Watts to BTU/hr Converter
Convert watts to BTU per hour and BTU/hr to watts instantly. Ideal for HVAC sizing, heaters, air conditioners, and power-to-heat comparisons.
Watts ⇄ BTU/hr Conversion
You can type decimals; negative values are not allowed.
Using 1 W = 3.412142 BTU/hr.
Quick Reference
Common Watts → BTU/hr
- 500 W ≈ 1,706 BTU/hr
- 1000 W ≈ 3,412 BTU/hr
- 1500 W ≈ 5,118 BTU/hr
- 2000 W ≈ 6,824 BTU/hr
Common BTU/hr → Watts
- 5,000 BTU/hr ≈ 1,465 W
- 8,000 BTU/hr ≈ 2,345 W
- 10,000 BTU/hr ≈ 2,931 W
- 12,000 BTU/hr ≈ 3,516 W
Watts to BTU/hr Conversion Table
| Watts (W) | BTU/hr |
|---|
Table uses the exact factor 1 W = 3.412142 BTU/hr and rounds to the nearest whole BTU/hr.
Watts to BTU/hr formula
Watts (W) and BTU per hour (BTU/hr) both measure power – the rate at which energy is used or transferred. Watts are the SI unit, while BTU/hr is a common imperial unit in heating and cooling.
From watts to BTU/hr
BTU/hr = W × 3.412142
From BTU/hr to watts
W = BTU/hr ÷ 3.412142
Example 1 – 1500 W space heater
You buy a 1500 W electric space heater and want to know its heating capacity in BTU/hr.
BTU/hr = 1500 × 3.412142 ≈ 5,118 BTU/hr
So a 1500 W heater delivers roughly 5,100 BTU/hr of heat.
Example 2 – 12,000 BTU/hr window AC
A typical “1 ton” window air conditioner is rated at 12,000 BTU/hr. To express this in watts:
W = 12,000 ÷ 3.412142 ≈ 3,516 W
This means the unit can move cooling power equivalent to about 3.5 kW of heat.
What are watts and BTU/hr?
- Watt (W) – 1 joule of energy per second. Standard SI unit of power.
- BTU (British Thermal Unit) – energy needed to raise 1 pound of water by 1 °F.
- BTU per hour (BTU/hr) – BTUs delivered or removed each hour (a power unit).
In HVAC and appliance specs you’ll often see:
- Heaters and electric devices rated in watts or kilowatts (kW).
- Air conditioners, heat pumps, and furnaces rated in BTU/hr or “tons” (1 ton = 12,000 BTU/hr).
Typical use cases
- HVAC sizing – comparing electric heaters (W) with AC or furnace capacity (BTU/hr).
- Data centers & electronics cooling – converting server power draw in watts to required cooling in BTU/hr.
- Off‑grid & solar – matching inverter or generator wattage to heating/cooling loads specified in BTU/hr.
Rule-of-thumb room cooling
A very rough guideline for residential cooling is about 20 BTU/hr per square foot of living space, assuming average insulation and climate. For example:
- 200 ft² room → ~4,000 BTU/hr → ~1,173 W
- 400 ft² room → ~8,000 BTU/hr → ~2,345 W
Always adjust for ceiling height, insulation, sun exposure, windows, and occupancy.
Frequently asked questions
How do you convert watts to BTU/hr?
Multiply watts by 3.412142:
BTU/hr = W × 3.412142
How do you convert BTU/hr to watts?
Divide BTU/hr by 3.412142:
W = BTU/hr ÷ 3.412142
What is 1,000 watts in BTU/hr?
1,000 W ≈ 3,412 BTU/hr.
What is 12,000 BTU in watts?
12,000 BTU/hr ≈ 3,516 W.
Why do HVAC systems use BTU/hr instead of watts?
BTU/hr is traditional in North American heating and cooling industries and ties directly to the concept of “tons” of cooling. Watts and kilowatts are more common in electrical and international specifications, so conversions are often needed.