Convert Watt to BTU per Hour (W → BTU/h)

Converting watts to BTU per hour is straightforward: multiply by the conversion factor. Follow these three steps to do it by hand or in your head.

1. 1
   Take your value in watts

   Start with the number of watts (W) you want to convert.
2. 2
   Multiply by 3.412142

   The conversion factor from W to BTU/h is 3.412142. Multiply your value by this number.
3. 3
   Read the result in BTU per hour

   The result is your value in BTU per hour (BTU/h).

Multiply the value in watts by 3.412142. For the reverse direction, multiply by 0.293071.

• ✓1 W = 1 J/s = 1 V × 1 A (for DC).
• ✓LED lighting: 10× more efficient than incandescent.
• ✓For home appliances, rating × hours used = kWh.

• ✗Confusing watts (power) with joules (energy).
• ✗Assuming "100 W bulb" for LED — old incandescent rating.
• ✗Mixing W with V or A — different quantities.

What is the Watt?

The watt is the SI unit of power, equal to one joule per second (1 W = 1 J/s). Named after Scottish engineer James Watt (1736–1819), whose improvements to the steam engine sparked the Industrial Revolution, the watt unifies mechanical, electrical, and thermal power. A typical LED bulb consumes 8–12 W to produce as much light as a 60-W incandescent bulb. Human resting metabolism is about 80–100 W of heat output, while peak athletic performance reaches 400–1,500 W (briefly). The watt is fundamental in electrical engineering: P = V × I (power = voltage × current). It relates to the kilowatt (1 kW = 1,000 W), the megawatt (1 MW = 10⁶ W), horsepower (1 hp ≈ 745.7 W), and the BTU per hour (1 W ≈ 3.412 BTU/h). Light bulb and appliance ratings, electric motor outputs, and audio amplifier specifications all use the watt as the base unit.

• Light-bulb and appliance ratings
• Scientific and engineering power specs
• Radio and electronics power

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