Cost to run air conditioning in Delaware
A 2.5-ton central unit costs about
$0.41an hour · $236 a year
That is 2,098 watts while the compressor runs, at 19.38¢ a kilowatt hour — Delaware's current residential rate.
Across a year
Electricity used
1,218 kWh
Full-load hours
581
Delaware runs about 1,200 cooling degree days a year. An air conditioner cycles rather than running flat out, so 581 full-load hours is the honest way to put it: the same energy as running at full capacity for that long. At that rate cooling is roughly 12% of a typical Delaware household's yearly electricity spend.
What actually changes this
Floor area and efficiency move this figure more than habits do. A home twice this size costs roughly twice as much to cool, and a unit at SEER2 20 instead of 14.3 uses about a third less. The thermostat matters least of the three — each degree cooler adds a few percent, not a multiple.
Common questions
How much does it cost to run AC for an hour in Delaware?
About $0.41 an hour for a 2.5-ton central unit drawing roughly 2,098 watts, at Delaware's residential electricity price of 19.38¢ per kilowatt hour.
What does air conditioning cost per summer in Delaware?
Roughly $236 a year for a 1,800 square foot home, which is about 1,218 kilowatt hours. Delaware runs around 1,200 cooling degree days a year.
Is it cheaper to leave the AC on all day or turn it off?
Turning it off while the house is empty is cheaper. An air conditioner works against the temperature difference between inside and outside, so a warmer empty house loses less heat gain than a cool one, and the extra cost of cooling back down is smaller than the saving.
Work it out for your home
These figures describe a 1,800 square foot home with a minimum-efficiency unit. Yours is not that home.
Electricity price from the US Energy Information Administration, residential sector, 2026-05. Cooling load estimated from Delaware's cooling degree days with an adjustment for humidity. An estimate, not a bill — insulation, ductwork, shading and how long anyone is home all move it.