BTU/hr to Tons of Refrigeration Converter
This calculator converts between BTU per hour (BTU/hr), tons of refrigeration, and kilowatts (kW), the three units used to describe the cooling capacity of air conditioners, heat pumps and HVAC equipment. It matters because New Zealand rates cooling capacity in kilowatts, while imported units and older engineering documents often use BTU/hr or tons, so comparing products means switching between all three. You choose which unit you are converting from, enter a value, or pick a common air conditioner size from the preset list, ranging from a small 6,000 BTU/hr room unit up to a 60,000 BTU/hr commercial system, and the calculator instantly returns the equivalent tons of refrigeration, BTU per hour and kilowatts, backed by a conversion breakdown, a worked example and a reference table of typical BTU, tons and kW figures against likely room uses. The maths is fixed: 1 ton of refrigeration equals exactly 12,000 BTU/hr, and 1 kW equals 3,412.142 BTU/hr, so results are precise rather than estimated. Use it to translate a heat pump's kW rating into tons or BTU/hr for comparison shopping, to check a manufacturer's spec sheet against a NZ-rated system, or to understand the numbers on an air conditioner's nameplate. Because it converts units rather than sizing a room, still get a heat load assessment from a qualified installer before buying, since insulation, glazing and orientation affect the capacity you need.
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Quick Reference
Key conversion factors used by this calculator:
Common BTU to Tons Conversion Table
| BTU/hr | Tons of Refrigeration | Kilowatts (kW) | Typical Use |
|---|
Your Conversion Breakdown
Worked Example
How to Convert BTU/hr to Tons of Refrigeration
The ton of refrigeration (TR) is a unit of cooling capacity widely used in the HVAC and refrigeration industries, particularly in the United States and parts of Asia. In New Zealand and Australia, air conditioning capacity is most commonly rated in kilowatts (kW), but you will still encounter BTU/hr and tons on imported units, product specifications, and engineering documents.
The conversion formula is straightforward:
- Tons to BTU/hr: multiply tons by 12,000
- BTU/hr to tons: divide BTU/hr by 12,000
- BTU/hr to kW: divide BTU/hr by 3,412.142
- kW to BTU/hr: multiply kW by 3,412.142
- Tons to kW: multiply tons by 3.516853
- kW to tons: divide kW by 3.516853
Where Does the "Ton" Unit Come From?
The ton of refrigeration has an unusual origin. It refers to the cooling effect produced by melting one short ton (2,000 lb or approximately 907 kg) of ice over a 24-hour period. The latent heat of fusion of ice is 144 BTU per pound, so melting 2,000 lb of ice in 24 hours requires 2,000 x 144 = 288,000 BTU per day, which equals exactly 12,000 BTU per hour. This historical definition has stuck as the industry standard, even though modern refrigeration equipment uses electricity rather than ice.
Conversion Reference Table
| BTU/hr | Tons (TR) | kW | Typical application |
|---|---|---|---|
| 6,000 | 0.50 | 1.76 | Small study or bedroom |
| 9,000 | 0.75 | 2.64 | Standard bedroom (up to 15 m2) |
| 12,000 | 1.00 | 3.52 | Bedroom or small living room |
| 18,000 | 1.50 | 5.28 | Large bedroom or medium lounge |
| 24,000 | 2.00 | 7.03 | Open-plan living area (30 to 40 m2) |
| 36,000 | 3.00 | 10.55 | Large open plan or small office |
| 48,000 | 4.00 | 14.07 | Commercial retail or medium office |
| 60,000 | 5.00 | 17.58 | Large commercial space |
BTU/hr vs kW for NZ Heat Pumps
In New Zealand, heat pump and air conditioning capacity is marketed in kilowatts. A typical single-room heat pump for a New Zealand bedroom might be rated at 2.5 kW to 3.5 kW (approximately 8,530 to 11,942 BTU/hr, or 0.71 to 1.00 tons). A whole-home multi-split system may be 7 to 14 kW total (23,885 to 47,770 BTU/hr, or 1.99 to 3.98 tons). When comparing NZ products against US-market units or technical specifications, this converter lets you check equivalent capacity directly.
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Sources and method: Conversion constants from ASHRAE Handbook of Fundamentals and NIST special publication 811 (Guide for the Use of the International System of Units). 1 ton of refrigeration = 12,000 BTU/hr (exact, by definition). 1 kWh = 3,412.142 BTU (based on 1 BTU = 1,055.05585 J and 1 kWh = 3,600,000 J).
This converter provides the standard engineering conversion between BTU/hr, tons of refrigeration, and kilowatts. For HVAC system sizing, consult a qualified engineer or installer who can perform a proper heat load calculation based on your specific space, climate zone, insulation, and occupancy.