Cooling · California
How Much Does It Cost to Run a Window Air Conditioner in California?
The short answer
In California, a window air conditioner drawing 900W costs about $0.30 per hour — roughly $73.61 a month if it runs 8 hours a day.
The estimate uses California’s average residential electricity price of 33.6¢/kWh from EIA (July 2026) — 84% above the national average.
Source: U.S. EIA, July 2026 data · Updated
Window Air Conditioner cost by daily use in California
| Daily use | kWh/month | Per day | Per month | Per year |
|---|---|---|---|---|
| 1 hour/day | 27.4 | $0.30 | $9.20 | $110 |
| 2 hours/day | 54.8 | $0.60 | $18.40 | $221 |
| 4 hours/day | 109.5 | $1.21 | $36.81 | $442 |
| 8 hours/day | 219.0 | $2.42 | $73.61 | $883 |
| 12 hours/day | 328.5 | $3.63 | $110 | $1,325 |
| 24 hours/day | 657.1 | $7.26 | $221 | $2,650 |
California vs other states
At typical use, a window air conditioner costs $883 a year in California — $378 less than in Hawaii and $549 more than in Louisiana.
California has the 2nd-most-expensive residential electricity of the 50 states and DC. California price per kWh · all states ranked
Electricity price trend in California
33.6¢/kWh in July 2026 — ▲ +2.9% from a year earlier.
How to lower the cost of running a window air conditioner
Window air conditioners cool a single room and are far cheaper to run than central AC when you only need one or two rooms cool. Wattage scales with capacity: small 5,000 BTU units draw around 450–500W, a 10,000 BTU unit around 900W, and large 15,000+ BTU units 1,300–1,500W. ENERGY STAR models with inverter compressors can use 20–35% less. The compressor cycles with the thermostat, so enter the hours it actually runs.
- Pick the right size — an oversized unit cycles constantly and dehumidifies poorly.
- Seal the gaps around the unit with foam strips to keep hot air out.
- Clean the washable filter every two weeks in peak season.
Questions
Frequently asked questions
How much does it cost to run a window air conditioner for 24 hours in California?
Running a 900W window air conditioner for 24 hours uses about 21.6 kWh, which costs about $7.26 at California’s average rate of 33.6¢/kWh.
How many kWh does a window air conditioner use per month?
At 8 hours a day, a typical window air conditioner uses about 219 kWh a month. In California that costs $73.61.
Is it expensive to run a window air conditioner in California?
California has the 2nd-most-expensive residential electricity of the 50 states and DC at 33.6¢/kWh — one of the most expensive. Running a window air conditioner here costs about $883 a year at typical use, compared with $481 at the national average rate.
What is the electricity rate in California right now?
The average residential electricity rate in California was 33.6¢ per kWh in July 2026, according to the latest EIA data — up 2.9% from a year earlier.
Is a window AC cheaper to run than central air?
For cooling one or two rooms, yes. A 900W window unit uses about a quarter of the power of a typical 3,500W central system.
Window Air Conditioner costs in nearby states
Other appliances in California
Cheapest and priciest states
Comparisons
Sources & method
- Electricity rates: U.S. Energy Information Administration, Electric Power Monthly — average residential retail price, July 2026 (latest available). Retrieved .
- CO₂: EIA State Electricity Profiles, 2024 emissions rate of in-state power generation.
- Default usage for window air conditioner: 8 hours a day. Typical power 900W.
- Formulas, duty cycles and limitations: methodology. Data download: open data (CC BY 4.0).