How many BTU/hr is 1 ton of refrigeration?

One ton of refrigeration equals exactly 12,000 BTU per hour (BTU/hr). This unit originates from the amount of heat required to melt one short ton (2,000 pounds) of ice in 24 hours, which works out to 12,000 BTU/hr. So a 2-ton air conditioner has a cooling capacity of 24,000 BTU/hr, and a 5-ton unit delivers 60,000 BTU/hr.

How do I convert BTU/hr to kilowatts?

To convert BTU per hour to kilowatts, divide by 3,412.142. For example, 12,000 BTU/hr divided by 3,412.142 equals approximately 3.517 kW. To go the other way, multiply kilowatts by 3,412.142 to get BTU/hr. This conversion is based on the equivalence 1 kWh = 3,412.142 BTU.

What size air conditioner do I need for my room?

As a rough guide, you need approximately 150 to 200 BTU/hr per square metre of floor area in a standard NZ home. A 20 m2 bedroom typically requires around 3,000 to 4,000 BTU/hr (0.25 to 0.33 tons). A 40 m2 open-plan living area might need 6,000 to 9,000 BTU/hr (0.5 to 0.75 tons). Factors such as ceiling height, insulation, sun exposure, and the number of occupants all affect the required capacity. It is advisable to get a professional heat load assessment for larger installations.

BTU/hr to Tons of Refrigeration Converter

Convert between BTU per hour (BTU/hr), tons of refrigeration, and kilowatts (kW). Used for sizing air conditioners, heat pumps, and HVAC systems. Enter any value and the other two update instantly.

1 ton of refrigeration = 12,000 BTU/hr = 3.517 kW.

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Standard conversion Based on the international definition: 1 ton of refrigeration = 12,000 BTU/hr = 3.516853 kW.

Enter a Value to Convert

Convert from

BTU per hour (BTU/hr)

BTU/hr

Tons of refrigeration (TR)

tons

Kilowatts (kW)

Common air conditioner presets

Quick Reference

Key conversion factors used by this calculator:

1 ton of refrigeration= 12,000 BTU/hr

1 ton of refrigeration= 3.517 kW

1 kW= 3,412.142 BTU/hr

1 BTU/hr= 0.0000833 tons

1 BTU/hr= 0.000293 kW

Conversion Results

Tons of Refrigeration
2.00
TR

BTU per Hour

24,000

BTU/hr

Kilowatts

7.034

Common BTU to Tons Conversion Table

BTU/hr	Tons of Refrigeration	Kilowatts (kW)	Typical Use

Your Conversion Breakdown

Input value-

Conversion factor (to tons)1 ton = 12,000 BTU/hr

Conversion factor (to kW)1 kW = 3,412.142 BTU/hr

Tons of refrigeration-

Kilowatts-

Worked Example

Input24,000 BTU/hr

Tons = BTU/hr / 12,00024,000 / 12,000

Result (tons)2.00 tons

kW = BTU/hr / 3,412.14224,000 / 3,412.142

Result (kW)7.034 kW

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.

Note: BTU/hr refers to cooling capacity in this context. This is different from BTU used to describe the heat content of fuels such as natural gas (which are measured in BTU per unit volume or weight, not per hour). HVAC BTU ratings are always a rate (per hour).

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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.