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AC Running But No Cold Air? Here's What Could Be Wrong.


When you turn on your AC, you expect relief from the summer heat. The last thing you want to experience is warm air blowing throughout your house! This not only adds to the discomfort caused by heat in your home, but it can also be dangerous if you or someone in your home is particularly sensitive to heat.

There are many different kinds of problems that can affect your air conditioner. Not all of them involve a total failure, either. Sometimes it can appear as if your air conditioning unit is running fine, but you’re not getting the cold air you need circulating in your home.

Fortunately, this problem doesn’t have to be a mystery. In fact, an AC not blowing cold air is one of the most common problems our expert HVAC techs at Bay Heating & Air Conditioning come across. Through our many years of experience, we’ve identified a few different causes for this problem. Read more below!

Dirty or Clogged AC Filter

If it seems like only a small amount of warm air is coming from your vents, this can indicate a problem with your AC’s filter. Its purpose is to prevent outside allergens and debris from getting inside, but once a filter becomes too dirty or clogged, it won’t do its job as effectively.

This can prevent your AC from moving enough temperature-treated air throughout your home, allowing what little air it can blow through your filter to warm up by the time it reaches your vents.

If this is the underlying problem, our HVAC techs can clean or replace your air filters. This service should be performed every three months or so to prevent future problems involving your air filter from occurring.

Dirty or Clogged Air Ducts

This problem is similar in nature to having a dirty AC filter, but it can be more extensive depending on the ductwork in your home.

When dirt and debris get past your AC’s filter, they can settle in your ductwork and accumulate over time. Eventually, enough debris can collect to actually restrict airflow in your home’s ductwork. If you have a rodent or avian pest problem, these critters may be responsible for causing blockages through their nest-making behavior.

Cleaning air ducts is a lot more involved than cleaning an AC filter. It’s best to contact an HVAC tech to assess the status of your air ducts and perform a thorough cleaning to remove any debris that may restrict cool airflow in your home.

Low or Leaking Refrigerant

Refrigerant is a substance that allows the heat transfer process that cools air to occur. When your AC doesn’t have enough refrigerant to cool outside air, it will blow that warm air throughout your home.

AC units can experience problems with refrigerant when there is a leak or if the device hasn’t been serviced in many years. Refrigerant leaks can be difficult for homeowners to detect because they can occur slowly over time and out of sight. For this reason, you should contact an HVAC tech to evaluate your AC system to determine if low or leaking refrigerant is the culprit.

Evaporator Coil or Condenser Problems

When problems involving components such as your AC’s evaporator coils or condenser occur, you can experience warm air flowing throughout your home.

Evaporator coils must be kept clean to do their job correctly, but they can be prone to accumulating mold and mildew that adversely affect their function. Also, problems with low refrigerant can also affect evaporator coils, causing them to freeze up and fail.

When your air conditioner’s condenser isn’t working properly, this is another issue that can affect the heat exchange that cools the air.

Thermostat Problems

Your home’s thermostat can also cause warm air to blow into your home. This is the “brain” of your HVAC system, so if it’s not sending the correct messages to your air conditioner, you will get much different results than you expect.

If your AC is blowing warm air and the problem lies with the thermostat, you might have it set to “heat” instead of “cool.” If this is the issue, your AC won’t know it needs to start the heat exchange process.

Beyond this simple mistake, your thermostat could have issues with its hardware or software that might be sending the wrong messages to your AC system. In this case, you should get professional assistance to help you correct this problem or rule it out as a possibility.

We Can Diagnose Your AC Problems!

When you’re experiencing any kind of issue with your home’s AC system, our team at Bay Heating & Air Conditioning can fix it. Our services begin with an assessment to determine the underlying cause of whatever problem is causing your AC to blow warm air in your home. Once we’ve figured it out, we’ll apply a long-lasting solution so you won’t have to experience the same problem again!

For more information about how Bay Heating & Air Conditioning can help, contact us online or call (440) 294-4954 to schedule an appointment.