Free AC energy tool
AC Running Cost Calculator
Estimate your AC's power consumption in units and its daily, monthly and yearly electricity cost, with an adjustable compressor load factor and optional model comparison.
Smart result
Your AC estimate will appear here
Rated wattage is adjusted by the editable load factor before energy and cost are calculated.
Quick answer
This calculator estimates your AC's power consumption in units (kWh) and what it adds to your monthly electricity bill. Enter the AC's rated power in watts, the hours it runs and your rate per unit. Because the compressor slows down or switches off once the room is cool, an editable load factor turns rated watts into realistic average use.
Why rated wattage is not continuous consumption
An AC compressor cycles or modulates after the room approaches its set temperature. The calculator applies an editable load factor to rated input power instead of assuming full power throughout every operating hour.
Inverter and fixed-speed AC behaviour
Inverter ACs can vary compressor speed, while fixed-speed units generally cycle on and off. Actual consumption for either type depends on room size, insulation, outdoor conditions, thermostat setting, efficiency, maintenance, and usage.
Formula and transparency
Energy (kWh) = watts × quantity × hours × load factor ÷ 1,000. Cost is energy multiplied by your electricity rate. Generic values are estimates; calculation uses the wattage entered by you.
Reference: Generic household ranges and user-entered product data.
Last updated: 19 September 2026.
Real-world example
A 1.5-ton inverter split AC rated at 1,500 W runs 8 hours a day for 30 days, at an illustrative ₹8 per unit, with the compressor working at 65% of rated power on average.
- Rated power
- 1,500 W
- Daily use
- 8 hours
- Load factor
- 65%
- Rate
- ₹8/unit
Your AC may use about 234 units a month, costing about ₹1,872.
That is about 7.8 units (₹62) a day and ₹22,464 a year if used like this all year.
These are the calculator's starting values, not a measurement of any model. Use the input power on your AC's label and your own bill rate.
Assumptions
- Rated input power is reduced by the load factor you choose; the AC is not assumed to run at full power every hour.
- The electricity rate is one flat price per unit, not your state's slab structure.
- Star rating and AC type describe the unit; the wattage and load factor drive the calculation.
What can change the result?
- Hours of use
- Running 12 hours instead of 8 raises units and cost by half.
- Thermostat setting
- A lower set temperature keeps the compressor working harder and longer.
- Room and weather
- Sunlight, insulation, room size and outdoor heat change the real load factor.
- AC efficiency
- A more efficient model can draw fewer watts for the same cooling; compare models with the comparison option.
- Your tariff
- If AC use pushes you into a higher slab, each extra unit can cost more than your average rate.
What should I do next?
Frequently asked questions
How many units does a 1.5-ton AC use?+
There is no single figure. It depends on rated input power, compressor load, daily hours, weather, room conditions, thermostat setting, and AC efficiency.
Does inverter AC always save electricity?+
Not always. Inverter control can reduce cycling losses, but savings depend on sizing, usage pattern, operating conditions, and the models being compared.
Does star rating affect running cost?+
A higher-rated model is generally more efficient within its rating cohort, but compare the current energy label and rated or annual consumption for the actual models.
Why does AC consumption change with temperature?+
The temperature difference, humidity, sunlight, insulation, room occupancy, and thermostat setting change how hard and how long the compressor runs.
Is this calculator exact?+
No. It is an estimate from your wattage, runtime, load factor, and electricity rate. A plug-in energy meter or utility sub-meter provides a better measurement.