Homeowner Help: When an AC Stops Blowing Cold Air

There is never a worse time for your AC to quit working than in the middle of a hot Illinois summer. It might even sound like your air conditioner is working, but you find that it is doing something very wrong. One problem that can happen is when an air conditioner starts blowing hot air.

If you find your AC is not blowing out cold or cool air anymore, you will need to act quickly as your house is surely heating up. But there is some good news. This situation doesn’t always mean your cooling system is completely broken. And not only that, there may be some DIY troubleshooting work you can do yourself to fix the problem!

When to Call for Professional AC Repair

While you can go right to the phone and call a licensed air conditioning professional like our team at Maximum Heating & Air, there are several reasons not to do that right away. Instead, by taking a bit of time, you can possibly find the source of the AC problem and resolve it yourself.

We receive calls all the time from people across Aurora quite upset to find out their heating and cooling system has broken down. We handle all sorts of air conditioning repair work. Sometimes when we show up to fix their AC, we discover that the problem was minor enough that the homeowner may have been able to fix it themselves. While we appreciate you trusting us with your home’s AC service, we are also happy to provide you with the information to help you handle minor issues on your own, when possible.

After all, why spend money when you can fix it yourself?

AC Blowing Hot Air: 4 Steps to DIY

There are 4 basic steps you can attempt to address the problem yourself. Each DIY repair step takes little to hardly any skill. They can be done by just about any homeowner at any level of handyman skill. Not only that, these DIY repair steps can be done with little or no money!

Graphic showing the 4 DIY steps to help fix an air conditioner blowing hot air


First we are going to address what may be the easiest problem to fix. Sometimes getting your cooling system to blow out cool air again is as simple as pushing a button. Is there anyone in your home who messes with the thermostat? It’s possible a setting may be off. Simply putting your thermostat where it should be could put a stop to that hot air.

  • Make sure your thermostat is set on COOL, and that it’s not only on FAN or HEAT.
  • Set the thermostat to be lower than current temperature.  Have you adjusted the temperature since summer started? If not, your thermostat may actually be set to a higher number than the ambient temperature. This is more likely the case if you’re discovering the problem at the beginning of the summer season. You may simply need to lower the desired temperature to be below the current air temperature in your house. Rather quickly, you could hear your air conditioner fan from your indoor system kick on. And shortly after that, you can expect to feel the cool air coming.


  • Check the vents throughout your home. Are they all open? Some people believe that they should close vents in the rooms that don’t need as much heating and/or cooling. That can actually cause problems. While it is okay to close a couple of vents, having too many closed could negatively affect the air flow your home’s HVAC system needs to effectively do its job.
  • Feel to make sure air is coming out of the vents. If you can’t feel anything, your cooling system’s fan motor may not be working. If that’s the case, call Maximum Heating & Air at (630) 788-4688 for a quick repair.


The HVAC system in a home is often found in the basement. It typically consists of a furnace as well as a portion of the air conditioning system called an evaporator. This evaporator takes in the heat from your home’s air and transfers it air to your outdoor AC unit (the condenser).

While the indoor component of your HVAC system stores the fan that blows the air through your home, it will do this whether or not your outside unit is working. It’s your outside unit that creates the cool air that indoor fan needs to circulate in your home.

A clean air filter next to a dark and dirty air filter that could keep your AC from blowing cold air
  • Check your air filter. If it looks dirty or clogged or you can’t see through it anymore, it’s definitely time to change it. Some AC units have a built-in mechanism that will shut the system down if the filter is clogged. This could be the only work needed to your AC blowing out cool air again.


You’re going to be checking to see if it’s either frozen over or simply too dirty to work properly.

  • Go outside and look at your outside AC unit. Do you see any frost or ice on it even though the weather is too warm for that? If so, change the setting on your thermostat from COOL to FAN ONLY. You may need to have the fan run for as much as 12 hours to get your unit thawed out.
  • If you skipped Step #3, check your air filter now. A frozen outdoor AC unit can be a sign that your filter is very dirty and needs to be changed.
  • If the coils on your outdoor condenser unit are dirty or covered with leaves, dirt or other debris, you should clean them. If this gets your AC to stop blowing hot air, but only temporarily and you see frost or ice develop again later, you might have a freon leak. call Maximum Heating & Air at (630) 788-4688 to handle a potential freon leak quickly and safely.

Cleaning a Dirty AC Condenser: Turn off your condenser unit, remove the top section and any outer caging. Dust around the entire unit with a brush to get rid of any dust, dirt, or other material. Using a hose, spray the coils from the inside of the condenser pointing the hose out.

Various issues that could cause a broken ac that require professional air conditioning technician

Power Check

If your AC is not blowing ANY air at all, then check your home’s power. Did you have an outage? You should make sure you didn’t blow a fuse or have some other house-wide issue happening. When in doubt, give us a call at (630) 788-4688 and we can fix whatever is causing the problem, even if that means resetting your breaker box.

Have questions? Just ask Aurora’s Air Conditioning Experts!

Maximum Heating and Air has worked on thousands of heating and cooling systems across the Aurora, Il area. Our skilled air conditioning technicians have many years of experience fixing furnaces and repairing broken ac units. We have seen all types of HVAC problems, big and small, and can fix whatever problem you are having, no matter what type of HVAC system you have. Call Maximum Heating & Air for immediate service at (630) 788-4688 or request a free estimate online.

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