BTU/hr to kW Converter
1 BTU per hour equals 0.000293071 kW. A British Thermal Unit (BTU) is defined as the amount of heat required to raise the temperature of one pound of liquid water by one degree...
Formula
Source: Engineering Toolbox, ASHRAE Handbook | Last reviewed: June 7, 2026
Examples
1000 BTU/hr
= 0.2931 kW
1 kBTU/hr
12000 BTU/hr
= 3.517 kW
1 refrigeration ton
100000 BTU/hr
= 29.31 kW
100 kBTU/hr
Quick Reference Table
| BTU/hr | kW |
|---|---|
| 1000 | 0.293 |
| 5000 | 1.465 |
| 10000 | 2.931 |
| 50000 | 14.65 |
| 100000 | 29.31 |
Where is this used?
In HVAC design, engineers cross-reference US chiller and boiler nameplate ratings — typically expressed in MBH (thousands of BTU/hr) or tons — against electrical specifications in kW to size switchgear, transformers, and emergency generator capacity.
A 300-ton chiller at 12,000 BTU/hr per ton equals 3,600,000 BTU/hr or 1,055 kW of cooling, which directly informs electrical service requirements.
In building energy modeling, conversion between BTU/hr and kW is essential for energy use intensity (EUI) calculations: ASHRAE 90.1 compliance requires annual energy consumption expressed in kBtu/ft²/yr, while utility rate structures and submeter data are typically in kWh.
Converting between these units enables accurate energy benchmarking and identifies optimization opportunities across building systems.
Process heating applications in manufacturing — including ovens, furnaces, kilns, and heat exchangers — span both unit systems depending on equipment origin: a US-built process heater rated at 2,000,000 BTU/hr must be compared against a German electric heater quoted at 586 kW to evaluate capital and operating costs on a common basis.
In data center cooling design, where heat rejection from IT equipment is measured in kW but cooling equipment is often sized in tons or BTU/hr, this conversion ensures the mechanical system matches the electrical load — typically at a ratio of 1 ton (12,000 BTU/hr or 3.517 kW) of cooling per 3-5 kW of IT load depending on cooling architecture.
For cogeneration and district energy systems, where waste heat from gas turbines (rated in BTU/hr) supplements boiler capacity (rated in both BTU/hr and kW), conversion accuracy underpins the entire thermal balance.
Finally, international equipment procurement increasingly demands fluency in both unit systems: a facilities engineer in Dubai evaluating bids from US, European, and Chinese chiller manufacturers must normalize all proposals to a common unit — typically kW — to perform meaningful technical and commercial comparisons.
Real-World Usage Scenarios
International chiller specification comparison
A US-manufactured 250-ton chiller with a nameplate rating of 3,000 MBH needs to be compared against a European competitor's bid in kW. The facilities engineer converts 3,000,000 BTU/hr to 879.2 kW to evaluate cooling efficiency (kW/ton), electrical service requirements, and total cost of ownership against bids from German and Italian manufacturers who quote exclusively in kW. This conversion bridges procurement across different equipment origin markets and ensures accurate life-cycle cost analysis.
Heat pump sizing for commercial retrofit
During a commercial office building retrofit, the existing gas boiler is rated at 500,000 BTU/hr input with 85% efficiency, delivering 425,000 BTU/hr net heat. The design engineer needs to specify an equivalent air-source heat pump system in kW. Converting the net heating load — 425,000 × 0.000293071 = 124.6 kW — allows proper selection of modular heat pump units, each rated in kW, ensuring the new electric system meets the building's peak heating demand without oversizing.
Process heating load reconciliation
A chemical processing plant uses a thermal oil heater rated in BTU/hr (US supplier) alongside an electric immersion heater rated in kW (European supplier). The process engineer must reconcile both heat sources to confirm they collectively meet the 1.2 million BTU/hr required for a new reactor jacket. Converting the electric heater's 200 kW to 682,400 BTU/hr confirms the combined capacity is 1,882,400 BTU/hr, providing adequate margin above the 1.2 million BTU/hr demand with allowance for jacket losses and startup transient loads.
Common Mistakes to Avoid
Confusing BTU with BTU/hr
BTU is a unit of energy (quantity of heat), while BTU/hr is a unit of power (rate of heat transfer). A 100,000 BTU/hr boiler running for 2 hours delivers 200,000 BTU of energy. When reading equipment nameplates, verify whether the rating is heating capacity (BTU/hr input or output) or stored energy content. This mistake can lead to undersizing equipment by orders of magnitude in load calculations and energy audits.
Using gross vs. net conversion factors
The standard conversion factor is 1 BTU/hr = 0.000293071 kW, which is the international table (IT) value. However, some older references use the thermochemical BTU (0.000292875 kW) or the 59°F BTU. In HVAC work, always use the IT conversion. For natural gas appliance ratings, note that input BTU/hr (gross) differs from output BTU/hr (net) by the appliance efficiency — typically 80-95% for modern equipment — and the conversion to kW should reflect the rating basis.
Ignoring altitude derating
Gas-fired equipment rated in BTU/hr at sea level produces less heat output at altitude due to lower air density. At 5,000 ft elevation, derating factors of approximately 4% per 1,000 ft above sea level apply. A 100,000 BTU/hr boiler at sea level may only deliver ~80,000 BTU/hr net at 5,000 ft. When converting to kW for electrical backup or alternative fuel comparisons, account for site elevation to avoid undersizing during design.
Industry Standards Referenced
Frequently Asked Questions
What's the relationship between BTU/hr and refrigeration tons?
1 RT (refrigeration ton) = 12,000 BTU/hr = 3.51685 kW. RT comes from the heat needed to melt 1 ton of ice in 24 hours.
Is BTU the same as BTU/hr?
No. BTU is a unit of energy (quantity of heat). BTU/hr is a unit of power (rate of heat transfer). A 10,000 BTU/hr heater running for 3 hours delivers 30,000 BTU of energy.
How do I convert kW to BTU/hr?
Multiply kW by 3412.14. So 5 kW = 17,060.7 BTU/hr. For refrigeration tons, multiply kW by 0.2843 to get RT.
Why do US HVAC specs use BTU/hr while the rest of the world uses kW?
The US HVAC industry developed around British imperial units and has maintained them due to legacy standards, existing infrastructure documentation, and practitioner familiarity. ASHRAE, though a global organization, publishes its fundamentals in I-P (inch-pound) and SI parallel editions. The BTU/hr remains dominant in North American equipment catalogs, building codes, and energy codes like ASHRAE 90.1, though the trend toward international harmonization is gradually increasing kW usage.
How does altitude affect BTU/hr to kW conversion?
The mathematical conversion factor (0.000293071) does not change with altitude — it is a fixed unit relationship. However, gas-fired equipment delivers less heat output at altitude due to reduced air density affecting combustion. A 100,000 BTU/hr input-rated boiler at sea level may only deliver ~80,000 BTU/hr net output at 5,000 ft after derating. When converting equipment ratings for high-altitude installations, ensure you are converting the derated output rating, not the sea-level nameplate value.
Reviewed for accuracy
Reviewed against ASHRAE 90.1 and AHRI 550/590 standards · Last reviewed: June 7, 2026
All calculations are for reference only. Always verify with manufacturer data and a qualified engineer for critical applications. Learn about our editorial process.