It is 105 degrees outside, your AC is running, but your house is getting warmer by the minute. This is one of the most stressful situations a Tucson homeowner can face. Before you panic, let us walk through the most common reasons your AC is not cooling and what you can do.
Check the Easy Things First
Before calling for AC repair, check these common issues that you can fix yourself. First, look at your thermostat. Make sure it is set to cool mode and the temperature is set below the current room temperature. It sounds obvious, but accidental thermostat changes are one of the most common reasons people call for service. Second, check your air filter. A severely clogged filter can restrict airflow enough to make your system blow warm air. If the filter is dirty, replace it and give the system 30 minutes to recover.
Dirty or Blocked Condenser Unit
Your outdoor condenser unit needs clear airflow to release heat from your home. In Tucson, desert debris, dust, leaves from palo verde and mesquite trees, and even pack rat nests can obstruct the condenser. Walk outside and inspect the unit. If the fins are caked with dust or there is debris blocking airflow, carefully clean it with a garden hose. Make sure there is at least two feet of clearance on all sides.
Refrigerant Leak
If your AC is blowing air but it is not cold, a refrigerant leak is one of the most likely causes. Signs of a refrigerant leak include ice forming on the refrigerant lines or evaporator coil, hissing or bubbling noises near the indoor unit, and gradually decreasing cooling performance over days or weeks. Refrigerant leaks require professional repair — this is not a DIY fix. A technician will need to find the leak, repair it, and recharge the system.
Frozen Evaporator Coil
A frozen evaporator coil will stop your AC from cooling effectively. This can be caused by restricted airflow from a dirty filter, low refrigerant levels, or a malfunctioning blower fan. If you suspect a frozen coil, turn the AC off but leave the fan running to help thaw it. Once it thaws, check the filter and call a technician if the problem returns.
Failing Compressor
The compressor is the heart of your AC system. When it starts to fail, cooling capacity drops noticeably. You might hear clicking, rumbling, or hard-starting sounds from the outdoor unit. Compressor replacement is one of the most expensive AC repairs, and on older systems it often makes more sense to replace the entire unit.
Undersized System Struggling in Extreme Heat
Some AC systems in Tucson simply were not sized correctly for the home. A system that keeps up fine at 95 degrees may fall behind at 110 degrees. If your AC consistently fails to maintain your set temperature on the hottest days, the unit may be too small for your home or your ductwork may be undersized. A professional load calculation can identify whether this is the issue.
Ductwork Problems
Leaky or disconnected ductwork in your attic can dump cooled air into unconditioned spaces. In a Tucson attic that reaches 150 degrees or more, even small duct leaks can dramatically reduce cooling performance. If some rooms are cool but others are warm, ductwork is a likely culprit.
When to Call for Help
If checking the thermostat, filter, and outdoor unit does not solve the problem, it is time to call a professional. In Tucson's extreme heat, going without AC can be a health hazard. ABC Water & Air offers fast, reliable AC repair across Tucson and surrounding areas. Call (520) 812-1597 and we will get your system back to work.