5 Reasons Your AC Is Blowing Warm Air

5 Reasons Your AC Is Blowing Warm Air

There’s no reason to face discomfort in the summer months. Living and working in environments that are hot and humid can be uncomfortable and leave you a sweaty mess. A fan can help keep air moving around your home but it can’t make the air colder than it already is.

There’s no reason to sit around in the heat of the summer when you can turn on your air conditioner. Excessive heat and humidity in a home can cause damage to books, hardwood floors or even electronics. But it can be a real disappointment to turn on your air conditioning and hot air starts blowing out.

There could be many different causes for your air conditioner to not work correctly. Contacting a maintenance contractor is always a good idea. Below you will find 5 possible reasons to find a solution to the hot air that is keeping your house warmer than you’d like.

1. Wrong Thermostat Setting

Before you call for an air conditioning repair be certain to check that your thermostat is set correctly. It may surprise you that the thermostat has been switched to the heat setting. A curious child or a simple mistake can be the cause of this happening.

Depending on what kind of thermostat you own, there is also potential that your air conditioner is blowing hot air because it is programmable. If the programming settings call for a varying temperature or it has been incorrectly programmed.

Another possibility for hot air blowing is that your thermostat is set to “ON” instead of “AUTO.” When a unit is set to “ON” the fan will blow continuously, even when air isn’t being cooled. When you switch to AUTO the only time the fan will blow air into your home is when the thermostat calls for a change in air temperature.

You may also want to double-check that your thermostat is properly wired or has the needed batteries. If the thermostat isn’t getting any power you won’t be able to get cool air into your home and you will become uncomfortable.  Don’t call for a repair until you’ve checked your thermostat carefully.

2. Your Unit is Dirty

When an air conditioning unit is located outdoors there is potential for it to become so dirty it can’t get a steady stream of the air it needs. Poor airflow can be the cause of hot air blowing from your air conditioning instead of the refreshing cool air you expect.

Leaves, grass, and general debris can be sucked on to the grate of an air conditioner unit. Over time the leaves will begin to decay which can negatively affect the integrity of the metal on your AC. Debris can also harbor excessive moisture which could rust several components of an air conditioner.

An air conditioner works best when it is thoroughly cleaned. You can hire a professional to come and clean your air conditioner for you. It is also relatively easy to clean an air conditioner yourself. Taking a regular garden hose and using the spray to gently help the debris down and off the air conditioner will help the air blow cooly again.

Keep foliage from growing too close to your air conditioner to prevent build up. Sweeping out the inside at the beginning and end of the summer can also help your air conditioning run better and stop blowing hot air. It is recommended to have your air conditioning unit inspected yearly to avoid any hot air heating your home when it shouldn’t.

3. Evaporator Coil is Dirty


If you’ve checked your air conditioner for debris outdoors and you are certain your thermostat is set correctly, you could be perplexed. One of the most common issues for air conditioners blowing hot air is a dirty evaporator coil.

Check your air filter. You can check your glasfloss air filters and replace it every six months to help keep your HVAC unit running as smooth as possible. If you realize that changing your air filter has slipped your mind and your current filter is quite dirty, it is likely your evaporator coil is dirty as well.

The evaporator coils are so important to a well-working air conditioner. The coils take on the heat from your home’s air, leaving only the cold air you’re hoping for. When the coils are dirty the refrigerant within has a harder time removing the heat from the air.

When an evaporator coil gets dirty, it is best to let a professional clean them off. The service cost for coil cleaning varies based on the make and model of your air conditioner. There are many tutorials on how to clean the evaporator coils yourself but hiring a trusted professional is the way to go.

You can avoid dirty coils by setting calendar reminders to change your air filter regularly. In the case of air conditioner parts like evaporator coils, a good offensive plan, like replacing an air filter,  is better than having hot air blowing out in the heat of the summer. Air conditioner maintenance is just like car maintenance, something you want to stay on top of to avoid costly repairs.

4. A Tripped Breaker

Most air conditioner units have two breaker points, an indoor and an outdoor one. It is possible for the outdoor breaker to trip and the inside breaker to stay on. This will allow the air to keep flowing, it just won’t be cold.

A tripped breaker is a fairly easy solution, simply check your breaker box. If one is at the neutral point then flip it back on. Your air conditioning should return to working as normal. If the breaker trips again soon, do not turn it back on. Doing so could catastrophically damage your air conditioner. Call a certified professional for help if this is the case.

5. The Refrigerant is Low

Since air conditioning units cool your home’s air by removing the heat from the inside air and expelling the heat outside there needs to be a process to complete this step. Air conditioners do this through a liquid called refrigerant.

Heat is absorbed by the refrigerant in the evaporator coils and is then carried outdoors. If your AC unit is running low on refrigerant, your air conditioner won’t be able to transfer the heat out of your home at the levels you expect in the heat of the summer. Especially on hot days, the low refrigerant may not help the heat leave the air making it seem like only hot air is blowing.

You can first check to see if perhaps your refrigerant line is frozen. Frozen lines won’t work correctly. It will be easy to see when you look at your outside unit if the line is frozen. You want your refrigerant to be a liquid, not solid.

Since refrigerant is liquid, the only way it can get low is if your unit has sprung a leak. If you are pretty certain the refrigerant is the cause of your air conditioning problems call a professional to help repair the leak and refill the liquid.



If you find your air conditioner blowing hot air instead of the cold air you’ve come to expect, these five reasons may help you solve the problem. Since air conditioners are complex units and there are many different models and types of air conditioners on the market there could be more complex issues that are causing your air conditioner to not work correctly.

If you have ruled out these five issues and have done the best troubleshooting you are capable of, you will want to call the professionals you trust with the care of your air conditioner. Getting quality repair will have your home feeling comfortable for a long time. Your comfort is of the utmost importance so don’t hesitate to take good care of your air conditioner.