Residential cooling capacity
12,000 BTU/hr equals about 3.517 kW of cooling capacity. A one-ton AC may draw much less than 3.517 electrical kW because it moves heat rather than creating the same amount of heat from electricity.
Power conversion
BTU/hr to kW
Convert British Thermal Units per hour (BTU/hr) to kilowatts (kW) at the fixed ratio 1 BTU/hr = 0.00029307107 kW.
1 BTU/hr0.000293 kW
BTU/hr
Accepts zero, positive values, decimals, and either a dot or comma decimal separator.
3.5169kW
How to convert BTU/hr to kW
Three steps complete the conversion:
01
Read the BTU/hr value
Take the BTU/hr rating from the spec label, manual, or product page of the HVAC or heating unit.
02
Multiply by 0.00029307107
Apply the fixed conversion factor. Dividing by 3,412.142 returns the same result.
03
Record in kilowatts
Use kW for metric comparisons, European specs, and large-system sizing.
Formula
BTU/hr to kW formula
BTU/hr → kW
P(kW) = P(BTU/hr) × 0.00029307107
kW → BTU/hr
P(BTU/hr) = P(kW) × 3412.142
Worked example
Convert a 12,000 BTU/hr one-ton air conditioner to kilowatts. European and metric spec sheets use the kW value to describe the same equipment.
Start
12,000 BTU/hr
Apply
× 0.000293
Result
≈ 3.5169 kW
Interactive
Scale explorer for BTU/hr to kW
Drag the slider or click a tier to see where your BTU/hr value lands on the equipment scale — with live kW output.
BTU per hour
12,000
BTU/hr
Kilowatts
3.5169
kW
Closest tier:1-ton AC— Residential benchmark
Visual scale
Where kW sits on the global power scale
Click any bar to make it the reference. Every other power unit shows how many of the reference value it equals.
Log scale (×10 between gridlines)
Click any bar to set as reference
Reference: 1 kW (1,000 W). In this where kw sits on the global power scale chart, the other bars show the ratio relative to that selected value.
Fundamentals
What is BTU/hr to kW?
BTU/hr to kW converts British Thermal Units per hour to kilowatts by multiplying the BTU/hr value by 0.00029307107. One BTU/hr equals 0.29307107 watts, and 1,000 watts make one kilowatt, so the two forms of the conversion are P(kW) = P(BTU/hr) × 0.00029307107 or P(kW) = P(BTU/hr) / 3412.142. The conversion lets U.S. HVAC and heating specs align with the international SI standard used by most of the world.
A BTU per hour is a rate of thermal energy in the Imperial System. A kilowatt is a rate of power in the International System of Units (SI) equal to 1,000 watts or 1,000 joules per second. Both measure power, so they convert through a single fixed ratio.
The ratio 0.00029307107 comes from the BTU definition (1,055.05585 joules) divided by 3,600 seconds per hour, then divided again by 1,000 to scale watts into kilowatts.
Most U.S. HVAC nameplates show BTU/hr, while European, Asian, and Australian specs use kW. The same physical unit appears under two different labels — the converter translates between them without loss.
Applications
When to convert BTU/hr to kW
Real-world scenarios where this conversion shows up in engineering, HVAC, and equipment specification work.
Match U.S. to European HVAC specs
Align BTU/hr nameplates with kW ratings used on European product sheets.
Heater output comparison
Compare electric heater wattage to gas-heater BTU/hr on the same kW scale.
Engineering reports
Submit building cooling loads in kW for LEED, ASHRAE, and ISO documentation.
Generator load planning
Estimate generator sizing in kW after converting building BTU/hr loads.
Efficiency calculations
Compute EER and COP by dividing cooling kW by electrical input kW.
Guidance
Tips and common pitfalls
Do not confuse kW with kWh
kW is power (rate); kWh is energy (quantity). A 3 kW heater running for 2 hours uses 6 kWh.
Thermal kW is not electrical draw
12,000 BTU/hr of cooling = 3.517 kW of heat moved, but the AC only draws about 1.0–1.2 kW of electricity at SEER 14.
Round at the end
Apply the full 0.00029307107 factor, then round to 2–3 decimal places once — not between intermediate steps.
Reference
BTU/hr to kW conversion table
| BTU per hour (BTU/hr) | Kilowatts (kW) |
|---|---|
| 100 BTU/hr | 0.029307 kW |
| 500 BTU/hr | 0.146536 kW |
| 1,000 BTU/hr | 0.293071 kW |
| 2,000 BTU/hr | 0.586142 kW |
| 5,000 BTU/hr | 1.4654 kW |
| 8,000 BTU/hr | 2.3446 kW |
| 10,000 BTU/hr | 2.9307 kW |
| 12,000 BTU/hr | 3.5169 kW |
| 15,000 BTU/hr | 4.3961 kW |
| 18,000 BTU/hr | 5.2753 kW |
| 24,000 BTU/hr | 7.0337 kW |
| 36,000 BTU/hr | 10.5506 kW |
| 48,000 BTU/hr | 14.0674 kW |
| 60,000 BTU/hr | 17.5843 kW |
| 100,000 BTU/hr | 29.3071 kW |
In practice
Industry context and practical notes
Why kW dominates outside the U.S.
SI was adopted by the General Conference on Weights and Measures in 1960 and most national HVAC standards followed within two decades. By the 1990s, every European country plus Japan, Korea, Australia, and most of Asia-Pacific mandated SI on commercial HVAC nameplates. The U.S. is the lone holdout — and even here, ASHRAE 90.1 quietly publishes parallel SI tables for every imperial calculation. Modern equipment manufacturers print both kW and BTU/hr on the same nameplate to serve global markets without producing two separate runs.
Where engineers cross the boundary daily
U.S.-based MEP firms working on multinational projects — data centers, pharmaceutical plants, embassies — translate BTU/hr load calculations to kW on every submittal. The same applies to imported equipment: a German chiller specced at 350 kW is sold to a U.S. building owner who knows it as a 99.5-ton machine. The conversion is so routine that experienced engineers do it mentally: divide BTU/hr by 3,412 for kW, divide by 12,000 for tons. The arithmetic is fixed; the cultural and procurement context is what makes the conversion necessary.
Did you know
James Prescott Joule and William Thomson (Lord Kelvin) established the energy-power equivalence that makes this a fixed-ratio conversion. The factor has not changed since the BTU was standardized in 1956.
Interpretation
How to interpret this result
A kilowatt result is equivalent thermal power, not automatically the electricity an air conditioner or heat pump draws. For resistance heating, thermal output and electrical input can be close; for refrigeration equipment, efficiency separates the two values.
A kilowatt (kW) is 1,000 watts, and a watt is one joule per second. In HVAC specifications, cooling capacity describes the rate of heat removal; electrical input is a separate rated quantity connected to capacity through EER, SEER, or coefficient of performance (COP).
Examples
Practical calculation scenarios
Commercial heating schedule
100,000 BTU/hr equals about 29.307 kW of heat output. This is useful when an imperial boiler schedule must be compared with a metric design load.
Quality check
Mistakes to avoid
- Reading thermal kW as electrical demand
- Converting BTU instead of BTU/hr
- Rounding 0.29307107 before completing a larger load calculation
Technical reference: NIST Guide to the SI conversion-factor tables. Additional terminology: ASHRAE terminology for HVAC capacity and efficiency.
Scope
Limitations and assumptions
The result is an equivalent thermal power in kilowatts. It does not calculate an air conditioner’s electrical demand, seasonal efficiency, compressor losses, or required circuit size. Confirm whether the source rating is useful capacity, fuel input, or electrical input before comparing equipment.
Questions
Frequently asked
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Calculator Methodology
Review the constants, validation, and rounding rules used for BTU/hr to kW.
BTU Conversion Formula Guide
Place BTU/hr to kW in the wider BTU/hr and watts formula context.
Trust and accuracy
Methodology and accuracy
This page converts BTU per hour to kilowatts with 1 BTU/hr = 0.00029307107 kW. That relationship follows from the international-table BTU and the SI watt; no equipment-efficiency factor is applied. The supporting constants and review policy for the kw calculation are documented on our calculator methodology page.
Last reviewed: August 7, 2026
Calculator summary
Use this calculator when a BTU/hr heating or cooling rate must be expressed in thermal kW. Keep thermal capacity separate from electrical consumption and use manufacturer efficiency data for equipment selection.