Book a service call now for a 5-star experience.Your AC runs and runs but the house stays stuck at 80 degrees. The thermostat is set to 72 but it never gets there. This is frustrating and confusing. The system seems to be working. You hear it running. Air comes out of the vents. But the temperature will not drop. This guide explains why this happens and what you can do about it, or give us a call directly to have a professional technician diagnose the issue.
Air conditioners are designed to cool your home about 20 degrees below the outdoor temperature. On a 95 degree day, your AC should be able to reach 75 degrees inside. On a 100 degree day, getting to 80 degrees might be the best it can do.
Here is a simple test: Check the temperature of the air coming out of your supply vents. Use a thermometer or even your hand. The air should be 15 to 20 degrees cooler than the air going into the return vent.
If the air coming out is nice and cold (around 55 to 60 degrees), your AC is working correctly. The problem is somewhere else. Your home might have insulation issues, duct leaks, or the system might be undersized.If the air coming out is only slightly cool (70 degrees or warmer), something is wrong with the AC itself. It is not removing enough heat from the air.This simple test tells you where to focus your troubleshooting.
Check your air filter – A clogged filter is the number one cause of poor cooling. When the filter is dirty, air cannot flow through properly and your AC starves for air.
Check your thermostat settings – Make sure the fan is set to "auto" and not "on" because when set to "on," the fan runs constantly even when the AC is not actively cooling. This blows unconditioned air and makes it feel like the AC is not working well.
Check your vents – Walk through your home and make sure all supply vents are open. Closed vents in unused rooms seem like a good idea but they actually hurt your system's performance.
Check your outdoor unit – Go outside and look at your condenser unit. Is it covered in leaves, dirt, or debris? Is grass or bushes growing up against it? Clear any debris and trim vegetation back at least two feet. You can gently rinse the coils with a garden hose by spraying from the inside out.
Low refrigerant - Refrigerant does not get used up like gas in a car, so if it is low, you have a leak somewhere. A technician needs to find the leak, repair it, and recharge the system with the correct amount.
Dirty evaporator coil - Over time, dust and dirt build up on the coil and this layer acts like insulation that prevents heat transfer. Your AC runs but does not remove heat effectively. Evaporator coil cleaning requires professional service because the coil is hard to access and easy to damage.
Dirty condenser coil - When the condenser coil gets caked with dirt, it cannot release heat efficiently and the system works harder but accomplishes less. You can rinse it yourself with a hose, but heavy buildup may need professional cleaning with specialized chemicals.
Duct Leakage - Studies show that typical homes lose 20 to 30 percent of cooled air through duct leaks, which is like paying for air conditioning and throwing a third of it away.
Your AC may be low on refrigerant, have dirty coils, be undersized for your home, or have duct leaks. It could also be struggling against extreme outdoor heat since a system can only cool about 20 degrees below the outdoor temperature.
Yes, a dirty filter restricts airflow which reduces your AC's ability to absorb and remove heat. This is the most common cause of poor cooling and the easiest to fix.
A properly sized AC should lower the temperature about 1 degree every 20 to 30 minutes. Cooling from 85 to 72 degrees should take 3 to 4 hours, and if it takes much longer, something is wrong.
On extreme heat days over 100 degrees, some AC systems cannot maintain 72 degrees and reaching 78 to 80 might be the best they can do. But if your AC struggles on moderate days in the 90s, something is wrong.
Common causes include dirty air filter, low refrigerant, dirty coils, duct leaks, or an undersized system. Start by checking your filter and outdoor unit, and if those are fine, call a professional.