What does a central air conditioner cost to run?

Run the numbers on your own use

Change any of these and the figures update. The defaults are the typical case described above; your rate is the input that moves the answer most.

Why this is lower than the number you will see elsewhere

Almost every published answer to this question multiplies the rating on the label by the hours the appliance is switched on. For a central air conditioner that gives 3,780 kWh a year, or $693.

A correctly sized system runs 50–70% of the time on a design-temperature day and far less on a mild one.

The arithmetic, step by step

Nothing here is hidden, so you can check it or change it. Working in the order the formula runs:

1. 3,500 W — what it draws while it is actually drawing. This is the rating on the plate.
2. × 60% — the share of its in-service time it is really pulling that. A correctly sized system runs 50–70% of the time on a design-temperature day and far less on a mild one.
   That gives 2100 W averaged across the hours it is on.
3. × 9 hours a day × 120 days — A 3-ton system in a hot-summer climate.
   2100 × 9 × 120 ÷ 1,000 = 2,268 kWh a year.
4. + standby — 15 W for the other 15.0 hours a day, which is 27 kWh a year. People leave this out and it is not always small.
5. × 18.34¢ — the US average residential rate for June 2026.
   2,295 kWh × 18.34¢ = $421 a year.

Change any assumption in the calculator above and every figure on this page moves with it. The two that matter most are your rate, which varies 4× across the country, and the hours — the duty cycle is a property of the appliance, but the hours are a property of you.

How sensitive is that number?

A single figure invites more confidence than it deserves. Here is the same appliance under assumptions either side of the default, so you can see how much of the answer is the appliance and how much is the guess about how you use it.

Everything else held at the default. The spread here is the honest error bar on the headline figure.

What it costs per hour, day and month

At 18.34¢ per kWh, the US residential average for June 2026.

The thing worth knowing

Cooling is the end use with the widest spread in the country: RECS puts the hot-humid average at 4,173 kWh a year against 902 kWh in the marine climate zone. A national average cooling cost is close to meaningless.

Against ceiling fan

Raising the setpoint by 1 degree F cuts cooling energy by roughly 3–5%. A variable-speed system holds temperature at part load instead of cycling, which is where most of the efficiency gain in modern units comes from. In numbers: a central air conditioner costs $421 a year on these assumptions, and ceiling fan doing a comparable job costs $9.77 — a difference of $411 a year, or $4,111 over ten years at today’s rate.

Both at 18.34¢/kWh, each on its own standard usage assumption. Ten years is roughly the service life of either.

What it costs in your state

The appliance is the same everywhere; the rate is not. Running this central air conditioner costs $1,210 a year in Hawaii and $301 in Nevada — a difference of 4×.

Cost of running one central air conditioner for a year, by state. Residential average price, EIA June 2026.

Other heating and cooling costs

• Electric furnace

  $1,653 a year

  Whole-home resistance heating in a cold climate.

• Heat pump (heating)

  $423 a year

  Whole-home heating in a mixed climate.

• Dehumidifier

  $228 a year

  A 50-pint unit holding a basement at 50% relative humidity.

• Electric baseboard heater

  $218 a year

  One 1,000 W baseboard unit in one room. Most homes have several.

• Heated towel rail

  $193 a year

  Left permanently on, which is how most of them are used.

• Furnace blower / air handler

  $189 a year

  A single-speed PSC blower running with the heating and cooling seasons.

Questions

Source: U.S. Energy Information Administration, Electric Power Monthly, Table 5.6.A, June 2026. U.S. Government work, public domain.

How every figure on this page is computed · Where the data comes from