AC Ton Converter (TR to BTU, kW, Watts)
1.5 ton = 18,000 BTU/h = 5.28 kW of cooling — and about 1.5 kW of electricity at EER 3.5.
The size of the AC: tons of refrigeration (TR), BTU/h, kW, W or kcal/h. A rating in frigorías per hour (frig/h) is the same number in kcal/h.
18,000 BTU/h · 5,275 W · 4,536 kcal/h
Electricity used
The tonnage is cooling, not the power drawn. The power drawn is the cooling divided by the efficiency on the label.
About 1,507 W (1.51 kW) at full load
- 1.51 kWh for each hour at full load
- 12.1 kWh for 8 hours a day, 362 kWh in 30 days
From an Indian BEE star label
The label’s yearly units assume 1,600 hours of cooling: units ÷ 1,600 is the average power in kW.
Common AC sizes
| BTU/h | TR | kW | kcal/h |
|---|---|---|---|
| 5,000 | 0.42 | 1.47 | 1,260 |
| 6,000 | 0.5 | 1.76 | 1,512 |
| 8,000 | 0.67 | 2.34 | 2,016 |
| 9,000 | 0.75 | 2.64 | 2,268 |
| 10,000 | 0.83 | 2.93 | 2,520 |
| 12,000 | 1 | 3.52 | 3,024 |
| 15,000 | 1.25 | 4.4 | 3,780 |
| 18,000 | 1.5 | 5.28 | 4,536 |
| 24,000 | 2 | 7.03 | 6,048 |
| 30,000 | 2.5 | 8.79 | 7,560 |
| 36,000 | 3 | 10.55 | 9,072 |
| 48,000 | 4 | 14.07 | 12,096 |
| 60,000 | 5 | 17.58 | 15,120 |
About the AC Ton Converter (TR to BTU, kW, Watts)
Air-conditioner sizes are cooling capacities, quoted in tons of refrigeration (TR), BTU per hour, kilowatts or kcal/h depending on the country. One ton of refrigeration is exactly 12,000 BTU/h — about 3.517 kW — so a 1.5-ton AC removes 18,000 BTU of heat an hour (5.28 kW), and a 12,000 BTU unit is a 1-ton AC.
The ton is not what the AC draws from the socket. Its electrical input is the cooling capacity divided by its efficiency: with an EER of 3.5 W/W, a 1.5-ton AC draws about 1.5 kW at full load — 1.5 kWh of electricity for each hour it runs flat out. Enter the EER, ISEER or SEER from the label to estimate it for your AC.
How to use it
- Enter the capacity and pick its unit: tons (TR), BTU/h, kW, W or kcal/h. The other units appear at once.
- Under Electricity used, choose the rating printed on the label — EER or COP (W/W); ISEER, SEER or CSPF (W/W, seasonal); or the US EER or SEER in Btu/W·h — and enter it, to see the power the AC draws and the energy it uses per hour and per day.
- With an Indian BEE star label you can also enter the units (kWh) per year: the label assumes 1,600 hours of cooling a year.
- Copy the result or a link to it.
Examples
1.5 TR
18,000 BTU/h = 5.275 kW = 4,536 kcal/h
12,000 BTU/h
1 TR = 3.517 kW
7 kW
1.99 TR = 23,885 BTU/h
1.5 TR at EER 3.5 W/W
About 1,507 W: 1.51 kWh for each hour at full load
24,000 BTU/h at EER 12 Btu/W·h
2,000 W (24,000 ÷ 12)
3,000 kcal/h (frigorías/h)
3.489 kW = 0.99 TR
Common uses
- Comparing air conditioners labelled in tons, BTU/h and kW.
- Estimating how much electricity an AC uses per hour or per day before buying it.
- Checking a contractor’s or a datasheet’s capacity figures in another unit.
- Converting chiller and cold-room capacities between TR and kW.
The conversion factors
- 1 TR = 12,000 BTU/h exactly: originally the heat that melts a short ton (2,000 lb) of ice in 24 hours
- 1 BTU/h = 0.293071 W (1 Btu = 1,055.05585262 J)
- 1 TR = 3,516.85 W = 3.517 kW
- 1 kcal/h = 1.163 W exactly (1 kcal = 4,186.8 J)
- 1 kW = 3,412.14 BTU/h = 0.2843 TR = 859.85 kcal/h
The factors are those of NIST Special Publication 811, Appendix B, which gives the ton of refrigeration as 12,000 Btu/h = 3,516.853 W.
Cooling capacity is not the power drawn
An air conditioner pumps heat out of a room and uses less electricity than the heat it moves. The ratio is its efficiency:
- EER (energy efficiency ratio), or the COP for cooling, is the cooling capacity ÷ the electrical input at the rated test conditions, in W/W. Input power = cooling capacity ÷ EER.
- ISEER (India), SEER (Europe) and CSPF (the cooling seasonal performance factor of ISO 16358, which ISEER adapts) are seasonal ratios in W/W: the cooling over a year of typical weather divided by the electricity used, part-load running included. Dividing by them gives an average power, not the most the AC draws.
- In the US, EER and SEER (SEER2) are in Btu per watt-hour: divide by 3.412 for W/W, so a US EER of 12 is 3.52 W/W.
A 1.5-ton (5.28 kW) AC with an EER of 3.5 therefore draws about 1.51 kW at full load, and one with an ISEER of 5 uses about 1.06 kW on average over the season.
Reading an Indian BEE star label
The BEE label of a room AC shows the rated cooling capacity in watts (at 100% and at 50%), the ISEER and the electricity used in units (kWh) per year. The yearly figure assumes 1,600 hours of cooling a year, so units per year ÷ 1,600 is the average power in kW: a label showing 1,000 units a year averages 0.625 kW. BEE reviews the star bands every two years, so compare ISEER values rather than stars across years. Use the rated capacity in watts from the label for exact figures: a “1.5-ton” model need not be rated at exactly 5,275 W. The rules are in BEE’s room air conditioner labelling regulations; tests follow IS 1391.
Limitations
- Ratings are measured at standard test conditions. Real power use depends on the outdoor temperature, the thermostat setting and the room, and for an inverter AC on how hard the compressor runs.
- Seasonal ratings (ISEER, SEER, CSPF) are averages over a year of typical weather, not the most power the AC can draw.
- This converter does not size an AC for a room: use the AC tonnage calculator for that, or the HVAC BTU calculator for airflow and water flow.
- The cost of the electricity depends on your tariff: multiply the kWh by your price per unit, or use the electricity bill calculator.
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Frequently asked questions
How many kW is a 1.5-ton AC?
5.28 kW of cooling (1.5 × 3.517 kW), or 18,000 BTU/h. That is the heat it removes, not the electricity it uses: at an EER of 3.5 it draws about 1.5 kW.
How many BTU is 1 ton?
12,000 BTU per hour, exactly. So 9,000 BTU/h is 0.75 ton, 18,000 BTU/h is 1.5 ton and 24,000 BTU/h is 2 ton.
How much electricity does a 1.5-ton AC use per hour?
Divide the cooling capacity by the EER: 5.28 kW ÷ 3.5 = about 1.5 kWh for each hour at full load. An inverter AC runs below full load much of the time, so it uses less on average — which is what the seasonal rating (ISEER, SEER) shows.
What is the difference between TR and kW?
Both measure power. TR is the refrigeration trade’s unit (12,000 BTU/h); kW is the SI unit. 1 TR = 3.517 kW and 1 kW = 0.284 TR. On an AC, a figure in kW is the cooling capacity unless it says power input or power consumption.
What does EER mean?
Energy efficiency ratio: the cooling capacity divided by the electrical input at standard test conditions. In W/W, an EER of 3.5 means 3.5 kW of cooling for each kW of electricity. In US units (Btu/W·h) the same AC has an EER of about 11.9.
What are frigorías?
A frigoría is a kilocalorie of heat removed, so a rating in frigorías per hour (frig/h) is the same number in kcal/h. 3,000 frig/h is 3.49 kW, about 1 ton.