AC Not Blowing Cold Air? 5 Causes, Fixes $75 to $1,500

AC not cooling: symptoms, causes and fix costs

Prices from HomeGuide's AC repair guide (Aug 2025) and HomeAdvisor (June 2026). Add a $75 to $200 service call.

Do this now: AC not blowing cold air

Check on people before the AC: above 90 F indoors, the CDC says a fan can raise body temperature, and it names people 65 and older, infants and young children, and people with asthma or heart disease among those at higher risk. Get them somewhere cool; dial 2-1-1 to find air conditioning.

1. Heat stroke signs? A body temperature above 103 F, hot red dry skin, a fast strong pulse or confusion: call 911 first (Ready.gov).
2. Ice on the copper lines or water on the floor? Switch the thermostat from Cool to Off and run the fan. Do not chip the ice; Bryant says it can take several hours to thaw.
3. Breaker tripped? Reset the AC breaker once. If it trips again, leave it off and tell the company.
4. Thermostat and filter. Cool mode, set below room temperature, and a clean filter. The four safe checks below cover each step.
5. Still blowing warm? Call the heating and AC line and say what you checked. HomeGuide puts the service call at $75 to $200.

Safe checks before you call

Four checks cover the most common causes, and none of them involve opening the equipment:

1. Thermostat. Set to Cool, set below the room temperature, fan on Auto. Replace the batteries if the screen is blank. ENERGY STAR lists thermostat settings first on its maintenance checklist.
2. Air filter. ENERGY STAR says to inspect, clean or change filters once a month and that a dirty filter can damage the equipment. The DOE says replacing a clogged filter can cut AC energy use 5% to 15%.
3. Breaker. Check the panel for a tripped AC or air handler breaker and reset it once. If it trips again, stop and call; see breaker keeps tripping.
4. Outdoor unit. Clear leaves, grass and debris from around it. The DOE says to trim foliage back at least 2 feet.

Why is my AC not blowing cold air, or blowing hot air?

Warm air from the vents most often means the outdoor unit is not running or the system is low on refrigerant. Check the thermostat and the breaker first; past that it needs a technician's diagnosis. Electrical parts in the outdoor unit are among the cheaper fixes on HomeGuide's list: a capacitor at $100 to $250 or a contactor at $200 to $450. HomeGuide lists warm air from the vents as a sign of low refrigerant, and says an AC never needs more refrigerant unless there is a leak. Leak repair costs $200 to $1,500 in HomeGuide's guide.

AC running but not cooling

An AC that runs constantly without reaching the setting is usually short on airflow or refrigerant. A clogged filter or dirty coils restrict air; ENERGY STAR says dirty coils reduce the system's ability to cool. HomeGuide puts coil cleaning at $100 to $400. The DOE says to call a technician when the unit does not bring the indoor temperature to a comfortable level, and that the technician should check the refrigerant charge and test for leaks.

AC freezing up

Full guide: why an AC keeps freezing and how to unfreeze it.

Ice on the indoor coil or the copper lines means restricted airflow or low refrigerant, according to both Lennox and Bryant. Lennox adds that running the AC when it is below about 60°F outside can also freeze it. What to do:

1. Switch the thermostat from Cool to Off.
2. Set the fan to On so air moves over the coil while it thaws, if your system allows it. Bryant says thawing can take several hours.
3. Do not chip or scrape the ice; Bryant says to let it thaw.
4. Replace the filter and open any closed supply or return vents.
5. Put towels down: Bryant notes melting ice can make a lot of water.
6. Restart only after the ice is gone. If it freezes again, call. Lennox says repeated freezing after the filter and vents are fixed needs a technician.

AC leaking water

Full guide: why an AC leaks water and how to unclog the drain line.

Water around the indoor unit is usually a clogged condensate drain. ENERGY STAR says a plugged drain can cause water damage in the house and affect humidity, and the DOE says clogged drain channels can discolor walls or carpet. A professional drain flush costs $75 to $250 in HomeGuide's guide, a condensate pump $100 to $450, and a drain pan $200 to $600. If water has reached a ceiling below an attic air handler, see ceiling water damage repair; for wet floors or walls, water damage restoration.

AC not turning on or not working at all

Full guide: AC not turning on, and how to reset it.

A dead system starts with power and the thermostat. Check the thermostat display and batteries, then the breaker. HomeGuide prices a fuse or breaker repair at $75 to $300 and a new thermostat at $140 to $350 installed. If power is on and it still will not start, call. HomeGuide prices the common electrical fixes at $100 to $250 for a capacitor and $200 to $450 for a contactor, and a fan motor at $200 to $700.

Repair or replace if your AC is not working

If the fix is a capacitor or a drain line, repair it. If the diagnosis is a compressor or a coil on an older unit, price both options. HomeAdvisor and HomeGuide both suggest replacing when the unit is over 10 years old, uses R-22, or the repair cost times its age passes $5,000. AC repair lists every common fix, and AC replacement cost has new system prices.

When an AC that is not cooling becomes an emergency

A broken AC is an emergency when someone in the house is at risk from heat. The CDC says people 65 and older, infants and young children, and people with asthma or heart disease are at higher risk, and that fans can raise body temperature once it is above 90°F indoors. Dial 2-1-1 to find a place with air conditioning, and call 911 for signs of heat stroke. Emergency HVAC repair has the full list and after-hours rates.

For prevention, ENERGY STAR recommends a cooling check every spring. If the ducts are the question, see duct cleaning; for heat pumps, heat pump repair. Prices for every trade are on home repair costs, and the HVAC repair hub covers furnaces too.

Calls go to an independent company that serves your area and takes this kind of job. Ask for its license number and proof of insurance yourself. How calls work.