Estimate the electricity cost of running an air conditioner in the United States. Use the method that matches the data you have: known electrical input, room-air-conditioner cooling capacity plus CEER, or annual kWh from an EnergyGuide or product listing.
Estimate air-conditioner running cost
Choose the method that matches the information you have.
Electricity rate
Which calculation method should you use?
Known electrical input
Use this when you know the air conditioner’s approximate electrical draw in kilowatts. This is the most direct method for estimating cost per operating hour. Real inverter equipment can draw less or more as load and outdoor conditions change.
Room AC: BTU/h and CEER
ENERGY STAR room-air-conditioner listings commonly provide cooling capacity in Btu/h and a Combined Energy Efficiency Ratio (CEER). Dividing cooling capacity by CEER gives an approximate rated electrical input in watts. This method is intended for room air conditioners.
Annual kWh
If an EnergyGuide label, ENERGY STAR listing or manufacturer document provides annual electricity use, enter that kWh figure directly.
Why HomeBillLab does not convert SEER2 directly to exact cost per hour
SEER2 is a seasonal cooling-efficiency metric. Actual central-air-conditioner power draw varies with equipment capacity, weather, indoor load, fan operation, cycling and modulation. For an hourly estimate, use known electrical input when available. For an annual estimate, use tested annual kWh when available.
Official U.S. references
- ENERGY STAR — Room Air Conditioners
- ENERGY STAR — Room Air Conditioner Key Product Criteria
- ENERGY STAR — Certified Room Air Conditioners
- EIA — residential electricity prices by state
Reviewed: 26 September 2026. State benchmark rates use EIA July 2026 residential average retail prices.
Air conditioner running cost FAQs
Does a 1.5 kW air conditioner always draw 1.5 kW?
No. Many modern systems modulate output, and actual input changes with load and operating conditions.
Can I use CEER for central air conditioning?
No. The CEER method in this calculator is intended for room air conditioners. For central systems, use known electrical input or annual kWh data instead.
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