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Cooling

Fan vs Air Conditioner Cost Calculator

A fan is normally much cheaper to run than air conditioning, but it moves air instead of lowering room temperature. Enter both setups to compare their electricity cost on the schedule you would actually use.

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Your details

W each

Use the rated watts from the fan label. Many room fans are roughly 25–100 W.

h
BTU/h

Use cooling capacity, not electrical watts. 12,000 BTU/h is one ton.

BTU/Wh

Use EER/EER2 for this operating-point estimate—not seasonal SEER/SEER2.

h

A cycling or variable-speed AC may run longer while averaging less than full input. Estimate equivalent full-load hours.

days
$ /kWh

Results

Fan cost per day
AC cost per day
Fan cost per month
AC cost per month
Monthly electricity-cost difference

Positive means the fan setup costs less. This compares electricity only, not equal cooling performance.

AC-to-fan cost ratio

The schedules can differ, so this is a cost ratio—not an efficiency rating.

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Written & maintained by the HowMuchWatts team · Last updated July 18, 2026 · How we verify our numbers

How it works

Total fan watts = watts per fan × number of fans. AC full-load input watts = cooling capacity in BTU/h ÷ EER. Daily cost = watts ÷ 1,000 × hours per day × electricity rate. Monthly cost = daily cost × cooling days. The difference is AC monthly cost minus fan monthly cost; the ratio is AC monthly cost ÷ fan monthly cost.

Example fan and AC running costs

These examples assume 8 hours of use per cooling day, 30 cooling days and electricity at $0.17/kWh. AC rows are full-load input examples; thermostatic cycling can reduce actual energy use.

Cooling deviceExample inputDaily cost30-day cost
Efficient room fan35 W$0.05$1.43
Standard room fan50 W$0.07$2.04
Box or pedestal fan75 W$0.10$3.06
12,000 BTU/h AC at EER 121,000 W$1.36$40.80
12,000 BTU/h AC at EER 101,200 W$1.63$48.96

The fan and AC do different jobs: a fan increases air movement around people, while an air conditioner removes heat and moisture from indoor air. Compare cost only after deciding which level of cooling is safe and adequate.

Worked example: 50 W fan vs 12,000 BTU air conditioner

With the default inputs, one 50 W fan used for 8 hours costs 50 ÷ 1,000 × 8 × $0.17 = $0.068 per day, or $2.04 across 30 cooling days. A 12,000 BTU/h air conditioner at EER 12 has an estimated full-load input of 1,000 W and costs $1.36 per 8-hour equivalent full-load day, or $40.80 across 30 days.

The electricity-cost difference is $38.76 per month, and the AC example costs 20 times as much to run on these schedules. That does not mean the fan delivers the same result: it does not lower room temperature or remove humidity.

When a fan can reduce AC cost

Air movement can make occupants comfortable at a higher thermostat setting, so a fan and AC can be cheaper than keeping the AC at a colder setting. The saving comes from reducing compressor work—not from the fan creating cold air. Turn room fans off when nobody is present because their comfort benefit is for people, not the empty room.

This calculator does not guess the thermostat-related saving because weather, humidity, insulation, equipment size and cycling make it home-specific. Compare measured AC kWh before and after a consistent thermostat change for a real result.

Extreme-heat safety matters more than the cheapest option

A low operating cost is not a reason to rely on a fan when indoor heat is unsafe. The CDC says to use fans only when indoor temperatures are below 90°F; above that level a fan can increase body temperature. During dangerous heat, use air conditioning or reach an air-conditioned location, stay hydrated and check on people at higher risk.

This is a cost comparison, not medical guidance. Follow local heat alerts and current public-health advice.

Use equivalent full-load hours for a fairer AC estimate

Air conditioners cycle their compressors and variable-speed models can run below full input. Eight clock hours switched on is not always eight full-load hours. If a 1,000 W unit averages 500 W over an eight-hour window, that is roughly four equivalent full-load hours.

The most reliable input is measured kWh over a representative day. A plug-in monitor can measure many window and portable AC units if the monitor is properly rated; central systems generally require manufacturer data or a professionally installed circuit monitor.

Sources used for assumptions: CDC extreme-heat fan and air-conditioning guidance; U.S. Department of Energy home-cooling guidance; ENERGY STAR ceiling-fan product criteria.

Frequently asked questions

Is it cheaper to run a fan or an air conditioner?

A fan is normally far cheaper because room fans often use tens of watts while air conditioners use hundreds or thousands. The two are not equivalent: AC lowers temperature and humidity; a fan mainly increases air movement around people.

How much cheaper is a fan than AC?

In the default example, a 50 W fan costs $2.04 for 30 eight-hour days while a 1,000 W AC costs $40.80—20 times as much. Enter your actual equipment and schedules because wattage and cycling vary.

Is it cheaper to run a fan and AC together?

It can be if the fan lets you raise the thermostat enough to reduce AC compressor energy by more than the fan uses. Measure daily AC kWh before and after the change for your home.

Does a fan cool a room?

A room fan normally cools people through air movement and evaporation; it does not remove heat from the room. Turn it off in an empty room.

Can I use a fan instead of AC during extreme heat?

Do not choose based on cost alone. The CDC advises using fans only below 90°F indoors and using air conditioning or an air-conditioned location when conditions are dangerously hot.

These calculators provide general estimates for educational purposes only and are not financial advice. Real-world results depend on factors not captured here. Verify figures independently before making any purchase or financial decision.

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