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Convert BTU/hr to Watts instantly for HVAC system sizing, heating equipment selection, and energy efficiency calculations. Use the bidirectional converter below or browse our comprehensive reference tables.
Formula: Watts = BTU/hr x 0.29307107
1 BTU/hr = 0.29307107 W | 1 W = 3.41214 BTU/hr
Reference table covering the most common BTU/hr values found in residential and commercial HVAC equipment, with real-world applications for each rating.
| BTU/hr | Watts (W) | Typical Application |
|---|---|---|
| 500 | 146.54 | Small space heater (low setting) |
| 1,000 | 293.07 | Personal portable heater |
| 3,000 | 879.21 | Small window fan heater |
| 5,000 | 1,465.36 | Small window AC unit |
| 6,000 | 1,758.43 | Bedroom window AC |
| 8,000 | 2,344.57 | Medium room AC |
| 10,000 | 2,930.71 | Large room AC |
| 12,000 | 3,516.85 | 1 Ton AC / Mini-split |
| 18,000 | 5,275.28 | 1.5 Ton AC unit |
| 24,000 | 7,033.71 | 2 Ton AC unit |
| 30,000 | 8,792.13 | 2.5 Ton AC unit |
| 36,000 | 10,550.56 | 3 Ton central AC |
| 48,000 | 14,067.41 | 4 Ton central AC |
| 60,000 | 17,584.26 | 5 Ton commercial AC |
| 100,000 | 29,307.11 | Gas furnace output |
BTU/hr (British Thermal Units per hour) is a unit of power widely used in the HVAC industry, especially in the United States and Canada. One BTU is the amount of heat required to raise the temperature of one pound of water by one degree Fahrenheit at sea level. When expressed per hour, it becomes a measure of power: the rate at which thermal energy is produced or removed by a system.
The BTU has its origins in 18th-century British engineering, when scientists needed a practical unit to describe the energy content of fuels. Despite the name "British," the BTU is now used primarily in North American HVAC, gas utility billing, and appliance rating standards.
Watt (W) is the International System of Units (SI) standard for power. Named after Scottish inventor James Watt, one Watt equals one joule per second. Watts are used globally in electrical engineering, mechanical engineering, and physics to describe the rate of energy transfer. Because the Watt is part of the metric system, it integrates seamlessly with kilowatts (kW), megawatts (MW), and other SI-derived units.
In international markets, HVAC equipment is rated in Watts or kilowatts. When engineers compare North American specifications with equipment manufactured in Europe, Asia, or elsewhere, converting BTU/hr to Watts is essential. The conversion factor of 0.29307107 bridges these two measurement traditions, allowing accurate cross-referencing of heating and cooling capacities.
To reverse the conversion (Watts to BTU/hr), divide by 0.29307107 or multiply by 3.41214. Both directions use the same underlying physical relationship.
Given: A window AC unit rated at 8,000 BTU/hr
Step 1: Write the formula: Watts = BTU/hr x 0.29307107
Step 2: Substitute: Watts = 8,000 x 0.29307107
Result: Watts = 2,344.57 W (approximately 2.34 kW of cooling output)
Given: A 3-Ton central AC unit rated at 36,000 BTU/hr
Step 1: Watts = 36,000 x 0.29307107
Step 2: Watts = 10,550.56 W
Result: 10,550.56 W = 10.55 kW of cooling capacity
Given: A gas furnace rated at 80,000 BTU/hr output
Step 1: Watts = 80,000 x 0.29307107
Step 2: Watts = 23,445.69 W
Result: 23,445.69 W = 23.45 kW of heating output
For a quick estimate, divide the BTU/hr value by 3.4. This gives you an approximation within about 0.3% of the exact answer. For example, 12,000 BTU/hr divided by 3.4 equals roughly 3,529 W, compared to the precise value of 3,516.85 W. Close enough for quick comparisons and field estimates.
Common furnace and boiler ratings converted from BTU/hr to Watts and kilowatts.
| BTU/hr | Watts | Kilowatts | Typical Use |
|---|---|---|---|
| 10,000 | 2,930.71 | 2.93 | Small room gas heater |
| 20,000 | 5,861.42 | 5.86 | Garage heater |
| 40,000 | 11,722.84 | 11.72 | Small furnace |
| 60,000 | 17,584.26 | 17.58 | Medium furnace |
| 80,000 | 23,445.69 | 23.45 | Large furnace |
| 100,000 | 29,307.11 | 29.31 | High-capacity furnace |
| 150,000 | 43,960.66 | 43.96 | Commercial heater |
| 200,000 | 58,614.21 | 58.61 | Industrial boiler (small) |
How SEER rating affects the electrical power consumption of a 1-Ton (12,000 BTU/hr) air conditioner.
| SEER | Cooling (BTU/hr) | Electrical Input (W) | Cooling Output (W) | COP |
|---|---|---|---|---|
| 10 | 12,000 | 1,200 | 3,517 | 2.93 |
| 13 | 12,000 | 923 | 3,517 | 3.81 |
| 16 | 12,000 | 750 | 3,517 | 4.69 |
| 20 | 12,000 | 600 | 3,517 | 5.86 |
| 25 | 12,000 | 480 | 3,517 | 7.33 |
Properly sizing an air conditioner or furnace requires comparing equipment rated in BTU/hr with electrical circuits measured in Watts. Undersizing leads to poor comfort; oversizing wastes energy and causes short-cycling.
Electricians and building designers need Watt values to calculate circuit breaker sizes, wire gauges, and total building electrical loads when installing HVAC equipment.
Equipment manufactured outside North America is rated in Watts or kilowatts. Converting BTU/hr to Watts allows direct comparison of domestic and imported HVAC products.
Utility bills are calculated in kilowatt-hours (kWh). Converting HVAC output from BTU/hr to kW helps estimate running costs and compare the operating expenses of different equipment options.
BTU is energy; BTU/hr is power. Watts is a power unit, so you must use BTU/hr (not plain BTU) when converting to Watts. Many equipment labels say "BTU" when they actually mean BTU/hr.
A 12,000 BTU/hr AC unit delivers 3,517 W of cooling but may only draw 900-1,200 W of electrical power. The BTU/hr rating describes cooling capacity, not electricity consumption.
A furnace rated at 80,000 BTU/hr input with 95% AFUE only delivers 76,000 BTU/hr of usable heat (22,273 W). Always use the output rating for accurate Watt conversions.
There are several BTU definitions (thermochemical, International Table, mean). For HVAC work, the International Table BTU (1 BTU/hr = 0.29307107 W) is the standard. The differences are tiny but matter in precision engineering.
In HVAC, 1 Ton = 12,000 BTU/hr = 3,516.85 W. This has nothing to do with the metric tonne (1,000 kg). The HVAC "ton" refers to the cooling equivalent of melting one US short ton of ice per day.
For commercial and industrial systems, express results in kilowatts (divide Watts by 1,000). A 60,000 BTU/hr system is easier to discuss as 17.58 kW than as 17,584 W.
Multiply the BTU/hr value by 0.29307107 to get Watts. For example, 10,000 BTU/hr multiplied by 0.29307107 equals 2,930.71 Watts.
One Ton of cooling equals 12,000 BTU/hr or approximately 3,516.85 Watts. The term originated from the amount of cooling power needed to melt one short ton (2,000 pounds) of ice in 24 hours.
The US HVAC industry has historically used the British Thermal Unit system. BTU/hr became the standard rating for air conditioning and heating equipment in North America, while most other countries use Watts or kilowatts.
A common rule of thumb is 20 BTU/hr per square foot, but this varies based on ceiling height, insulation quality, local climate, sun exposure, number of windows, and room occupancy. A professional Manual J load calculation is recommended for accurate sizing.
Yes. The conversion factor between BTU/hr and Watts is a universal physical constant. It applies equally to heating systems, cooling systems, furnaces, boilers, and any other equipment rated in BTU/hr.
BTU (British Thermal Unit) is a unit of energy, while BTU/hr (BTU per hour) is a unit of power, meaning energy transferred per unit of time. Since Watts are also a unit of power, you must use BTU/hr, not plain BTU, when converting to Watts.
Divide the Watts value by 0.29307107, or equivalently multiply by 3.41214. For example, 1,000 Watts multiplied by 3.41214 equals 3,412.14 BTU/hr.
SEER (Seasonal Energy Efficiency Ratio) is calculated by dividing the cooling output in BTU by the electrical energy input in watt-hours over a cooling season. A higher SEER means the unit produces more BTU of cooling per watt-hour of electricity consumed, indicating greater efficiency.
The thermochemical BTU/hr equals approximately 0.29307107 Watts. The International Table BTU/hr is defined as exactly 0.29307107017 Watts. For most HVAC and practical engineering purposes, 0.29307107 is sufficiently precise.
A typical 5,000 BTU/hr window AC unit consumes about 500 Watts of electrical power and delivers approximately 1,465 Watts of cooling. A 12,000 BTU/hr unit (1 Ton) delivers about 3,517 Watts of cooling and typically draws 1,000 to 1,400 Watts of electrical power depending on its SEER rating.
Disclaimer: This BTU/hr to Watts converter is provided for informational and educational purposes only. While we strive for accuracy, always verify critical engineering calculations with a qualified HVAC professional or licensed engineer. UnitTables is not responsible for any errors or decisions made based on these conversions.