Swamp Cooler vs. AC Running Cost Calculator

This calculator answers a narrower question than most: what does it cost in electricity to cool your house for one summer month, and what would the same month cost on refrigerated air? Pick the house size, how many hours the cooler actually runs in July, and what you want to compare against. There is no email gate and the number updates as you change the dropdowns.

The starting range is a whole-house evaporative cooler in a 1,200 to 2,000 square foot Reno home running about 12 hours a day, priced at the Energy Information Administration’s published Nevada residential average of 13.11 cents per kilowatt-hour for June 2026. Everything the math assumes is written on the tool itself rather than buried, because a cooling-cost calculator with hidden assumptions is a sales tool, not a calculator.

What each answer changes

House size scales the cooler. A window or small side-draft unit is a smaller motor and a smaller pump; a big two-speed down-draft on a 3,000 square foot house moves far more air and draws accordingly. The multiplier tracks motor size, not floor area directly.
Hours per day is the honest variable, and the one Reno households get to choose more than most. With a July normal low of 60.4 degrees, a lot of coolers here run from noon to bedtime and shut off overnight, which is the 12-hour setting. During a heat advisory, like the August 21 to 23, 2025 stretch when the Weather Service reported temperatures to 103, a lot of them never go off at all.
Comparison target swaps the equipment while holding the house and the hours constant. A one-zone mini-split is counted at about 1 kW while it modulates. Central air is counted at about 3.2 kW with the compressor cycling roughly two thirds of the hours, which is why it lands near three and a half times the cooler rather than five.

Reading the result honestly

Three things this number does not include. It does not include water, which the cooler uses and refrigerated air does not. It does not include seasonal labor: a cooler needs a spring start-up and a fall winterization every year, plus pads, and central air does not. And it does not include the installed cost of the equipment, which is where the real gap sits: $6,000 to $15,000 for central air or $3,500 to $8,000 for a one-zone mini-split against $1,500 to $4,000 for a new cooler.

It also does not price comfort. A cooler cannot pull air much below the wet-bulb temperature, so on the few monsoon afternoons a year when moisture pushes up to Reno, the running-cost winner is also the system sitting in a sticky living room. That is a real trade, and the cooler versus refrigerated air page walks it through without pushing anyone in either direction. Reno’s short summer, with 90 degree days concentrated in July and August, keeps the season total for all three systems lower than the desert cities.

If what you actually want to know is what a repair costs rather than what a month costs, use the repair cost calculator instead, and the pricing page has every published range on one screen.

Running cost

What does it cost to cool this house for a month?

Three questions. The starting number is a whole-house evaporative cooler at Nevada's average residential electricity price in a Reno July. Switch the last dropdown to see what the same house costs on refrigerated air.

How big is the house? Hours run per day in July Compare against

Estimated monthly running cost July electricity only, before any repair or maintenance

Assumptions, stated plainly. The cooler is a 1/3 to 3/4 horsepower two-speed blower plus a small submersible pump, about 400 to 800 watts in normal use. Phoenix Manufacturing's AeroCool tables list those motor sizes at 7.4 to 11.5 nameplate amps on 120 volts, which is the high-speed maximum rather than the usual draw. Electricity is priced at 13.11 cents per kilowatt-hour, the U.S. Energy Information Administration's published average residential price for Nevada in June 2026. Your NV Energy bill has a fixed charge and seasonal rates on top of that, so treat this as the marginal cost of running the equipment.

Send this comparison to the quote form

An estimate of electricity only, not a quote, and not a promise about your bill. It does not include water, pads, pumps, seasonal service, or the installed cost of new equipment. Ranges are rounded to the nearest $5.

Frequently Asked Questions

Where does the 13.11 cents per kilowatt-hour come from?

From the U.S. Energy Information Administration's Electric Power Monthly, which reports the average residential retail price of electricity by state. For Nevada it was 13.11 cents per kilowatt-hour in June 2026, up from 12.26 a year earlier. It is a statewide average, not your tariff, so the number to compare against is the per-kilowatt-hour line on your own NV Energy bill.

Why does the cooler use so much less?

Because it runs a fan and a small pump instead of a compressor. A whole-house evaporative cooler is a 1/3 to 3/4 horsepower blower motor and a submersible pump; a 3-ton central air system is a compressor plus an indoor blower. The physics gap is about five to one on draw, and about three and a half to one once you account for the compressor cycling rather than running continuously.

Does this include the water the cooler uses?

No. A cooler evaporates water and bleeds or purges more to keep mineral out of the pan, which is a real cost, but on a TMWA bill it is small next to the electricity. On a private well outside the TMWA system the cost is pumping, not the water itself.

Should I convert to refrigerated air based on this?

Not on running cost alone. Running cost is the half where the cooler wins by a wide margin, every year. The half it loses is comfort on the handful of monsoon afternoons a Reno summer gets, and the cooler versus refrigerated air page covers the installed costs and the honest trade.