Understanding Why Your Air Conditioner Won’t Shut Off and Resolving the Issue

Summer’s over and now it seems like your air conditioner isn’t shutting off! What gives? The thermostat says that the temperature is set, but the air conditioner just won’t seem to turn off. Don’t worry, there are plenty of reasons this could be happening, and we’ll cover the most common causes of your air conditioner not shutting off along with how to fix them!

Before you get to work trying to solve your AC problem, check its thermostat setting. It might be running too high for no reason. Set it to a lower temperature and see if that fixes your issue. Inspect your air conditioner vents and parts to make sure they aren’t dirty before contacting a professional to perform a full inspection. Remember, regular maintenance is key when keeping your AC in top shape!

We’ve put together an overview of some of the most common problems with air conditioning units, as well as their solutions. This way, if your air conditioner isn’t shutting off correctly, we can help guide you to a solution!

Is It Acceptable for an Air Conditioner to Never Shut Off?

You may be wondering why your air conditioner won’t shut off. There are a few reasons this might happen, but don’t worry – there are fixes! Air conditioners are nice to have running during the hot summer months, but that doesn’t mean it should be constantly running.

You should be able to turn it off when it’s no longer needed. Leaving an air conditioner running will reduce the life expectancy of your unit and increase your utility expenses. Let’s dig into some of the reasons it may not be shutting off.

Why Your Air Conditioning Unit Will Not Shut Off, & Solutions For Each Problem

If your air conditioner unit is not shutting off, there are many possible reasons for the issue. Common issues can be due to

  • Wrong sized air conditioner
  • Fan set to on
  • Hot weather
  • Thermostat issues
  • Dirty parts
  • Broken parts

New Air Conditioner is Too Small for Its Location

There are a few different reasons why it’s not shutting off and one of them could be because the air conditioner is too small for its location. It’s important to get an air conditioner that’s appropriately sized for the location.

If possible replace it with something bigger that can handle your air conditioner demand. It’ll help both with the strain on your unit as well as the overall efficiency of your home.

Air Conditioner Fan is set to ON not AUTO

It’s an easy mistake to make, and it can be a problem if you don’t fix it. In the summer months, we want our air conditioners to shut off when we leave the house or when we go to bed. But what happens if your fan setting isn’t set to auto?

The problem with leaving the fan set to on instead of auto is that it will continue running even after you turn off your air conditioner. The fix is easy, simply go to your thermostat and adjust your fan setting to auto. This will turn off the fan when the A/C has been turned off.

Hot Weather

In hot weather, your air conditioner keeps working to keep your home cool. With high temperatures and humidity, keeping your air conditioner from running all the time can be a challenge.

In the summer months, homes with central AC systems may need to run their ACs for most of the day in order to maintain comfort. Unfortunately, there isn’t a fix for hot weather, but it helps to understand why your air conditioner kicks on in the first place.

Thermostat Issues

The thermostat is a crucial component to your air conditioning system and without it, the AC won’t turn on or off. Sometimes it as simple as fixing a setting on the thermostat. Other times it’ll require a replacement.

Thermostat is Improperly Set

If you live in a warm climate, there is a good chance that your AC is constantly running to keep you cool. However, this might not be necessary and it could be costing you money!

Incorrectly setting your thermostat can cause your air conditioner to constantly run when it doesn’t need to. With thermostats the lower the temperature set on the thermostat, the more likely the air conditioner will come on when it’s hot outside. If you have set your temperature too low on the thermostat-your air conditioner will be working overtime without reason which wastes electricity and causes costly utility bills!

Thermostat is Damaged or Broken

When your air conditioner is shutting off and not turning back on when it should, this is a problem. A broken thermostat will affect your ability to communicate with your air conditioner. Without the right input, your AC may be doing damage by running without turning off. You can fix the issue by installing a new or replacement thermostat! 

There are plenty of options available these days from being able to set schedules to controlling it from your phone, a new thermostat could make all the difference for you.

Dirty Air Conditioner Part

Homeowners often complain that their air conditioner won’t shut off even after the thermostat has been turned off. This can be caused by a dirty part like a filter, which will accumulate dust and other allergens over time. Dirt will cause damage to your HVAC system and possibly requiring a replacement sooner than you’d like.

Common areas to inspect for excessive dirt include

  • Air Filters
  • Condenser Unit
  • Condenser Coils
  • Evaporator Coils

Air Filter

If your air conditioner is suddenly not turning off or even freezing, it is possible that the filter needs to be replaced. This problem can stem from a clogged or dirty filter. The easiest way to fix this problem is by replacing the filter.

A dirty filter could be causing your air conditioner to run indefinitely. This problem can sometimes cause short circuits or electrical issues because of excess heat that builds up inside of your AC unit.

Condenser Unit

You have a problem with your air conditioning. Why? Maybe the condenser unit is not shutting off when it should. This can lead to higher electric bills and inefficient cooling.

A condenser unit is supposed to turn on as soon as the outside temperature reaches a certain threshold and turn off at another specific temperature. When this isn’t happening, one reason might be because your thermostat is set too low for it to reach its off temperature and another might be because your refrigerant pressure isn’t high enough, or maybe the condenser unit is too dirty.

A dirty condenser unit will create more problems, so check to make sure the fins are clean of dirt or anything that could block airflow. If a condenser unit gets to the point where it needs to be replaced, you’ll likely need to seek help from the professionals when it comes to replacements.

Condenser Coils

Condenser coils can be a major problem for air conditioners. Dirty condenser coils can cause your air conditioner to not shut off, or even worse – shut off and then come back on again. This is a serious issue that must be addressed as soon as possible.

Dirty condenser coils will eventually need to be cleaned by a professional. If you are unable to have this done by someone else in the near future, make sure you schedule an appointment with your AC technician before it becomes too late!  Which could lead to many other costly problems

Evaporator Coils

An evaporator coil is the device that cools air by running it over a surface that has been cooled below the ambient temperature. The refrigerant flows through the coils, absorbing heat from the surrounding air and discharging it to the outside of the system. Evaporator coils are typically located inside the air handler or furnace.

Some homeowners report that their air conditioning units are shutting off and they don’t know why. There’s a chance the problem is dirty evaporator coils. The coils can accumulate a layer of dirt and grime over time, which may disrupt the airflow through them. If this is the case, you need to clean them!

It is equally effective to use a mild detergent and water in a spray bottle or garden sprayer to clean the coils as a cleaner. Give the solution a few minutes to soak in and loosen the dirt and debris on your evaporator coils.

The coils of your air conditioning system sit inside a metal box, which sits outside your home. The coils cool down refrigerant and distribute it to your indoor air conditioners, helping them to lower the temperature of your home’s indoor environment.

Freezing evaporator coils can be a problem for your air conditioning unit because it will keep your air conditioner from shutting off. The coils get iced over and the ice prevents the coolant from escaping to the outside of the coil to create cold air.

If you can hear your air conditioner running and it just won’t turn off, then it could be because of frozen evaporator coils. In fact, that problem often occurs during humid weather when there is already condensation in your air conditioning unit. This isn’t always a permanent problem and can correct itself after a while. All you need to do is wait for an extended period of hot weather and moisture to clear out of your coils.

If you aren’t able to wait for the weather to accommodate, you may need to call an HVAC technician. They will use an anti-freeze solution to help with the process of removing all the ice from your evaporator coils.

Broken Air Conditioner Part

If your air conditioner isn’t shutting off, it could be due to a broken air conditioner part. Broken parts can prevent your unit from starting or stopping. There are certain parts that commonly cause the problem like leaky air ducts or refrigerant levels.

Leaky Air Ducts

If you notice your air conditioner is running for a long time and it’s not cooling the house like usual, it might be because of a leaky air duct. Leaky air ducts will cause more energy to be used to cool an area which can result in high bills. The best way to fix this problem is by sealing any cracks or holes in the line that could cause an unwanted flow of warm air into your system.

Leaky or Low Refrigerant

Having a leaky or low refrigerant is a major problem because the air conditioner won’t turn off, which is exhausting for the machine and not good for you either. The fix is to have it recharged with refrigerant.

If you have a leaky or low refrigerant, you’ll need to take care of it as soon as possible. The problem will only get worse if it isn’t fixed right away because your air conditioner won’t cool off properly and it could break down. You’ll also notice problems with humidity and moisture inside your home.

Electrical Issues

If you are having trouble getting your air conditioner to turn off, check to see if the thermostat needs to be adjusted. If you can’t control the air conditioner’s ability to turn on or off you may have potential electrical issues. There are a number of possible electrical problems, but the two most common are a short circuit and the relay switch.

A Short Circuit

One of the most common reasons your air conditioner is not shutting off is because of an electrical issue. This could be a short circuit, or it could be as simple as an unplugged wire. Make sure that you check all your electrical connections and make any needed repairs.

If you don’t have any electrical experience, it may be best to call a professional to assess the potential problem and make necessary changes. The last thing you’d want is to get shocked while inspecting your wiring.

The Relay Switch

The relay switch is responsible for shutting off the system when it has cooled to a certain temperature, but if it is broken or misaligned then this cannot happen. If your air conditioner isn’t turning on and off at all then this might be what’s going on with it. If you are having trouble figuring out how to fix your AC not turning on, contact a professional technician today. Don’t casually mess with any electrical components of your air conditioning unit. Safety should always be a priority.

How To Prevent Air Conditioner Problems

The best way to keep your air conditioners running smoothly all summer long is to take preventative care. The most important preventative care you should be doing for your air conditioners are the following:

  • Change the filters regularly
  • Keep it clean outside your vents and unit
  • Get regular check-ups
  • Keep an eye out for unexpected spikes in utility bills

Taking preventative measures can help extend the life of your AC, making this a wise investment!


If you notice that your air conditioner isn’t shutting off, don’t panic! There are a few different things that can be the problem. With a little research and some DIY skills, you should have your air conditioner back up and running in no time. Issues commonly come from thermostat settings, dirty or broken parts, or electrical issues. Fortunately, a lot of these can be taken care of by the homeowner, but don’t be afraid to call in the pros for anything you’re unfamiliar with.

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