Watts to TR Conversion: Formula & Calculator

This calculator converts power in watts (W) to refrigeration tons (TR), the standard unit for cooling capacity in HVAC and refrigeration. Enter the electrical or thermal power in watts, and you get the equivalent cooling capacity in refrigeration tons, along with the reverse conversion for reference. The conversion is based on the definition that 1 refrigeration ton equals 3,516.85284 watts.

Formula

The conversion from watts to refrigeration tons is a simple division:

TR = W / 3516.85284

Where:

• TR = cooling capacity in refrigeration tons (also written as RT or ton)
• W = power in watts (W)
• 3516.85284 = the exact number of watts in one refrigeration ton

This number comes from the definition of a refrigeration ton: the rate of heat removal required to freeze one short ton (2,000 lb) of water at 32°F in 24 hours. That rate equals 12,000 BTU per hour, and 1 BTU/hr = 0.29307107 watts, so 12,000 × 0.29307107 = 3,516.85284 W.

Worked Example

Using the default input of 1,000 W:

1. Start with the formula: TR = W / 3516.85284
2. Plug in the value: TR = 1000 / 3516.85284
3. Calculate: TR = 0.2843

So 1,000 watts equals approximately 0.284 refrigeration tons. The calculator shows 0.284 TR (rounded to 3 decimal places).

Why the Conversion Matters

Refrigeration tons are used almost exclusively in North America for cooling equipment—air conditioners, chillers, heat pumps, and refrigerated storage. In most other parts of the world, cooling capacity is given in kilowatts (kW) or BTU/hr. When you compare equipment from different regions or read technical specs, you often need to switch between these units.

The conversion is also essential for sizing: if you know the electrical power draw of a compressor (in watts) but need to express its cooling output in tons, this calculation gives you the equivalent. Keep in mind that the electrical input power is not the same as the cooling output—a typical air conditioner might draw 1,000 W electrically but produce about 3,500 W (1 TR) of cooling because of the coefficient of performance (COP). The conversion here treats watts as a direct measure of heat removal, which is correct for thermal power, not electrical input.

How to Choose the Right Unit

When you see a power rating, check what it actually measures:

• Electrical watts (W or kW) – the electricity consumed by the compressor, fan, and controls. This is what your utility bill charges.
• Cooling watts (W or kW) – the heat removed from the space per unit time. This is the “capacity� of the system.
• BTU/hr – common in residential AC specs. 1 TR = 12,000 BTU/hr.
• Refrigeration tons (TR) – used for commercial and industrial equipment.

If you only have the electrical input in watts, do not use this calculator to get the cooling tons unless the device is 100% efficient (which is never the case). Instead, look for the capacity rating on the nameplate or spec sheet. This calculator is for converting a given thermal power value, not for estimating efficiency.

Common Mistakes and Misconceptions

A frequent error is mixing up the two types of watts. For example, a 1,500 W space heater produces 1,500 W of heat, so its “cooling� equivalent would be negative—it adds heat. But a 1,500 W air conditioner might have a cooling capacity of 5,000 W (about 1.4 TR) because it moves more heat than the electricity it consumes. So always confirm whether the watt value is input power or output capacity.

Another mistake is using the wrong conversion factor. Some sources round 1 TR to 3,517 W, which is fine for quick estimates, but for precise engineering work use 3,516.85284. Also, be careful with kilowatts: 1 kW = 1,000 W, so if you have 10 kW, that’s 10,000 W, not 10 W.

Practical Examples

Here are a few real-world conversions to give you a feel for the numbers:

• A small window AC with 5,000 BTU/hr cooling capacity = 5,000 / 12,000 = 0.417 TR. In watts: 0.417 × 3,516.85 ≈ 1,466 W of cooling.
• A typical 3-ton residential AC unit = 3 × 3,516.85 = 10,550 W of cooling capacity (about 10.6 kW).
• A large chiller rated at 500 TR = 500 × 3,516.85 = 1,758,426 W ≈ 1.76 MW of cooling.

These examples show that refrigeration tons are large units—one ton is roughly the cooling of a small window unit.

Limits of the Conversion

This conversion is a pure unit change; it does not account for efficiency, temperature, or pressure. It assumes you are converting a thermal power value (heat removal rate) from watts to tons. It is not valid for electrical power unless the device is a perfect heat pump with a COP of 1, which is physically impossible. Also, the definition of a “ton� is based on the short ton (2,000 lb) and the latent heat of fusion of ice (144 BTU/lb). Some countries use a “metric ton� of refrigeration, but that is rare; stick with the standard definition unless specified otherwise.

Frequently Asked Questions

How many watts are in 1 refrigeration ton?

Exactly 3,516.85284 watts. This is derived from 12,000 BTU/hr (the heat removal rate) multiplied by 0.29307107 W per BTU/hr.

Is 1 TR equal to 1 kW?

No. 1 TR is about 3.517 kW of cooling capacity. A 1 kW electrical input to an air conditioner might produce roughly 3–4 kW of cooling (COP of 3–4), so the two are different quantities.

How do I convert TR to BTU/hr?

Multiply the TR value by 12,000. For example, 2 TR = 24,000 BTU/hr. Conversely, divide BTU/hr by 12,000 to get TR.

What is the difference between a refrigeration ton and a ton of weight?

They are unrelated. A refrigeration ton is a unit of power (heat removal rate), named after the ice-melting analogy. A weight ton is a unit of mass (2,000 lb in the US short ton).

Can I use this for electrical power consumption?

Only if you are converting a thermal power value. For electrical input, you would need to know the efficiency or COP to estimate cooling capacity. This calculator does not do that.

Why do some sources say 1 TR = 3.5 kW?

That is a rounded approximation. The exact value is 3.51685284 kW, but 3.5 kW is often used for quick mental math. For precise engineering, use the exact factor.

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in t | Power | W | 1000 | 0
out tr | Refrigeration tons | TR | t / 3516.85284 | 3
out kw | Power in kilowatts | kW | t / 1000 | 2