Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Cost per day
$4.48
Cost per month
$134.40
Cost for a 120-day season
$537.60
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One click, a permanent link with your numbers baked in.
How to use this
- 1Enter ac unit wattage (W).
- 2Enter hours run per day (hrs).
- 3Enter electricity rate ($/kWh).
- 4Read your cost per day on the right — it updates as you type.
- 5Hit Share to keep the scenario or send it to someone.
About this calculator
Air conditioner running cost follows the same watt-hour math as any appliance: wattage times hours run gives energy used, converted to kilowatt-hours and multiplied by your utility rate. This calculator supports both window units and central systems by wattage input.
Worked example
Using the values the calculator loads with:
Inputs
- AC unit wattage: 3500 W
- Hours run per day: 8 hrs
- Electricity rate: 0.16 $/kWh
Results
- Cost per day: $4.48
- Cost per month: $134.40
- Cost for a 120-day season: $537.60
What each field means
Inputs
- AC unit wattage (W)
- The ac unit wattage used in the calculation, measured in W. Starts at 3500 W so you have a working example on load. Accepted range: 500–10000 W.
- Hours run per day (hrs)
- The hours run per day used in the calculation, measured in hrs. Starts at 8 hrs so you have a working example on load. Accepted range: 0–24 hrs.
- Electricity rate ($/kWh)
- The electricity rate used in the calculation, measured in $/kWh. Starts at 0.16 $/kWh so you have a working example on load. Accepted range: 0.05–0.5 $/kWh.
Results
- Cost per day
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Cost per month
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Cost for a 120-day season
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How much does it cost to run an air conditioner?
A 3,500-watt central AC unit run 8 hours a day at 16¢/kWh uses 28 kWh a day, costing about $4.48/day, or around $134 over a full month of summer use.
How much does a window unit cost versus central air?
A typical window unit (900-1,500 watts) run the same hours costs roughly a quarter to a third as much as a central system, since it's only cooling one room instead of the whole house.
Does thermostat setting change the cost much?
Yes — each degree you lower the thermostat below outdoor temperature typically adds 3-5% more runtime and energy use, so raising your set point from 68°F to 74°F can cut cooling costs noticeably.
How can I estimate summer-long AC cost?
Multiply the daily cost by your typical cooling season length — about 120 days is a common estimate for a moderate climate, more for hot regions and less for mild ones.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). How Much Does It Cost to Run an Air Conditioner?. Retrieved from https://www.revenuelab.fyi/toolbox/how-much-to-run-an-air-conditioner
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/how-much-to-run-an-air-conditioner" target="_blank" rel="noopener">How Much Does It Cost to Run an Air Conditioner? — RevenueLab</a> (2026).</p>
Source: [How Much Does It Cost to Run an Air Conditioner? — RevenueLab](https://www.revenuelab.fyi/toolbox/how-much-to-run-an-air-conditioner) (2026).