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Understanding HVAC and refrigeration capacity units is essential when selecting, specifying, sizing, or comparing air-conditioning and refrigeration equipment. Cooling equipment may be rated in BTU/h, horsepower (HP), tons of refrigeration (TR), or kilowatts (kW) depending on the manufacturer, application, and country.
At Akpo Oyegwa Refrigeration Company, we work with different types of air-conditioning, refrigeration, cold-room, and cooling systems where accurate understanding of cooling capacity is important for equipment selection and system design.
This guide explains how to convert BTU to HP, BTU to tons, BTU to kW, and other commonly used HVAC and refrigeration capacity units.
AKPO OYEGWA REFRIGERATION CO. (A.O.R.C)
BTU means British Thermal Unit. It is a unit of energy traditionally used to describe the amount of heat required to raise the temperature of one pound of water by approximately 1°F.
In HVAC and refrigeration, capacity is commonly expressed as BTU per hour (BTU/h or BTU/hr).
For example:
A higher BTU/h rating generally represents a greater rate of heat removal, assuming the ratings are being compared on the same basis.
BTU is a unit of energy, while BTU/h is a rate of heat transfer.
When discussing the cooling capacity of an air conditioner, chiller, refrigeration system, cold room or freezer, the more appropriate term is usually BTU/h.
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Kilowatt (kW) is an SI unit commonly used for power and is widely used in electrical and engineering applications.
For cooling capacity:
1 kW of cooling capacity ≈ 3,412 BTU/h
Therefore:
kW = BTU/h ÷ 3,412
9,000 BTU/h to kW:
9,000 ÷ 3,412 ≈ 2.64 kW
12,000 BTU/h to kW:
12,000 ÷ 3,412 ≈ 3.52 kW
18,000 BTU/h to kW:
18,000 ÷ 3,412 ≈ 5.28 kW
24,000 BTU/h to kW:
24,000 ÷ 3,412 ≈ 7.03 kW
36,000 BTU/h to kW:
36,000 ÷ 3,412 ≈ 10.55 kW
Cooling Capacity (kW) = BTU/h ÷ 3,412
Conversely:
BTU/h = kW × 3,412
A ton of refrigeration (TR) is a traditional unit used to describe refrigeration and air-conditioning capacity.
One ton of refrigeration is defined as:
1 TR = 12,000 BTU/h
Therefore:
TR = BTU/h ÷ 12,000
| Cooling Capacity | Approx. Refrigeration Capacity |
|---|---|
| 12,000 BTU/h | 1 TR |
| 24,000 BTU/h | 2 TR |
| 36,000 BTU/h | 3 TR |
| 48,000 BTU/h | 4 TR |
| 60,000 BTU/h | 5 TR |
| 120,000 BTU/h | 10 TR |
For example, a refrigeration system rated at 60,000 BTU/h has a nominal capacity of:
60,000 ÷ 12,000 = 5 TR
A ton of refrigeration is not a measurement of the physical weight of the refrigeration equipment.
It is a unit of cooling capacity.
Horsepower (HP) is frequently associated with refrigeration compressors, motors, pumps, fans, and other mechanical equipment.
However, BTU/h and HP do not represent the same physical quantity.
BTU/h describes a rate of heat removal, while HP describes mechanical power.
Consequently, there is no single universal BTU/h-to-HP conversion that accurately determines the horsepower of a refrigeration compressor.
A commonly used theoretical energy relationship is:
1 mechanical HP ≈ 2,545 BTU/h
Therefore, a simple theoretical conversion can be written as:
HP ≈ BTU/h ÷ 2,545
However, this should not be used as a direct method for selecting a refrigeration compressor.
A refrigeration compressor’s required horsepower depends on several factors, including:
For example, two compressors with the same nominal horsepower can have substantially different refrigeration capacities under different operating conditions.
Therefore, when selecting a compressor, the correct approach is to use the manufacturer’s compressor performance data at the required evaporating and condensing conditions.
The refrigeration system must have sufficient capacity to remove the calculated heat load while maintaining the required temperature.
Because:
1 TR = 12,000 BTU/h
and:
1 kW ≈ 3,412 BTU/h
then:
1 TR ≈ 3.517 kW
Therefore:
kW = TR × 3.517
and:
TR = kW ÷ 3.517
| Tons (TR) | BTU/h | Cooling Capacity |
|---|---|---|
| 1 TR | 12,000 BTU/h | 3.52 kW |
| 2 TR | 24,000 BTU/h | 7.03 kW |
| 3 TR | 36,000 BTU/h | 10.55 kW |
| 5 TR | 60,000 BTU/h | 17.58 kW |
| 10 TR | 120,000 BTU/h | 35.17 kW |
| 20 TR | 240,000 BTU/h | 70.34 kW |
| 50 TR | 600,000 BTU/h | 175.85 kW |
| 100 TR | 1,200,000 BTU/h | 351.69 kW |
To convert cooling capacity from kW to BTU/h:
BTU/h = kW × 3,412
Examples:
5 × 3,412 = 17,060 BTU/h
10 × 3,412 = 34,120 BTU/h
20 × 3,412 = 68,240 BTU/h
50 × 3,412 = 170,600 BTU/h
The conversion is:
TR = kW ÷ 3.517
For example:
10 kW ÷ 3.517 ≈ 2.84 TR
Therefore, a cooling capacity of 10 kW is approximately 2.84 tons of refrigeration.
| BTU/h | kW | TR |
|---|---|---|
| 5,000 | 1.47 | 0.42 |
| 6,000 | 1.76 | 0.50 |
| 9,000 | 2.64 | 0.75 |
| 12,000 | 3.52 | 1.00 |
| 18,000 | 5.28 | 1.50 |
| 24,000 | 7.03 | 2.00 |
| 30,000 | 8.79 | 2.50 |
| 36,000 | 10.55 | 3.00 |
| 48,000 | 14.07 | 4.00 |
| 60,000 | 17.58 | 5.00 |
| 72,000 | 21.10 | 6.00 |
| 120,000 | 35.17 | 10.00 |
| 240,000 | 70.34 | 20.00 |
| 600,000 | 175.85 | 50.00 |
| 1,200,000 | 351.69 | 100.00 |
Values are approximate and rounded.
For quick calculations, the following formulas can be used:
kW = BTU/h ÷ 3,412
BTU/h = kW × 3,412
TR = BTU/h ÷ 12,000
BTU/h = TR × 12,000
kW = TR × 3.517
TR = kW ÷ 3.517
HP ≈ BTU/h ÷ 2,545
BTU/h ≈ HP × 2,545
This distinction is particularly important when designing solar-powered refrigeration systems, generators, batteries and electrical distribution systems.
Correct capacity conversion is important when comparing equipment from different manufacturers or countries.
A manufacturer may specify equipment capacity in:
while another manufacturer may use a different unit.
Converting the figures to a common unit allows engineers, contractors, consultants, facility managers, and end users to make a meaningful technical comparison.
Capacity conversion is particularly useful during:
Equipment selection: Comparing air conditioners, chillers, compressors and refrigeration systems.
Cold-room design: Determining whether a refrigeration system provides the required cooling capacity.
Solar system design: Estimating the electrical energy requirements associated with refrigeration and air-conditioning loads.
Equipment replacement: Comparing an existing system with a proposed replacement.
Technical quotations: Communicating equipment capacity clearly to clients and project stakeholders.
Akpo Oyegwa Refrigeration Company provides refrigeration, air-conditioning, HVAC, cold-room and related cooling-system services.
Our services include the supply, installation, maintenance, repair and technical support of refrigeration and HVAC systems for commercial, industrial and specialized applications.
We work with cooling systems including:
For a new refrigeration or air-conditioning project, simply converting BTU/h to HP, kW or tons is not sufficient to determine the complete system design. Proper equipment selection requires consideration of the actual heat load, operating temperature, ambient conditions, product characteristics, usage pattern, insulation, door openings and other engineering parameters.
1 ton of refrigeration = 12,000 BTU/h.
1 TR ≈ 3.517 kW of cooling capacity.
1 kW ≈ 3,412 BTU/h.
Using the theoretical mechanical energy conversion:
12,000 ÷ 2,545 ≈ 4.72 HP.
However, this does not mean a 12,000 BTU/h air conditioner or refrigeration system requires a 4.72 HP compressor. Compressor horsepower must be determined from the manufacturer’s performance data and operating conditions.
No. BTU/h measures the rate of heat transfer, while horsepower measures mechanical power. They can be related through energy-equivalent calculations, but they should not be treated as interchangeable HVAC equipment ratings.
No. 1 TR is approximately 12,000 BTU/h of cooling capacity, whereas horsepower is a mechanical power unit. A refrigeration compressor’s horsepower cannot be reliably determined from TR alone.
No. Compressor selection should be based on the manufacturer’s performance data at the required evaporating temperature, condensing temperature, refrigerant, superheat, subcooling and other operating conditions.
Understanding the relationship between BTU/h, kW, tons of refrigeration and horsepower makes it easier to compare HVAC and refrigeration equipment and communicate technical requirements.
The most commonly used cooling-capacity conversions are:
1 TR = 12,000 BTU/h
1 TR ≈ 3.517 kW
1 kW ≈ 3,412 BTU/h
For horsepower, the theoretical relationship is:
1 HP ≈ 2,545 BTU/h
However, the HP figure should not be used as a direct substitute for actual refrigeration compressor capacity.
For accurate HVAC and refrigeration equipment selection, cooling capacity should be determined from the application’s actual heat load and the manufacturer’s equipment performance data.
Akpo Oyegwa Refrigeration Company provides professional refrigeration and HVAC solutions for commercial, industrial and specialized applications.