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Why Can’t My Air Conditioner Keep Up on Hot Days?

energy efficient insulation | home insulation

Why Can’t My Air Conditioner Keep Up on Hot Days? Blog Feature
Amanda Emery

By: Amanda Emery on July 1st, 2022

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In the past few years, we have seen record heat across the country, and many find their air conditioner can’t keep up on hot days.

An AC constantly running will cost you a lot of money – not only in high energy bills but in maintenance costs for your air conditioner. The cost is terrible, but if your AC runs all day on hot days, your house probably isn’t all that comfortable.

The quick answer here is that it isn’t normal that the AC won’t stop running. As a matter of fact, little to no insulation in your home is likely the culprit. There are several other possible reasons, as well.

Our network of RetroFoam dealers are on a mission to help homeowners make their homes more comfortable and energy-efficient. We all understand how important it is to keep your home cool in the summer while saving money on cooling costs.

Let’s dive into why your AC won’t stop running and how to fix it.


Why Your AC Can't Keep Up with Heat

There are several reasons your air conditioner can’t keep up on hot days, and some of those reasons may not seem very obvious to you.

The AC Unit is Too Small for Your Home

You can feel the cool air coming from your vents, but it’s just not enough to cool your house down.

This is because the air conditioning unit isn’t the right size for your home. The unit can pump that cold air to its little heart’s content, but it just isn’t going to cool your entire house down. If the unit is too small, it will constantly run in an attempt to maintain or even reach the temperature you have set the thermostat at.

If your air is continuously running, this will cause the cooling coil, also known as the evaporator coil, to freeze, according to Cool Today. When the coil freezes, it can lead to the liquid refrigerant flooding back into the unit’s compressor, damaging it.

The Location of the Thermostat

Did you know the location of your thermostat can dictate how long your AC unit runs?

Ideally, the thermostat should be in the middle of your home without vents blowing on or near it. If there are vents near the thermostat, that cold air will make the thermostat think it is cooler in your home than it actually is.

When the thermostat is registering cooler than it actually is, you’ll end up with rooms throughout the house that are much warmer than other areas. It’s also pretty likely that you’ll adjust the thermostat in order to cool those spaces down, and the cycle begins all over again.

The Air Conditioner Hasn't Had Regular Maintenance

If an air conditioner isn’t regularly maintained, it can drastically affect how it functions.

Ideally, the filter should be changed every three months or more frequently, depending on how often it runs. Without this regular maintenance, the AC unit will begin to have poor airflow or freezing up of the evaporator coil.

A dirty filter could add five to 15 percent to your monthly energy bill and significantly reduce the unit's lifespan, according to Time. The cost to replace a dirty filter is much cheaper than replacing the coil or the entire unit.

Airflow in Your Home Could be Restricted

Several different factors can cause restricted or reduced airflow from your unit.

The air conditioner could constantly be running because something prevents it from supplying the cool air you want. The blower in the unit may have gone bad, or something could be physically blocking it. 

These are some of the things you could be experiencing if the airflow is restricted.

  • The air coming from the vents is cool, but the airflow is weak.
  • The filter is dirty, causing the airflow to be restricted.
  • The ducts are closed or blocked.
  • The ductwork is improperly sized or damaged.
  • The evaporator coil in the unit is frozen.
  • The unit’s motor could be malfunctioning.

The Ductwork in Your Home Isn't Insulated

If the ductwork running through your home isn’t insulated, this could cause your AC unit to run constantly.

So, why does this happen?

Here’s the scenario. Your ductwork runs up through the attic, which is extremely hot. Now, all the air you are paying to cool is heating up as it moves through the ducts. By the time the air comes through the vents, it’s not cold anymore. 

There is Little to No Insulation in Your Home

If there is little to no insulation in your home, then all that hot air from outside is seeping through your walls. 

The real kicker is that even if you have fiberglass or cellulose insulation, those two materials will still allow air movement. Traditional insulation doesn’t have the ability to create an air seal or barrier to prevent hot air from outside entering your home. Your air conditioner is working overtime to combat this, which is costing you more money in cooling costs and repairs. 

So, what is the answer to giving your AC unit a break?

How to Prevent the AC Running 24/7

If you want to stop air movement into and out of your home, creating an air seal is vital, according to the U.S. Department of Energy.

RetroFoam insulation in your existing walls will create an air seal that will help your home maintain a constant temperature. This will help give your air conditioner a much-needed break, as well as your wallet since it won’t run all the time.

If you’d like to find a RetroFoam dealer in your area, check out our Dealer Finder on our website.

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About Amanda Emery

Amanda previously has worked as a breaking news and crime reporter, TV news producer, and editor. As a journalist, she has won several awards from The Society of Professional Journalists - Detroit Chapter and the Michigan Press Association. Amanda uses her experience as a journalist to write content that will help educate homeowners on foam insulation benefits. When Amanda isn’t writing, she’s spending time with her husband Chris, daughter Lilith-Maeve, and rescued huskies Danger and Wendigo. She also loves knitting, making art, and cooking.