Convert BTU per Hour to Foot-Pound per Second (BTU/h → ft·lbf/s)
BTU per hour is the standard rating for American heating, air-conditioning, and refrigeration system capacity.
BTU per Hour to Foot-Pound per Second Conversion Table
10 common values| BTU per Hour | Foot-Pound per Second |
|---|---|
| 1 BTU/h | 0.216158 ft·lbf/s |
| 5 BTU/h | 1.080791 ft·lbf/s |
| 10 BTU/h | 2.161581 ft·lbf/s |
| 50 BTU/h | 10.807906 ft·lbf/s |
| 100 BTU/h | 21.615813 ft·lbf/s |
| 500 BTU/h | 108.07906 ft·lbf/s |
| 1,000 BTU/h | 216.15813 ft·lbf/s |
| 5,000 BTU/h | 1,080.7906 ft·lbf/s |
| 10,000 BTU/h | 2,161.5813 ft·lbf/s |
| 50,000 BTU/h | 10,807.906 ft·lbf/s |
How to Convert BTU per Hour to Foot-Pound per Second Manually
Step by StepConverting BTU per hour to foot-pounds per second is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.
- 1Take your value in BTU per hourStart with the number of BTU per hour (BTU/h) you want to convert.
- 2Multiply by 0.216158The conversion factor from BTU/h to ft·lbf/s is 0.216158. Multiply your value by this number.
- 3Read the result in foot-pounds per secondThe result is your value in foot-pounds per second (ft·lbf/s).
Formula
Multiply the value in BTU per hour by 0.216158. For the reverse direction, multiply by 4.626243.
ft·lbf/s = BTU/h × 0.216158BTU/h = ft·lbf/s × 4.626243Tips
Use these in everyday conversions- 1 BTU/h = 0.293 W; 3412 BTU/h = 1 kW.
- 12,000 BTU/h = 1 ton of refrigeration.
- Tons of AC rating: divide BTU/h by 12,000.
Common Mistakes
Avoid these- Confusing BTU (energy) with BTU/h (power) — same abbreviation in ads.
- Mixing tons of AC and tons of weight — different concepts.
- Using BTU/h for non-HVAC contexts.
About BTU per Hour and Foot-Pound per Second
What is the BTU per Hour?
BTU per hour (BTU/h or BTUh) is the standard rating for American heating, air-conditioning, and refrigeration system capacity. A window air conditioner is typically 5,000–12,000 BTU/h, central residential AC ranges 24,000–60,000 BTU/h, and commercial chillers reach 100,000–1,000,000+ BTU/h. The unit's persistence in HVAC reflects American engineering tradition: it directly links cooling/heating capacity to the BTU energy unit familiar in gas-fired equipment. 12,000 BTU/h equals 'one ton of refrigeration' (a unit derived from the heat needed to melt 1 ton of ice in 24 hours), so AC sizes are sometimes given in 'tons' (a 3-ton AC = 36,000 BTU/h). BTU/h relates to the watt (1 W ≈ 3.412 BTU/h), the kilowatt (1 kW ≈ 3,412 BTU/h), and the ton of refrigeration (12,000 BTU/h = 1 ton). Outside the US, kW is dominant for HVAC capacity.
- US air conditioners and heat pumps
- US furnace and boiler ratings
- Some industrial heat-exchanger specs
Small window AC: 5000 BTU/h. Central AC: 24,000 BTU/h. Home furnace: 80,000 BTU/h.
What is the Foot-Pound per Second?
The foot-pound per second (ft·lb/s) is the American mechanical-power unit, used in engineering and machine-rating contexts. James Watt's original definition of 1 horsepower was 33,000 ft·lb/min = 550 ft·lb/s, so the foot-pound per second is the granular American power unit underlying horsepower calculations. It is rare in everyday use (kW or hp dominate American power specifications) but appears in engineering thermodynamics textbooks, mechanical-design calculations, and ballistics-energy contexts. The ft·lb/s relates to the watt (1 ft·lb/s ≈ 1.356 W), horsepower (550 ft·lb/s = 1 hp), and the BTU per hour (1 ft·lb/s ≈ 4.626 BTU/h). It is part of the legacy US customary unit system that retains a foothold in mechanical engineering despite metric advancement.
- Older US mechanical-engineering calculations
- Some US physics textbooks
- Classical-mechanics problems
Largely historical; modern specs use W or hp.