When Your Air Conditioner Blows Hot Air

What to Do When Your A/C Isn’t Blowing Cool Air

Imagine turning on your A/C and feeling warm air blowing back at you. It’s a sure bet that this will be an unfortunate reality for some Denver area homeowners this summer. An air conditioner blowing hot air instead of cold happens when any number of different problems are occurring somewhere along your HVAC system.

Discovering this problem with your air conditioner right in the middle of a Denver heat wave can seem like a massive problem. Fortunately, while this is a problem, it might not be as serious as you may think.

An A/C blowing warm air does not always mean your air conditioner is broken

Once you feel hot air is coming out of your vents, you may think the best thing to do is to call for a professional AC repair. While that is definitely an option, and one of our skilled technicians at DALCO Heating & Air Conditioning would be happy to rush out and fix your A/C no matter where you are in the Denver metro, you do have a few other options.

Sometimes a relatively minor issue could be causing your air conditioner to blow out warm or hot air. These minor issues can often be solved easily by the homeowners themselves. You may be able to avoid spending money on having a professional technician come out and service the problem.

It may seem odd that an air conditioner company is recommending that you don’t call us for work, but our main goal is for you to have a working heating and cooling system. Often our technicians are called out to fix an A/C problem that turns out to require little work – a switch that was off or a setting that was wrong. There are plenty of fixes that homeowners can have handled themselves. Of course, identifying the problem is not always easy for a homeowner to determine. That’s what this helpful article can help you do!

We are happy to provide you with a list of easy problems you can check for yourself. Each step is relatively quick to perform. You may find one of them will completely resolve your problem and you have cool air coming out of your air conditioner again in minutes!

Before calling a professional air conditioner technician, first run through these 4 basic air conditioner checks.

4 Things to Check when Your Air Conditioner Blows Hot Air

Graphic image showing the 4 things a homeowner should check when their A/C is blowing hot air, simple troubleshooting fixes to a broken air conditioner


Getting your air conditioner to start blowing cool air again could be as easy as pushing a button. It’s possible someone simply changed the thermostat, whether it was intentional or by accident. A wrong thermostat setting could be all that is causing your air conditioner to stop blowing cool air.

Here is what to check for:

The thermostat should be set to COOL

No matter what number you set your thermostat at, if it is not in the COOL setting, your air conditioner can’t deliver cool air. Make sure the thermostat is set to COOL (versus being only on FAN or HEAT).

The thermostat should be set to a temperature colder than the current temperature

Is it set to a higher temperature than the ambient temperature? If so, just lower it to a temperature that is well below that. You should know right away if this fixes your problem. You will quickly hear your air A/C fan turn on and then feel cool air coming from your vents.

Check if the thermostat’s battery is dead

The thermostat requires battery power to work. Your A/C may not be working correctly simply because the thermostat can’t tell your HVAC system to lower the temperature. Try replacing the batteries in your thermostat to see if this fixes your air conditioner problem.


This is as simple as it sounds. Go room to room and see if your vents are open. And if they are not, open them. For effective heating and cooling throughout your home, most of the vents need to be open. We know many people believe shutting vents helps with temperature control or saving energy. This is a common misconception. Your HVAC system was designed to work best when the vents are open. This helps ensure proper air flow throughout your home. Do you feel any air coming out of your vents? If not, the fan motor may not be functioning. Contact us at Dalco Heating & Air Conditioning and we’ll send out one of our air conditioner technicians to get that fixed as quickly as possible.


Your home’s air conditioner system includes a component inside your home called an evaporator. It works by absorbing heat from the air and transferring it to your outdoor unit (the condenser).

You will be checking a few things here.

First, listen for the sound of the blower motor running. If it is not working, contact a professional air conditioning technician. A few different things could keep a motor from working, from lack of lubrication to electrical issues. These are best left to be handled by a HVAC professional.

Then you will want to see if there is any ice on the evaporator coil as that could mean there is a refrigerant leak.

While you are checking this indoor unit, also pull out your air filter. Is it dirty? You may be surprised to find that your air filter simply needs to be changed. A dirty filter can even cause problems like an air conditioner blowing hot air. Changing your filter on a regular and frequent basis is vital for your heating and cooling system to operate well. It’s possible you aren’t changing it as often as you need to be.

Fortunately, this is an easy problem to fix. Simply changing out a dirty, clogged filter to a clean one may solve your problem and get the cool air started again!

A new outdoor air conditioner condenser unit installed by Dalco Heating & Air Conditioning in Denver


Go outside to examine the condenser unit. You will want to make sure it is not covered in ice or frost. This can be caused by a dirty air filter, so if you did not change your air filter as listed in the last step, you definitely should. To get rid of the ice and frost turn your thermostat away from COOL so that only the FAN is on. It may take as long as 12 hours for your A/C unit to thaw.

If you had ice on your A/C unit and changing your air filter fixes the problem, but it’s only a temporary fix, your air conditioner may have a freon leak. Contact Dalco Heating & Air Conditioning and our technicians will come out to safely handle any dangerous leak.

You also need to check and see if your outdoor A/C unit is dirty. If your condenser is covered with milkweed, leaves or other natural debris, that may be causing it to not work properly.

How to Clean Your Condenser

  • Turn the unit off.
  • Remove the top section and outer caging.
  • Spray the coils with a garden hose. You need to spray only from the inside going out.

Dalco Heating & Air provides condenser unit cleaning as part of the A/C maintenance service we offer. Request service with us online or by calling 303-979-7541.

Other Broken Air Conditioner Problems

Did none of those 4 steps get your A/C blowing cool air again? Then it is definitely time to give us a call. Dalco Heating & Air Conditioning is available for 24/7 emergency repair service throughout the Denver metro area.

There are a variety of other (more complicated) problems that can keep an air conditioner from working properly. Our team of HVAC technicians have handled every type of air conditioner breakdown. You can be sure we will locate the problem and get it fixed.

Graphic image showing the variety of broken ac problems you should call a professional HVAC professional to fix, like Dalco Heating & Air Conditioning in Denver

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