089
AC compressor (small)	5	12,722
Commercial AC unit	10	25,444
Rooftop HVAC unit	25	63,611
Industrial chiller	100	254,443

Click any row to load the HP value into the converter.

Summary

This tool converts mechanical horsepower to BTU per hour using the exact factor of 1 hp = 2544.43 BTU/hr. It supports single-value and bulk conversion, making it practical for engineers and contractors sizing HVAC equipment, furnaces, boilers, or any heating system where power specs are listed in horsepower but load calculations require BTU/hr.

How it works

Enter a horsepower value in the input field.
The tool multiplies it by 2544.43, the exact conversion factor for mechanical horsepower.
The BTU per hour result appears instantly.
Use the reverse field to convert BTU/hr back to horsepower.
A reference table lists common equipment ratings in both units for quick lookup.

Use cases

Size a furnace or boiler when the motor rating is listed in horsepower.
Convert HVAC compressor specs from hp to BTU/hr for load calculations.
Cross-check equipment datasheets that mix horsepower and BTU/hr ratings.
Estimate heating output of an engine or motor for industrial process design.
Compare power ratings between American and international HVAC standards.
Convert pump motor horsepower to BTU/hr for thermal load analysis.

Frequently Asked Questions

Last updated: 2026-06-19 · Reviewed by Nham Vu