# AC Annual Running Cost Calculator

> Estimate an air conditioner’s yearly electricity use and cost from its power draw, or from cooling capacity and EER, plus hours, days and tariff.

Category: Energy & environment · Applies to: Worldwide · Last updated: 2026-10-29
Interactive calculator: https://calculators.geekmidst.com/calculators/ac-annual-running-cost-calculator

An air conditioner’s electrical input is its cooling capacity divided by its efficiency ratio (EER). Multiply by the hours it runs and the share of time the compressor works hard to get yearly kWh.

Also called: Air conditioner running cost calculator, AC electricity cost calculator.

## Inputs
- I know the (options: Capacity and EER, Input power; default capacity)
- Input power (unit W; default 1000)
- Cooling capacity (default 3.5)
- Capacity unit (options: kW, BTU/h; default kw)
- Efficiency ratio (EER) (default 3.5)
- EER unit (options: W/W, BTU/h per W; default ww)
- Hours used per day (unit h; default 8)
- Days used per year (unit days; default 120)
- Average load (unit %; default 70)
- Electricity price per kWh (default 0.25)
- Currency

## Results
- Running cost per year
- Electricity per year
- Full-load input power
- Average cost per hour of use
- Average per month

## Formula

```
Input kW = Cooling capacity (kW) ÷ EER (W/W);  kWh per year = Input kW × Load% × Hours × Days;  Cost = kWh × Price  (1 kW = 3,412.142 BTU/h)
```

Where:
- EER: cooling output divided by electrical input (W/W); a rating in BTU/h per W is divided by 3.412142
- Load%: average share of full input power while switched on

## Worked example
1. Input power: 3.5 kW ÷ 3.5 = 1 kW.
2. Energy: 1 kW × 70% × 8 h × 120 days = 672 kWh.
3. Cost: 672 × 0.25 = 168 a year.

**Result:** A 3.5 kW air conditioner with an EER of 3.5, used 8 hours a day for 120 days, costs about 168 a year at 0.25 per kWh.

## What the result means

The load figure matters most: an inverter unit in a well-insulated room may average well under its rated input. For a better estimate, measure a typical day with a plug-in or smart meter and use that average with 100% load.

## Assumptions and limits
- Efficiency and load are constant over the season.
- The tariff is a flat rate per kWh.
- Real consumption depends on outdoor temperature, insulation, thermostat setting and the unit’s part-load behaviour.

## Questions

### What is 1 ton of cooling in kW?

One refrigeration ton is 12,000 BTU/h, about 3.517 kW of cooling. Choose BTU/h and enter 12,000 per ton.

### EER or SEER?

EER is measured at one test condition; seasonal ratios (SEER, ISEER) average over a typical season and usually give a more realistic yearly figure.

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Source: GM¹X CalcVerse — https://calculators.geekmidst.com/calculators/ac-annual-running-cost-calculator