Air conditioning in Phoenix works harder than in most of the country. Long, very hot summers mean systems run many hours a day for much of the year, and dust is hard on filters and outdoor coils. This guide covers what usually goes wrong, what you can safely check first, and how to find help.
Quick checks before you call
- Make sure the thermostat is set to Cool and the set point is below the room temperature. Replace thermostat batteries if it has them.
- Check the breaker panel for a tripped breaker for the air handler or the outdoor unit. Reset it once. If it trips again, leave it off and call a professional.
- Replace a dirty air filter. A clogged filter is one of the most common causes of weak airflow and frozen coils.
- Look at the outdoor unit. Clear leaves, grass clippings and debris away from it.
- Check that supply and return vents are open and not blocked by furniture.
Common causes of AC trouble in the Valley of the Sun
- Dust-clogged filters and outdoor coils, which cut airflow and make the system work harder in extreme heat.
- Failed capacitors or contactors in the outdoor unit.
- Low refrigerant caused by a leak.
- Dirty evaporator or condenser coils.
- Duct problems in hot attics.
See our guides on AC not cooling, frozen coils, warm air and leaks.
Repair or replace?
Older systems with major failures, such as a compressor, may be worth replacing instead of repairing. Our replacement cost guide explains what drives price. A licensed contractor can give you an estimate for your home.
Choosing a contractor
In Arizona, contractors, including HVAC contractors, are licensed by the Arizona Registrar of Contractors (ROC). Before you hire anyone, look up their name or license number at roc.az.gov and ask for proof of insurance. Ask for a written estimate, ask what the warranty covers, and do not feel pressured to decide on the spot.
Monsoon season
Arizona’s monsoon season runs June 15 to September 30 and can bring dust storms, high winds, heavy rain and power outages. After a storm, clear debris from the outdoor unit. If it was flooded or damaged, turn the system off and have it inspected before you run it.
Get matched with a local AC contractor
Tell us what is going on and where you are, and you can ask an independent AC contractor serving your area to contact you. It is your choice, and our service is free to you. Ask a local pro to contact you.
Phoenix AC Match is an independent referral service, not an HVAC contractor. We do not perform repairs or installations, and we may be paid by the contractors we refer you to. See our Referral & Advertising Disclosure.