Tons to kW Calculator
Convert tons of refrigeration to kW. 1 ton = 3.51685 kW. Live HVAC sizing calculator.
Common conversions
| Input | Result |
|---|---|
| 1 RT | 3.52 kW |
| 2 RT | 7.03 kW |
| 3 RT | 10.55 kW |
| 5 RT | 17.58 kW |
| 10 RT | 35.17 kW |
| 20 RT | 70.34 kW |
| 50 RT | 175.84 kW |
| 100 RT | 351.69 kW |
The math behind it
- kW = 8 × 3.51685
- kW ≈ 28.13
Everything you need to know
Tons of refrigeration describe cooling power, not weight, and converting to kW is often the fastest way to compare an HVAC quote against an engineering spec or an electrical load calculation.
What a ton of refrigeration measures
One ton of refrigeration equals exactly 12,000 BTU/hr of cooling, or 3.51685 kW. The name comes from a 19th-century reference point: the cooling effect of melting one short ton (2,000 lb) of ice in 24 hours. Modern compressors don't melt ice, but the unit survived because it was already standard on ice-based cooling equipment when mechanical refrigeration took over.
Sizing residential AC by tons
A common rule of thumb for central air conditioning is about 1 ton per 400 to 600 square feet of living space, though hotter climates, poor insulation, high ceilings, and large windows push toward the lower end of that range (more tons per square foot). A 1,800 sq ft home might need 3 to 4.5 tons (10.55 to 15.83 kW), while the same home in a mild climate with good insulation could get by on 3 tons. These figures are starting points; a licensed contractor's Manual J calculation is the accurate way to size a system.
Tons to kW for commercial systems
Commercial rooftop units, chillers, and process cooling equipment are often quoted in tons by US suppliers but need to be expressed in kW for energy modeling, electrical load calculations, or when comparing against international equipment. A 50-ton rooftop unit is about 175.84 kW of cooling, and a 200-ton chiller plant is about 703.4 kW. Getting this conversion right matters when the cooling kW feeds into a broader building energy model.
Common applications
Contractors quote in tons; energy modeling tools work in kW. Convert before plugging into Manual J or PV self-consumption tools.
European AC equipment lists kW only. Convert from US tons to find matching capacity from European suppliers.
Facility cooling capacity is often quoted in tons by contractors but modeled in kW for power budgets. Converting keeps electrical and mechanical designs aligned.
Once tons are converted to kW, you can estimate the electrical draw of the compressor via COP and size a generator or UPS large enough to keep cooling running during an outage.
Common mistakes
Refrigeration tons reference the US short ton of ice. Don't confuse with metric tonne; they're different units.
A 5-ton unit produces 17.58 kW of cooling but typically draws only 5-7 kW of electricity. Don't use the cooling kW figure for panel load calculations.
Rule-of-thumb sizing (1 ton per 400-600 sq ft) is a starting estimate, not a substitute for a proper load calculation that accounts for insulation, windows, and climate.
The rounding error is small per ton but adds up on large commercial systems; a 200-ton plant's error grows to several kW of unaccounted capacity.
Frequently asked questions
How many kW is a 5-ton AC unit?+
About 17.58 kW of cooling output, using 5 × 3.51685. Electrical input is lower, typically 5-7 kW depending on efficiency.
What size AC do I need for a 2,000 sq ft house?+
Roughly 3.5 to 5 tons (12.3 to 17.58 kW), using the rule of thumb of 1 ton per 400-600 sq ft. A Manual J load calculation gives a precise number.
Is 1 ton exactly 3.5 kW?+
Not quite. 1 ton of refrigeration is exactly 3.51685 kW. Rounding to 3.5 kW is close enough for casual estimates but introduces error on large systems.
How many kW is a 10-ton chiller?+
About 35.17 kW of cooling, using 10 × 3.51685.
Does more tons mean more electricity use?+
Yes, generally. More tons means more cooling output, which usually requires more electrical input, though a higher-efficiency (higher SEER or COP) unit can produce more tons per kW of electricity.
Why do HVAC contractors quote in tons but engineers use kW?+
US residential and light-commercial HVAC has historically used tons, while international and engineering-focused work uses kW. Converting lets you compare quotes and specs from either convention.
Is a 'ton' in refrigeration the same everywhere in the world?+
Mostly yes for the US ton of refrigeration (3.51685 kW), but always confirm; some regions define cooling capacity purely in kW and don't use tons at all.
How many kW is a 1.5-ton mini-split?+
About 5.28 kW of cooling, using 1.5 × 3.51685.
Can I convert tons to kW without a calculator?+
Yes. Multiply the tons by 3.51685, or roughly 3.5 for a quick estimate. For 5 tons, that's about 17.6 kW.