Last updated: July 7, 2026 · Prices reviewed quarterly
An AC that runs but does not cool usually has one of five culprits — and three cost under $400 to fix. Work this list in order before authorizing big-ticket repairs: filter, power, thermostat, coils, refrigerant, compressor.
Causes and 2026 repair costs
| Cause | Symptoms | Typical fix cost |
|---|---|---|
| Dirty filter / coils | Weak airflow, ice on lines | $0 – $150 (largely DIY) |
| Bad capacitor | Outdoor unit hums, fan will not start | $100 – $400 |
| Refrigerant leak | Warm air, hissing, ice, rising bills | $200 – $1,500 (find + fix + recharge) |
| Fan motor | Fan dead or screeching | $300 – $700 |
| Compressor | Breaker trips, unit will not engage | $1,500 – $3,000 |
The 30-minute homeowner checklist
1) Swap the filter — a clogged filter alone can ice the coil. 2) Check the breaker AND the outdoor disconnect. 3) Thermostat: cool mode, setpoint below room temp, fresh batteries. 4) Clear debris from the outdoor unit. 5) Gently rinse condenser coils (power off). Still warm after the coil thaws? Now the $75-$200 diagnostic is worth paying.
The refrigerant trap of 2026
“Topping off” without fixing the leak is renting cold air — refrigerant does not get consumed; it escapes. Mid-transition refrigerant economics have made recharges on older systems pricier, quietly rewriting repair-vs-replace math on aging units: run replacement numbers before a second recharge.
When “not cooling” means “replace”
Compressor failure out of warranty on a 12+ year unit is the textbook trigger — $1,500-$3,000 into a machine at end-of-life fails the age × repair test every time. Bigger picture: full HVAC replacement guide.
Official resources & free help
- Maintenance schedules that prevent this: Energy.gov AC maintenance
- Refrigerant rules (why pros must handle it): EPA Section 608 — epa.gov/section608
- Heat-wave help: dial 211 for cooling centers & LIHEAP referrals
FAQ
Ice on the pipes — keep running it?
No. Shut off, let it thaw for hours, replace the filter, then test. Running iced accelerates compressor death.
Cools in the morning, struggles at 4 pm?
Dirty condenser, undersizing, or hot-attic ductwork — coil cleaning is the cheap first fix.
Are $99 tune-up specials legit?
Often upsell loss-leaders, but the checklist has value. Require written findings with photos before approving discovered “repairs.”
Prices on this page are researched estimates compiled from the cited sources; your local costs will vary with market, access and scope. Always get multiple written quotes from licensed professionals before hiring.