Cost to run

How much does a swamp cooler cost to run?

An evaporative cooler only powers a fan and a small water pump, so its electrical draw is a fraction of a refrigerated air conditioner's. The trade-off is that it works well only in dry climates.

Content reviewed 2026-07-15 · Rates published 2026-09-24 · methodology appliance-energy-1.0.0 · data vintage 2026-07-ytd

Using the window unit assumptions below, electricity costs about $0.29 per day of use and $8.67 for 30 days of use at the Texas average rate. Adjust the calculator for your equipment and schedule.

Example costs using the Texas state-average rate

These are generated examples for a consistent location. Enter your own ZIP and usage below for a more relevant state-average estimate.

Scenario	Assumption	kWh/month	Cost/day of use	Monthly range	Cost at 365 days/year
Small portable unit	6 hours a day for one room 100 W × 6 h/day × 0.9 duty × 30 days × 1 unit(s)	16.20	$0.09	$1.72–$3.85	$31.65
Window unit	8 hours a day for the main living area 250 W × 8 h/day × 0.9 duty × 30 days × 1 unit(s)	54.00	$0.29	$5.74–$12.82	$105.51
Whole-house cooler	10 hours a day on a rooftop system 700 W × 10 h/day × 0.95 duty × 30 days × 1 unit(s)	199.50	$1.07	$21.22–$47.37	$389.82

Wattage, runtime and duty cycle below are illustrative assumptions, not measurements of a particular model. Annual figures assume use on all 365 days; monthly figures use each scenario's stated number of days.

Source: U.S. Energy Information Administration, Electric Power Monthly Table 5.6.B. Data vintage 2026-07-ytd. State-average pricing is not your exact utility tariff.

Calculate your own usage

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Rated watts (from the appliance label)Duty cycle (0–1; share of time drawing full power)Days per month

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Where the electricity actually goes

Nearly all of a swamp cooler's draw is the blower fan, with a small pump keeping the pads wet. There is no compressor, which is why hourly consumption lands closer to a large fan than to an air conditioner.

Climate decides whether it works at all

Evaporative cooling drops air temperature by evaporating water, so performance collapses as humidity rises. In dry regions it can substitute for refrigerated cooling much of the season; in humid regions it mostly adds moisture without much cooling.

Costs this page does not include

Water consumption is real but priced by your water utility, not modeled here. Pad replacement, winterization, and the higher fan speeds some users run continuously are also outside the electricity-only scenario ranges shown above.

Frequently asked questions

How much cheaper is a swamp cooler than AC?

Its hourly electrical draw is typically several times lower because there is no compressor. Your actual savings depend on how many refrigerated-cooling hours it displaces in your climate.

Does a swamp cooler use a lot of water?

It continuously evaporates water while running, and usage varies with pad size, airflow, and dryness. Water cost is separate from the electricity estimated here.

Why is my swamp cooler ineffective on some days?

High humidity limits evaporation. On monsoon or muggy days the outlet air stays warm and damp, and many households switch to refrigerated cooling if available.

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