Why Does My Air Conditioner Turn On and Off Frequently?

Columbus AC technician troubleshooting

If your home’s air conditioning system runs for a couple of minutes, turns off for a couple minutes, then turns back on again in what seems like an endless cycle, it is probably experiencing a phenomenon called short cycling.

Short cycling can create many problems for your AC system, most significantly it can cause higher repair bills and drive up your utility bills.

This is actually a fairly common problem in the central Ohio area, and can be caused by a number of different problems within the function of your air conditioner. Short cycling is easy to recognize, but it’s quite difficult to troubleshoot without an onsite technician to see and hear the problem and run diagnostics on your system.

Let’s review some of the most common reasons why your AC might be short cycling.

Thermostat Location, or a Faulty Thermostat

The thermostat installed in your home has an important job: measure the current temperature, then turn the AC or heating system on or off to get your home to the desired setting.

For proper functioning, the thermostat should be placed in a central location of the home. Ideally, it should be installed in a location away from windows, air vents or where the sun can shine directly on the unit.

If the thermostat is near an air vent or register, the cool air coming from the vent could fool the thermostat into thinking the home is actually cooler than it really is.

A thermostat installed near a window may switch on and off frequently because the sun heats up the surrounding area, causing the thermostat to think the home is actually warmer than it really is.

Another common problem could be the thermostat itself is bad, especially an older mercury switch thermostat, or it may need to simply be calibrated.

The Air Filter is Dirty

It’s kind of ironic, because we mention this “hot tip” in almost every article we write. But it happens to be true – a dirty filter is one of the most common cause of air conditioning issues, and can lead to much more serious problems in the system.

A dirty air filter can restrict airflow to the air conditioner, often to the point where the coil actually freezes. Freezing would trigger a safety switch and cause the AC to prematurely shut down, often long before it was done cooling the home.

After the system warms up and thaws a bit, and the switch resets itself, the system can turn itself back on and cycle through the process all over again.

Coolant (Freon/Puron) Leak

Refrigerant is the lifeblood of an air conditioning system. Coolant in the system is forced through a condenser in the outside unit on the typical air conditioner, moving it into the A-coil or condenser coil that sits atop the furnace blower motor fan. As warm air is blown across the fins of the A-coil, the coolant warms into a liquid format and moves back into the outside unit to start the process all over again. The coolant also carries lubricant for the motors or pumps is travels through in its cyclical journey to keep your home comfortable, so it serves a double purpose.

Low coolant levels can cause a number of issues, particularly freezing up the coil and short cycling.

As an important side note: the refrigerant in your air conditioner is contained in a closed system and only may be handled by an EPS certified technician. If your system is low on refrigerant, that means it has sprung a leak somewhere. If you don’t repair the leak before you have the system topped off again, you’ll be calling an HVAC contractor back again to re-fill your system. And refrigerant isn’t cheap; neither are frequent service calls.

AC System’s Coils Are Dirty

Failure to perform routine annual maintenance on the HVAC equipment in your home can also cause short cycling, for many of the same reasons listed above for a dirty filter.

The evaporator coil, or A-Coil, is installed above the furnace blower mower in your indoor unit. They act like a vehicle’s radiator, where the coolant in that system helps remove heat from the car’s engine. Car radiators don’t really get dirty, but a home’s condenser coils can get clogged with dust, dirt, pet dander, and other contaminants that restrict airflow and prevents it from doing its job properly.

The coils on the outside unit, called condenser coils, perform the same function to dissipate heat from the liquid refrigerant before it gets compressed back into a gas form and forced back indoors through the closed system. The outdoor unit is particularly susceptible to clogging by organic material (especially dogwood tree pollen) that can cause it to overheat.

Either of these coils clogging can cause the system to overheat and shut down… then restart after its cooled.

Size Really Does Matter (with an Air Conditioner)

If short-cycling has been a frequent problem with your AC system, especially since it was new, it’s possible that central air conditioning unit installed in your home is just simply too big for the size of the space and the amount of air it needs to move to cool properly.

An oversize AC will cool the home quickly, then shut off because it’s super efficient. On the surface, you may think this is desirable, but in reality the system doesn’t have time to dehumidify the air properly, so it shuts down and restarts frequently.

When an air conditioner is sized just right for the size of your home, it will work to cool your home efficiently during a full cooling cycle, shut off for awhile, then run again when the temperature approaches the target room temperature again. On a hot, hot central Ohio summer day, it could run for hours on end without stopping. Any one of the issues listed here could cause it to short cycle, burn up unnecessary energy, and cause extreme wear and tear on the system.

Dor-Mar to the Rescue!

Dor-Mar Heating and Air Conditioning can play detective and sort out any short-cycling issues in your home, then offer cost-effective solutions. Contact us today, and we’ll help find and fix the source of the too hot or too cold room problem! Contact Dor-Mar today.

Schedule an appointment for HVAC system troubleshooting or maintenance with us today by using our online contact form, or call one of our seven neighborhood offices listed below. We pride ourselves on our customer-focused service, and our reviews show it.

NEWARK  740.345.6639 • COLUMBUS 614.238.6689 • DUBLIN 614.545.8939 • REYNOLDSBURG 614.365.1579 • WESTERVILLE 614.381.1540 • GROVE CITY 614.595.3098 • ZANESVILLE 740.454.2420

Dor-Mar…Your Climate Hero!

*Please note: neither the Centers for Disease Control(CDC), the World Health Organization (WHO), nor the manufacturer of our UV-C Devices have officially announced whether UV-C kills the current strain of Corona Virus (COVID-19). We urge you to err on the side of caution until we have a definitive answer, and take other measures to prevent the acquisition or spread of this virus.


In continuous operation since 1962, our expertise goes beyond just the mechanicals of your HVAC system. We’re pretty handy when it comes to ductwork and system-wide maintenance as well. For top-notch service keeping your home’s heating and cooling system clean and your family breathing clean, filtered air, contact Dor-Mar today.

Our team offers a wide array of routine maintenance and emergency services for your heating and cooling system, allowing your family to breathe fresh, safe, clean air and be comfortable year-round. We also offer a number of add-ons to your HVAC equipment that can improve your home’s Indoor Air Quality (IAQ), such as electrostatic air filters, whole-house humidifiers, duct cleaning, Ultraviolet-C lighting systems, and more.

Schedule an appointment for HVAC system troubleshooting or maintenance with us today by using our online contact form, or call one of local offices listed below. We pride ourselves on our customer-focused service, and our reviews show it.

Dor-Mar…Your Climate Hero!

Picture of Steven Brewer<br/>HVAC Expert & Owner

Steven Brewer
HVAC Expert & Owner

I started in the HVAC business as a young man, with my father putting me in crawl spaces to run ductwork while on summer vacation from school; I began full time in our family HVAC business at the age of 19. I obtained my state commercial HVAC license at 25. I'm married with three kids, and I love boating, fishing and hunting.

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