Why Is My AC Not Blowing Cold Air? A Checklist for Homeowners

There’s nothing more worrying on a hot day than your AC not blowing cold air. We depend on that cold air to manage the heat and cut through the humidity. But, if your air conditioning unit isn’t up to the task, you may find that your indoor air is, well, a little too similar to the outdoor air.

When your air conditioner isn’t functioning properly, your initial instinct may be to reach for your phone. However, before calling, there are a few things you can investigate that may reveal the source of the hot air. Whether it’s a dirty evaporator coil, a clogged air filter, an improper thermostat setting, you may be able to diagnose the problem yourself.

Common Causes of AC Not Blowing Cold Air

If your AC unit is blowing warm air, there are a couple of simple issues that you may be able to diagnose yourself. While it’s recommended that you call a technician to address major issues, minor problems – and oversights – can often be corrected without help.

Of course, if you aren’t comfortable working your air conditioner, you should always reach out to a residential HVAC professional.

Incorrect Thermostat Settings

One of the first things you can check is whether your thermostat is set correctly. If you haven’t updated your winter settings yet, your thermostat may not be telling your AC system to turn on.

Dirty Air Filters or Clogged Filters

A blocked air filter can cause your air conditioning system to malfunction and blow warm air. Luckily, this is an extremely easy fix. Remove your filter, inspect it for debris, and replace it if necessary. In most cases, it’s recommended that you replace dirty filters every three months.

Leaking or Low Refrigerant

Unfortunately, refrigerant leaks are an issue that requires professional help. Difficult to diagnose without special tools, it’s best to call a pro if you suspect your refrigerant lines are damaged.

Ice Buildup on the Unit

During heatwaves, it’s not uncommon for air conditioning systems to become overworked, which can clog filters, damage evaporator coils, and cause ice to form. If you see ice on your system, turn it off until the ice is fully melted. Then, if it still refuses to blow cold air, call a professional.

Frozen Evaporator Coils

On the subject of ice, a failing evaporator coil can cause your AC unit to blow hot air. If you’ve already noticed ice on your unit, it’s likely an issue with the coil. But, malfunctions could also be caused by dirt, debris, or blockages that you’re able to clear yourself with a soft bristled brush.

Dirty Air Compressor

If all else fails, your air conditioner may have a dirty AC compressor. Caused by a buildup of debris, it can limit the unit’s ability to transfer heat and create cool air. Sadly, this is an issue best fixed by an AC technician with the tools necessary to do the job properly.

How to Fix an Air Conditioner Not Blowing Cold Air

If your air conditioning system is blowing warm air, it may not be too difficult to get it working properly. Assuming it’s a minor fix, you can probably even make a couple of small adjustments and hopefully won’t need a new air conditioner.

Reboot Your Thermostat

First things first, if you know that your thermostat settings are correct, you may need to do a quick reboot to get them to work properly. If you’re not sure how to reboot your thermostat, you can easily power it off and then back on by flipping the circuit breaker that controls your HVAC system.

Change Out Dirty Filters

It’s important to change your system’s air filters on a regular basis. If it’s been too long since your last filter change, it can cause your AC unit to malfunction, which can result in uneven temperatures. Luckily, it’s extremely easy to change air filters on most HVAC systems.

Clean Your Condenser Coil

If your condenser unit has become clogged with leaves, sticks, or other debris, you’ll need to clean it to restore full functionality to your HVAC unit. First, ensure that you’ve turned your system off. Once it’s off, use diluted soap and hose to gently rinse the unit and dislodge any debris.

Defrost Your Evaporator Coil

When ice builds up on your evaporator coils, it can restrict airflow and result in your AC not blowing cold air. To remove the ice, simply turn your AC unit off, allow the ice to melt, and then restart the system.

Other Air Conditioning Issues

For other, more complex issues with your AC or central air system, you’ll likely need to consult with a professional. Larger issues can be things like refrigerant leaks, compressor failure, and air duct leaks. In some cases, a new AC system may be necessary. However, the team at R.W. LaPine will always work with you to find solutions that are in your budget.

Want the Opinion of a Professional HVAC Technician?

At R.W. LaPine, we have the tools, knowledge, and experience necessary to address all issues with AC systems. Whether you have a refrigerant leak, poor air quality, or warm air blowing from your unit, we can help.

So, if you’ve noticed your system isn’t blowing cool air, we encourage you to reach out to us today. With experience working on a wide range of HVAC systems, we’ll walk you through your issues, discuss your options, and get your cooling system back in action.