How to use this calculator
Cooling equipment cycles with temperature, humidity, insulation, and thermostat settings. Use electrical input watts—not cooling capacity in BTU—to estimate the cost of active compressor time.
- Use rated input watts or measured draw.
- Estimate compressor runtime during a typical cooling day.
- Compare mild- and hot-month scenarios.
FORMULA
The math behind the estimate
input watts × compressor runtime ÷ 1,000 × electricity rate = operating cost.
Worked example
A 3,500 W system running eight hours a day at $0.18/kWh costs about $153 in an average month.
Change the defaults to model your home. The result is an estimate, not a guaranteed bill or savings promise.
How to read the result
Use the estimate to compare scenarios and find the inputs worth measuring more carefully. Utility bills can include fixed charges, taxes, delivery fees, minimums, tiers, and demand charges that are not fully represented by a simple energy rate.
Assumptions and limitations
- Runtime means active compressor operation.
- Fan-only energy and tiered rates may differ.
- Weather can materially change monthly use.
Climate, equipment condition, installation, controls, and household behavior can materially change results. Verify consequential installation and purchasing decisions with qualified providers.
Practical savings context
Start with thermostat schedules, clean filters, sealed ducts, and shade. Equipment replacement decisions should use a qualified load calculation.
SOURCE
Data and methodology
U.S. Department of Energy — Air Conditioning
Guidance accessed August 2026. Geographic scope: United States. Last reviewed: August 6, 2026.
WattMeasure uses the source to frame the method and assumptions; your editable inputs determine the displayed result.
QUESTIONS
Air conditioner FAQ
How accurate is this air conditioner estimate?
It is a planning estimate based on the values you enter. Actual power draw, cycling, utility charges, climate, and equipment condition can change the result.
Should I use the default electricity rate?
Your own marginal or all-in supply rate is better. Check a recent bill or your utility's published rate schedule.
Does this include taxes and utility fees?
Only when they are reflected in the rate you enter. Fixed monthly charges are not included because they usually do not change with one appliance's usage.
Last reviewed August 6, 2026 · Data update policy