AC Not Cooling? 7 Things To Check When your air conditioner is not cooling the house

Is your AC not cooling your home? We know how difficult this can be and we're here to help. This is especially true when dealing with the extreme heat of Central Florida. In this article we are going to help you understand why your air conditioner is not cooling the house and more importantly what you can do to fix your air conditioner.

But first, let's address the specific problem this article is tackling.

In this article we are specifically addressing what to do if you air conditioner is running but not cooling the house. It's fairly obvious that you need to find an air conditioning company when your AC is NOT running. But what do you do when your AC is running but not cooling? 

Put The Problem In Perspective

There are two questions you should ask yourself when you notice your AC unit running but not cooling. First, you need to ask yourself "How long has this been going on?". Secondly, "What is the temperature outside?".

Most people don't realize that air conditioners are meant to be "fine-tuned" for your specific location. In Orange County and Seminole County, we only surpass 93 degrees 1% of the year (based on a 30 year average). That means that a "fine-tuned" air conditioning system will operate normally as long as the temperature is below 93 degrees. However, once the outside temperature exceeds 93 degrees, you will notice your ac not cooling enough even though it's running.

ac not cooling

Chart of average temperatures in Orlando, FL. Courtesy of

While this can be frustrating on those 1% of extremely hot days, the payoff is that your fine-tuned air conditioner will do its job properly the other 99% of the year.

So before you spend too much time and energy trying to solve a problem, make sure it's truly a problem. Ask yourself if the temperature is above 93 degrees (if you are in Orlando) and is this an ongoing issue? If not, wait it out and more than likely you'll be comfortable again in no time.

If the temperature is not over 93 degrees and it is not an ongoing problem, then naturally you'll want to know why your AC is running, but not cooling the house. So that is what we'll address next.

Why Is my Air Conditioner Not Cooling My House?

If you find your AC not cooling your house, then you'll want to find the solution as soon as possible. So we will start by looking at the easiest solutions first. 

Check Your Thermostat

If your AC is running but not cooling, then check your thermostat settings. It's possible that someone changed the temperature or fan settings on the thermostat. Make sure it is set to "cool" and not to "fan". If the settings all look correct and you're continuing to have problems, then you should proceed to the next step.

ac not cooling because of thermostat settings

If you have a Nexia thermostat, you can connect your local service company to the thermostat so they have access to some internal diagnostics. Contact Pro-Tech to find out if your thermostat is connected and if we have access to any diagnostic information.

Change Your Air Filter

Your AC may not be cooling due to a clogged or dirty air filter. Locate your air filter and visually inspect it. If you notice it has a decent amount of dirt or debris, then change your air filter.

A standard 1 inch air filter should be changed about once every month. Changing the air filter not only gives you cleaner air, but it also ensures the proper air flow in your AC system. If the air filter becomes clogged it may be the reason your AC is not cooling your home.

If the air filter appears to be clean or your air conditioner is still not cooling your home after changing the air filter, then move on to the next step.

Air Filter

Check For Clogged Coils

A central air conditioning system consists of an indoor air handler and an outdoor condenser. Both pieces of equipment need regular maintenance. They both also have coils that are pivotal to how well they cool your home.

The outdoor condenser has coils that help release heat from the unit. However, if the outdoor coils become clogged they will not be able to release heat effectively. Ultimately, this means more warm air in your home.

Checking the outdoor coils is fairly simply. Just go outside and visually inspect the condenser. Are there shrubs or other debris located too close to the unit? Do the coils appear to be clogged with grass clippings, dirt or other yard debris?

If so, spend a few minutes gently washing the outside of the unit with a hose.

Pro-Tech offers a Comfort Club preventative maintenance plan to help our customers keep their air conditioning equipment clean. Our technicians will clean your outdoor condenser as well as the indoor air handler during each preventative maintenance.

man cleaning the condenser coil

The indoor air handler also has evaporator coils that remove heat from the air. The indoor coils can become dirty and clogged if you do not change your air filter on a regular basis. We do not recommend that you attempt to clean the indoor coils as they are more delicate than outdoor coils. 

If you suspect that your indoor coils are dirty, it's best that you contact a professional AC company to clean your indoor coils.

Frozen Evaporator Coil

Another problem that can cause your air conditioner to run but not cool is a frozen evaporator coil. We have an article on how to fix a frozen ac line. But in short, turn your air conditioner off if you have a frozen AC. Allow your system to run on "fan" only until the coil is no longer frozen. In the meantime, follow our tips for fixing a frozen AC.

picture of frozen ac line

Leaking Refrigerant

Refrigerant is the fluid inside the copper coils in your air conditioning system. Refrigerant is responsible for absorbing heat from the air in the evaporator coil. Each system must be filled with a precise amount of refrigerant to work properly. If your refrigerant leaks out, it will negatively impact your systems ability to cool the air.

It's important to note that if your refrigerant is leaking, then you should focus on repairing the leak rather than simply adding more refrigerant. Fixing problems with refrigerant leaks is an air conditioning repair that a trained HVAC technician should perform.

refrigerant leak

Repair Leaking Ductwork

If the ductwork in your home is old, there is a chance that a leak has developed in the air duct. Leaky duct could be the reason for your air conditioner not cooling even though it's running. A properly sealed ductwork system is important to make sure your cool air is not leaking into your attic space.

If you suspect that your ductwork is leaking, you can request an air duct assessment from Pro-Tech to receive a full inspection as well as an estimate for replacing any torn ducts.

new air duct

Replace An Undersized Or Aging AC System

Your HVAC contractor who installed your AC equipment should ensure they install a properly sized system for your home. If you have an undersized unit, then it is likely that you will regularly experience problems with your AC unit running but not cooling your home. If this is caused by a system that is undersized, unfortunately the only solution is to replace it with a properly sized unit.

On the other hand, your air conditioner may be properly sized, but due to its age or a lack of maintenance, it's no longer able to cool your home as well as it once did. If this is the reason that your air conditioner is not able to keep up with the heat, then a new air conditioner (properly sized) should solve the problem for you.

Air Conditioner Not Cooling Still?

If you have done what you can, but you still need helping fixing an air conditioner not cooling, then we invite you to contact Pro-Tech for your air conditioning service. We have served Central Florida since 1961 and we service all makes and models of equipment. 

If you want to ensure that your AC continues to run efficiently for years to come, we also invite you to sign up for our preventative maintenance program.

Contact us today to get immediate help fixing your air conditioner.

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