Why Is My AC Short Cycling?

It’s a warm day, and your air conditioner starts working to cool down your home, making a familiar hum. And then, the AC stops—earlier than you expect it to. It keeps starting and stopping soon after. This continues until you start to wonder if something is wrong.

Your AC is “short cycling.” It’s when the system quickly reaches your set thermostat temperature and then shuts off without completing a full cooling cycle. While not uncommon, it’s important to address it soon than later. Short cycling puts extra stress on your system’s components, particularly the vital compressor part, spiking your utility bills and potentially leading to a breakdown.

Several reasons can cause your AC to short cycle, including:

Below, we’ll walk through each issue and what you can do to fix it.

Your AC needs a steady intake of warm air to run efficiently. If something prevents it from pulling in enough airflow to cool your home, its critical components (such as the blower fan) will need to work harder to compensate.

Due to increased stress, the components will overheat and then turn off to prevent damage. Once the parts cool down, the air conditioner will turn back on.

A dirty air filter is a major culprit of restricted airflow. Check to ensure it’s not thickly congested with lint, dander, and dust that can choke off the airflow your air conditioner needs. You should change your filter every 1-3 months.

Other reasons for restricted airflow include blocked return and supply vents. Make sure furniture and curtains don’t block them or aren't closed in unused rooms.

An air conditioner uses a substance called refrigerant, which absorbs and then dumps heat out of your home. Refrigerant circulates throughout the system in a closed loop, and the AC uses the same charge of refrigerant for its entire lifespan. Or, at least, it should.

If there is a refrigerant leak, the AC short cycling can occur. Low refrigerant levels reduce the overall pressure in your AC system, triggering a safety switch to turn off the compressor, which pumps the refrigerant in and out of your home. When the compressor shuts off, the pressure increases again, and the AC starts back up. The rapid on/off cycle continues when the AC system senses there isn’t enough refrigerant.

Contact a professional HVAC technician to seal the leak and recharge the refrigerant. Ensure that the technician repairs the leak before they refill your refrigerant. Continually refilling the refrigerant without sealing the leak will not resolve the problem.

Your thermostat might be the problem causing the short cycling. It shuts off and turns back on when it has a bad connection to the compressor or senses inaccurate temperatures.

How does this happen? Well, a thermostat assesses your home's temperature and signals your AC system to turn on to cool it. However, a thermostat close to an AC vent or near a window cannot accurately read your home's temperature. A professional technician can move your thermostat to a better location in your home to accurately read the temperature.

Surprisingly, a newly installed air conditioner can also short cycle. If the installers didn’t take the time to properly size the system to meet the cooling needs of your household, the AC might be oversized. The oversized AC will short cycle because it lowers temperatures so rapidly that the thermostat thinks the cooling cycle is finished when it isn’t and quickly shuts off the system.

Not only does an improperly-sized AC causes short cycling, but it also causes:

• Increased energy bills
• A shortened AC lifespan
• An increased chance of an expensive repair or replacement

Contact a professional technician to come to your home and perform a load calculation. Used by industry professionals, load calculations will determine how much heat needs to remove from your home and what size of AC your home needs to have installed. Replacing your AC with a properly-sized one can seem like a significant upfront investment, but it will save you money throughout its life. Also, if your system is within your labor warranty, this may help you with the cost of replacing the oversized AC.

Contact Golden Rule PHC to investigate your short-cycling AC and determine what needs fixing. Get a 5-star AC repair or replacement from the team with the fastest response times in the Des Moines Metro area.

Homeowners have relied on us for over 20 years to service and install their HVAC equipment. No matter your AC request, we’ll provide you with various repair recommendations suited to your home and budget. Not to mention, we honor a 100% satisfaction guarantee for our work.

Call us today at (515) 393-4526 or click the button below.