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Why Isn’t My Air Conditioner Working? Your Common Cooling Problems Answered

Prepare for warmer weather with answers to the most common cooling system questions.

August 13, 2023

Spring is here and summer is just around the corner. Depending on where you live, temperatures are already reaching the 80’s — so having an air conditioner you can count on is key. What should you do if yours doesn’t work? We’ve got troubleshooting tips for this and more common cooling questions.

Why isn't my air conditioner working?

ANSWER: Your thermostat is not calibrated properly or set too high
Before calling a dealer, make sure your thermostat is set to cool. Especially at the beginning of a new season, your thermostat may still be in heating mode. Try setting the temperature 2 to 4 degrees below room temperature.

ANSWER: The circuit breaker might have been tripped
Try resetting it.

ANSWER: Clean or replace your filters
Sometimes filters can get clogged and keep cool air from circulating. That’s why we recommend routinely checking and cleaning or replacing your filters as needed. You can use the owner’s manual to find where your air filters are located in your unit. Or contact your local Trane Comfort Specialist™ if you’re unsure.

Why is my A/C blowing warm air?

ANSWER: You’re low on freon
If your air conditioner is running properly, you shouldn’t have to replace freon. However, refrigerant leaks can happen over time, and at $75-$100 a pound, you don’t want to wait to find the source of the leak. You’ll need an expert to evaluate your system, repair the cause of the leak and restore your freon level. Don’t let a dishonest dealer fill your freon level and leave — you’ll just have to pay to refill it again soon. Trust a Trane Comfort Specialist™ to help - America’s Most Trusted HVAC Brand.

Why does my A/C smell like feet?

ANSWER: You’ve probably got a mold and bacteria build up
Dirty sock syndrome is that moldy odor you get when you turn on your air conditioner for the first time of the season. It’s caused by mold and bacteria on your evaporator coil or other areas of your HVAC system. If the smell lingers after repeated use we recommend having your evaporator coil cleaned by a professional. Other steps you can take to remove musty odors include:

  • Check your filters
  • Check your ductwork
  • Clean the drain pan

Why is it hot upstairs and cold downstairs?

ANSWER: Your air conditioner can’t keep up. Create climate zones
The DIY way to do this is to close a few (not all) vents on the first floor. This forces your cooling system to direct more air upstairs. Take this concept to the next level by having an HVAC professional install a climate zone system, like the Trane ComfortLink™ II Zoning System. In this system, heated or cooled air is directed where it’s needed most. If the problem continues, you may not have the right size air conditioner for your home and should consider installing a new air conditioner or one of our ductless systems to cool a single room.

Why is the air flow so low?

ANSWER: Clean or replace your filters
Over time, dust and dirt will collect on the filter screen. There could also be a blockage in your air ducts. If this is the case, you’ll need your local Trane Comfort Specialist™ to inspect the ductwork.

Why is my utility bill so high?

ANSWER: Your system is running too much
If you have your thermostat set to a temperature drastically cooler than the outside air temperature, your system has to work harder to maintain that temperature. This can result in a higher than normal utility bill. Try adjusting your thermostat to a more moderate temperature.

ANSWER: Your air conditioner is not energy efficient
If your air conditioner is over 10 years old or has a SEER rating of 10 or less, you’re probably spending more than you should each month in energy costs. Today’s energy-efficient air conditioners have energy saving features that allow them to cool your home while running on less energy - which can save you money each month.

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