Why Is My AC Running Nonstop?

If your AC is running nonstop, it’s trying—and failing—to adequately cool your home. But why would that be?

The problem might be a broken or leaking AC component caused by five major issues—especially if it's only recently started running constantly and you've been diligent in keeping up with regular maintenance. Start by asking yourself:

• Has your AC been running nonstop since it was installed?
• Do you have a dirty AC?
• Do you have a broken AC component?

Let’s break down these possible causes and their solutions in the sections below.

If your AC doesn’t stop running, it won’t stop racking up your energy bill, either! For fast, same-day service, schedule your AC repair with Advanced Air. Schedule an appointment online or call (888) 853-5143 for emergency service.

If you recently had a new AC or thermostat installed, you probably have an issue with the size of your AC or your thermostat's settings.

Not all ACs can cool a large home. If your new AC is too small, it will be unable to reach your desired temperature and run nonstop to compensate.

Solution: An HVAC professional can help you determine the correct AC unit size for your home’s square footage.

If you recently installed a new thermostat or updated its settings, you may have inadvertently instructed your AC to run nonstop.

Solution: First, check to make sure your thermostat is set to “AUTO,” not “ON.” A thermostat in the “ON” position will force your AC to keep blowing air, even once the desired temperature has been reached.

If it’s already set to “AUTO,” then check to see what temperature your thermostat is set to. If it’s set extremely low compared to the outdoor temperature, your AC won’t be able to adequately cool your home no matter how long it runs.

If your AC recently started running nonstop, it might need to be cleaned or repaired, which we’ll cover next.

We’re not pointing any fingers here, but be honest … do you regularly clean and maintain your AC? If you’ve put off maintenance of your AC, then a dirty air filter or evaporator coil could be the reason your AC is running nonstop.

Your AC’s air filter collects dust and dirt from your home’s air before it enters your unit. The purpose of air filters is to keep AC components such as the evaporator coil (more on this below) clean.

A dirty air filter means it’s doing its job. However, once it becomes completely full of debris, it can’t draw as much air into your AC. Less hot air into your AC means less cool air out, so a dirty air filter can prevent your home from becoming adequately cooled, forcing your AC to run nonstop.

Solution: Professional HVAC technicians recommend changing your air filter every month during the cooling season.

1. Turn off your AC system before you take out your dirty air filter.
2. Check the filter’s label. All filters should have a label on their side giving you the size measurements. You can also check the system’s manual or just use a measuring tape.
3. Buy new filters. We have 1” to 5” filters and can custom order your filter size if needed.
4. Insert the new air filter into the insertion slots. You’ll want to make sure you insert the filter using the arrows on the side of the filter.

Your AC’s evaporator coil is also essential to your AC’s cooling function. It is filled with liquid refrigerant, which absorbs heat from your home’s air and releases it outdoors.

If the evaporator coil is covered with dirt or dust, then the refrigerant inside is limited in its capability to interact with your home’s air. This prevents it from removing heat and reduces the cooling capacity of your AC, which can cause it to run continuously to try to meet your cooling demands. The evaporator coil might even freeze without cleaning.

Solution: To make sure your AC stays clean, an HVAC technician should perform yearly maintenance on it. The benefits of enrolling in an annual maintenance plan include:

• Lengthens the lifespan of your AC
• Keeps it running efficiently
• Prevents small problems from becoming big ones
• Discounts on service repairs

Your AC may also be running nonstop because your blower motor is broken, your air ducts are leaking, or refrigerant is leaking from your AC system. If you suspect that you have one of these problems, it’s a good idea to call an HVAC technician for a professional opinion.

The blower motor is what pushes cooled air back into your home. If it’s broken, then even though your AC is cooling air, it won’t be released efficiently back into your home. Because your home won’t feel cool, your AC will run nonstop.

The blower motor pushes cool air into your home through air ducts. If your air ducts have leaks, air can escape through them instead of cooling your home. Without enough cool air blowing through your home, your AC will need to run more continuously.

Like we mentioned above, refrigerant is what absorbs the heat from your home’s air. Not enough refrigerant in the AC system will stop it from absorbing as much heat from the air, prolonging the cooling process and causing your AC to run continuously.

Whatever you do, don’t let an HVAC technician simply refill or “recharge” your refrigerant levels. Refrigerant is sealed in your AC system; if levels get low, there is a leak somewhere that needs repair. Refilling it without sealing the leak will only fix the problem temporarily.

All of these problems require help from a professional HVAC contractor.

The best way to keep your AC running smoothly (and keep your energy bills low!) is to schedule annual AC maintenance, ideally in the spring, before you start using your AC daily. Advanced Air makes it easy for you with our CoolClub plans—two options for scheduling AC maintenance with the added bonus of discounts and free emergency service. If you’re past the point of maintenance and need an AC repair ASAP, give us a call at (888) 853-5143. We promise to get your AC up and running within 24 hours, so you can feel comfortable in your home as soon as possible.