Summers in Raleigh, North Carolina, can be unbelievably hot. During the hottest part of summer, warm weather begins at around 8 a.m., and it will continue well on into the evening. You may turn on your air conditioner as the sun starts to rise and keep it running into the night. How many hours can you safely run your air conditioning each day?

How Long Can I Run My AC Daily?

If you have an air conditioning unit that is the right size for your home, the unit should be able to cool your home in about 15 to 20 minutes. After that time, it should automatically shut off until the thermostat indicates that your home has reached a temperature that requires the unit to activate again.

This cycle should repeat as long as you have the unit activated. However, during the times of the year when outdoor temperatures stay in the high 80s or low 90s, your AC unit may run with greater frequency to keep your home cool. In some cases, it might not turn off at all. From a mechanical standpoint, that’s okay. As long as your unit is properly maintained, it can run continuously for several hours.

However, if your air conditioning unit never shuts off during the day, this is not the ideal situation. It can increase your electric bill, overwork your system, lead to premature maintenance issues, and could be a signal that there is a more significant issue with your AC unit that needs to be addressed.

Check Your Thermostat

Under some circumstances, an AC unit that runs continually is functioning correctly. Some energy-efficient models are designed to run at full bore all day long.

However, if your AC unit is not designed to run all day or your system used to shut off periodically but is now running nonstop, this could indicate a more significant issue. Some of these issues you can fix on your own. Others will require you to schedule maintenance with one of Thermo Direct’s technicians. We will evaluate your system and help you get it running smoothly again.

An incorrectly configured thermostat could be causing your unit to run constantly. Check to see if your thermostat is set to “on.” If so, you have told your unit to run consistently without turning off. It’s recommended that you switch it to “auto.” This will indicate to your system that it should only run until your home reaches the desired temperature.

Also, make sure that your system is set at a reasonable temperature based on the outdoor temperature. If it’s 100 degrees outside, but you have your AC unit set to 62 degrees, your unit will run continuously to combat the outdoor heat.

Replace Your Air Filter

A clogged air filter will impact the airflow in your home. Your unit will have to work harder and run more frequently to bring your home to the desired temperature. Additionally, dirty air filters negatively impact your home’s air quality.

The frequency with which you need to change your air filters varies based on your home’s design, location, and unique needs.

If you do not have pets and you do not have allergies, you should plan to change the AC filter once every 90 days. If there is one pet in the home, change it once every 60 days. If you have multiple pets or family members with breathing issues, allergies, or asthma, change the filter once a month.

Your Unit Is Not the Right Size for Your Home

You can compare searching for the correct size air conditioner for your home to Goldilock’s quest for the right bed and porridge. If your AC is too big or too small, it won’t properly cool your home, and it will need to work harder to get the job done.

If your AC unit is too small, it will constantly run while not effectively cooling your home. Since the unit will never achieve the desired temperature, it will keep running, spiking your electric bill and leaving your family uncomfortable.

If your AC unit is too big, you will see that it runs for shorter amounts of time but more frequently. Your home will hit the desired temperature for a short amount of time. Then, the unit will disconnect. Having your unit turn off and on constantly will increase your electric bill. It is inefficient to cool your home in this way, leading to excessive wear and tear on your unit.

At Thermo Direct, we can help you find the perfect size AC unit to cool your home efficiently. Our technicians can help you reduce your electric bill, reduce the wear and tear on your AC unit, and make your home more comfortable.

Dirty Air Conditioning Coils


Dirty AC coils can cause your unit to run nonstop. Your air conditioner has two coils. There is an evaporator coil and a condenser coil. The evaporator coil is inside your home. Its job is to absorb the humidity from your home.

The condenser coil is outside of your home. It releases the heat from inside your home outdoors. Both coils need refrigerant to function.

When the AC coils are covered in dirt and grime, there is an additional layer between the air that passes over the coils and the refrigerant that absorbs the heat. The grime serves as an insulator that makes your unit work less efficiently.

This reduction in heat transfer forces your unit to work longer and work harder to produce the level of cooling you want in your home. This means that you will have a less comfortable living space, there will be excessive wear and tear on your system, and your electric bill will increase due to wasted energy.

Your Unit Needs a Tune-Up

For as simple as the AC unit seems, it isn’t straightforward. Like any other complex piece of machinery, it needs to be tuned up and maintained regularly. Our experienced, friendly technicians at Thermo Direct can perform a comprehensive tune-up to identify problems or faulty parts to keep your unit running efficiently and prevent breakdowns.

Your Ductwork Needs Cleaning or Repair

If you have central air conditioning, leaky ductwork will allow cool air to escape your system before it reaches all the rooms in your home. The air conditioning unit will be fighting to keep the temperature down so that it will run continuously. However, the cold air is getting trapped in your walls and attic.

Raleigh, North Carolina’s Certified Electrical and HVAC Professionals

At Thermo Direct, we pride ourselves on providing Raleigh, North Carolina residents with the best heating, air conditioning, and electrical work. As members of the community, we cherish our opportunity to serve. You can count on us to assist with any of your heating, electrical, or air conditioning needs.

Our services include HVAC installation, repair, maintenance, indoor air quality services, and residential electrical services. Whether we are fixing electrical issues, maintaining your central air, or replacing a furnace, you can count on us to bring efficiency, affordability, and reliability to your home. Contact Thermo Direct today to learn more.

company icon