Refrigeration Tons to kW Converter
One refrigeration ton (RT) equals 3.51685 kW. This unit traces its origin to the 19th-century ice trade, where cooling capacity was measured by how much ice a system could produce....
Formula
Source: Engineering Toolbox, ASHRAE Handbook | Last reviewed: June 7, 2026
Examples
1 RT
= 3.517 kW
1 RT = 3.517 kW
50 RT
= 175.8 kW
Typical medium chiller
500 RT
= 1758 kW
Large central chiller plant
Quick Reference Table
| RT | kW |
|---|---|
| 1 | 3.52 |
| 5 | 17.58 |
| 10 | 35.17 |
| 50 | 175.84 |
| 100 | 351.69 |
| 500 | 1758.4 |
Where is this used?
During conceptual design, mechanical engineers convert building cooling loads — calculated by load software in BTU/hr or tons — to kW to establish preliminary electrical service sizing and coordinate with the electrical discipline.
A 2,000-ton central plant translates to approximately 7,034 kW of cooling capacity, requiring roughly 1,400 kW of electrical demand at a conservative COP of 5.0, which directly determines transformer sizing, switchgear ratings, and standby generator capacity.
In equipment specification and procurement, consulting engineers evaluating chiller bids must normalize disparate nameplate data: a US manufacturer quoting 500 RT, a European manufacturer quoting 1,760 kW cooling, and a Japanese manufacturer quoting 6,000,000 kcal/h all describe approximately the same machine.
Converting to a common basis — typically kW — enables meaningful comparison of efficiency metrics like kW/ton, COP, and IPLV/NPLV across all bidders.
For energy modeling and code compliance, ASHRAE 90.1 and the International Energy Conservation Code (IECC) prescribe minimum chiller efficiencies in both kW/ton (I-P) and COP (SI).
A chiller with a full-load rating of 0.56 kW/ton corresponds to a COP of 6.28 (since COP = 3.51685 / kW/ton), and energy models must convert correctly between these metrics to demonstrate code compliance.
In commissioning and ongoing operations, building automation systems often trend chiller thermal output in tons and electrical input in kW simultaneously.
Converting both to a common unit lets operators track real-time kW/ton efficiency and detect degradation — a chiller that drifts from 0.6 to 0.75 kW/ton represents a 25% increase in energy consumption for the same cooling output, flagging the need for tube cleaning, refrigerant charge correction, or compressor maintenance.
For district cooling utilities, where capacity is sold to customers in ton-hours, revenue-grade metering converts thermal measurements (flow and delta-T) into ton-hours and subsequently bills customers.
Converting ton-hours to kWh-thermal allows direct comparison against the electrical kWh consumed to produce that cooling, yielding the system-level coefficient of performance that drives plant optimization and carbon accounting.
Real-World Usage Scenarios
Central chiller plant procurement across continents
A multinational project in Singapore receives chiller bids from US manufacturers quoting 500 RT water-cooled centrifugal chillers and from Japanese and European suppliers quoting in kW. The consulting engineer converts all bids to a common unit (kW) for normalized kW/ton efficiency comparison. At 500 RT × 3.51685 = 1,758 kW per chiller, the team evaluates full-load and part-load kW/ton (or COP) across vendors, accounting for local condenser water temperatures of 86°F entering versus AHRI standard 85°F, and selects the optimal configuration based on life-cycle cost analysis rather than nameplate tonnage alone.
Data center cooling capacity verification
A colocation data center is designed with a projected IT load of 800 kW. The mechanical engineer must specify cooling capacity in tons: 800 kW / 3.51685 ≈ 227 RT. With N+1 redundancy, the final design calls for 5 × 75-ton CRAC units (375 RT installed). During commissioning, thermal load bank testing confirms that at actual supply air conditions, each unit delivers only 68 tons due to higher return air temperatures. The engineer converts actual delivered tons back to kW to verify that the 340 RT (1,196 kW) of real capacity still exceeds the 800 kW IT load with required redundancy margins.
Process cooling retrofit in pharmaceutical manufacturing
A pharmaceutical plant replaces an aging 200-ton reciprocating chiller with a new magnetic-bearing centrifugal chiller. The old chiller operated at 0.9 kW/ton (180 kW electrical draw for 200 RT), while the new chiller is rated at 0.5 kW/ton at full load. The facility engineer calculates annual energy savings: (0.9 - 0.5) kW/ton × 200 RT × 8,760 hours × 70% load factor × $0.12/kWh = $58,000/year. Converting tons to kW consistently across both old and new equipment enables accurate savings projections that justify the capital expenditure to management.
Common Mistakes to Avoid
Using metric tonne instead of short ton
The standard refrigeration ton in US practice is based on the short ton (2,000 lb), yielding 1 RT = 12,000 BTU/hr = 3.51685 kW. Some European and Asian references use the metric tonne of refrigeration (1 TR = 3.875 kW ≈ 13,220 BTU/hr). Mixing these definitions produces a 10% error in capacity calculations. Always verify which ton definition the equipment manufacturer uses — most global chiller manufacturers have standardized on the US short ton.
Ignoring operating conditions in chiller ratings
Chiller capacity in tons is rated at specific entering/leaving water temperatures per AHRI 550/590 standard rating conditions (typically 44°F leaving chilled water, 85°F entering condenser water). When operating conditions deviate — for example, 40°F chilled water supply for process cooling — actual capacity drops significantly. Converting the nameplate tonnage to kW without accounting for the operating condition derate leads to undersized equipment. Always request the manufacturer's selection software output showing capacity at actual design conditions.
Applying tons of refrigeration to heat pumps incorrectly
Heat pump heating capacity in tons of refrigeration sometimes causes confusion: a 5-ton heat pump provides 60,000 BTU/hr (17.6 kW) of cooling, but its heating output depends on outdoor air temperature. At 47°F outdoor, it may deliver near rated capacity, but at 17°F, output can drop 30-40%. When converting heat pump tons to kW for electrical load calculations, use the compressor rated load amps (RLA) and voltage rather than the nominal tonnage, because power draw varies with operating conditions and does not equal capacity divided by COP at all conditions.
Industry Standards Referenced
Frequently Asked Questions
Why is it called a ton of refrigeration?
It comes from the ice trade era. One ton of refrigeration is the rate of heat extraction required to freeze 1 ton of water at 32°F into ice at 32°F in 24 hours.
How do I convert kW back to RT?
Divide kW by 3.51685. For quick estimates, multiply kW by 0.284 to get RT.
Is this the same as a metric ton?
No. The refrigeration ton is based on the US short ton (2000 lb). A metric ton (tonne) of refrigeration is slightly different: 1 tonne = 3.875 kW ≈ 13,220 BTU/hr.
How do I convert RT to electrical kW input?
Cooling tons represent thermal capacity (heat removed), not electrical power consumed. To find electrical kW input, divide the cooling kW by the chiller's coefficient of performance (COP): kW_electrical = (RT × 3.51685) / COP. For example, a 100 RT chiller at COP 5.0 draws (351.7 / 5.0) = 70.3 kW electrical. Typical water-cooled centrifugal chillers achieve COP of 5.0-7.0, while air-cooled scroll chillers operate at COP of 2.8-3.5.
What is IPLV and how does it relate to RT and kW?
Integrated Part Load Value (IPLV) is a weighted efficiency metric defined by AHRI 550/590 that accounts for chiller performance across four load conditions (100%, 75%, 50%, 25%) with corresponding condenser water temperature relief. IPLV is expressed in kW/ton or EER. When evaluating a chiller bid, convert the IPLV kW/ton to kW at each load point: for a 500 RT chiller, 75% load = 375 RT = 1,319 kW cooling. If the chiller's part-load efficiency at that point is 0.45 kW/ton, the electrical draw is 375 × 0.45 = 168.8 kW. Summing weighted electrical draws across all four points yields the IPLV-based annual energy estimate.
Reviewed for accuracy
Reviewed against AHRI 550/590 and ASHRAE 15 standards · Last reviewed: June 7, 2026
All calculations are for reference only. Always verify with manufacturer data and a qualified engineer for critical applications. Learn about our editorial process.