How much does it cost to run an air conditioner in Idaho?

Short answer

A 3-ton central air conditioner in Idaho costs about $37.75 in July and $98.38 a year at 13.02¢/kWh; an 8,000 BTU window unit about $7.38 in July.

• Idaho pays 13.02¢/kWh on average for Jan–Aug 2026 — 28% below the U.S. average of 18.19¢, the 49th most expensive of the 50 states and DC.
• Idaho averages 456 cooling degree days a year against 1,216 nationally (NOAA), so we estimate 281 full-load cooling hours — 3.5 a day in July.
• A new 3-ton split system sold for Idaho must reach at least SEER2 13.4 (DOE northern region); it draws about 2.69 kW on average and $0.35 an hour.
• Moving up to the ENERGY STAR average of about SEER2 17 would cut the yearly bill to $77.55 — $20.83 a year less.
• The average Idaho home used 933 kWh a month in 2025; this system adds 290 kWh in July.