Calculate AC consumption using tonnage, star rating, inverter type, hours and electricity tariff.
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AC Cost Audit
Understand how tonnage, star rating and runtime affect cooling cost.
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Input Details
Fill what you know. If a value is unknown, keep the practical default and verify the nameplate later.
How many units of electricity does a 1.5 ton AC use per hour?
Short answer: A 1.5 ton (18,000 BTU) AC draws about 1.2–1.8 kW while its compressor runs at full load, so it uses roughly 1.2–1.8 units (kWh) per hour; 5-star models sit at the lower end and 2–3 star models at the higher end. Inverter ACs slow the compressor once the room is cool, so their real average at 24–26 °C is often 0.8–1.2 units per hour. At 8 hours a day that is about 190–430 kWh a month, or roughly ₹1,500–3,400 at ₹8/kWh in India, or about $34.33–77.82 at the US average of 18.3¢/kWh.
AC power consumption per hour (check the BEE label for your model)
AC size
Full-load kWh/hour
Inverter average kWh/hour
Monthly kWh at 8 h/day
1 ton (12,000 BTU)
0.9–1.2
0.6–0.9
145–290
1.5 ton (18,000 BTU)
1.2–1.8
0.8–1.2
190–430
2 ton (24,000 BTU)
1.7–2.4
1.1–1.6
265–575
Tip: Each 1 °C higher set-point saves roughly 5–6% of AC energy; 24–26 °C is the efficient range.
Using this calculator outside India? Outside India? Pick your currency at the top of the page and enter the per-kWh rate printed on your bill. Typical residential averages: USA 18.3¢/kWh (EIA, July 2026; California 33.6¢, Texas 15.9¢), UK about £0.25/kWh, Germany about €0.38/kWh, UAE about AED 0.23–0.38/kWh, Canada about C$0.13–0.20/kWh and Australia about A$0.30–0.35/kWh. The kWh result is the same in every country; only the cost changes.
By Harshad Kumar Sharma · Last reviewed · Method: kWh = watts × hours × days ÷ 1,000
AC estimated watts are adjusted by tonnage, inverter/non-inverter type and star rating. Actual compressor cycling depends on room heat load, outdoor temperature and set temperature.
This is a preliminary planning estimate. For certified audits, use site measurement and nameplate readings.
FAQ
Does an inverter AC really save electricity?
Yes, typically 25–40% compared with a non-inverter AC of the same size when it runs for long hours, because the compressor slows down instead of switching fully on and off.
What temperature should I set my AC to save electricity?
24–26 °C. Each degree higher saves about 5–6% of cooling energy, and using a ceiling fan together with the AC lets you set a higher temperature comfortably.
Why is AC estimate not exact?
AC compressor cycles. Room size, insulation, temperature and maintenance change actual consumption.
Should I buy inverter AC?
Only if usage is high enough. The page shows saving but payback depends on purchase price difference.
Before replacing an AC
Check filter cleaning, thermostat setting, room insulation and runtime first. Replacement should be decided with ROI, not only star rating.
Accuracy note
The result is a planning estimate. Use nameplate wattage, measured runtime and current tariff for professional-level accuracy.