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AC Repair & Installation

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.

A finger adjusting thermostat settings.

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.

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.