Potential Causes for a Short-Cycling Air Conditioner


A home's air conditioner is a vital part of the HVAC system and is essential to indoor comfort during the warmer summer months. However, when an AC unit starts short cycling, it can be a sign of a bigger problem. Short cycling is when an AC turns on and off more frequently than normal, and it can be a sign of an issue with the thermostat or a refrigerant leak. Luckily, this issue is usually repairable and can be diagnosed and fixed quickly. Keep reading to learn more about the possible causes if your air conditioner keeps turning on and off.

Low Refrigerant

Low refrigerant is one of the most common causes of AC short cycling. When the refrigerant level is too low, the air conditioning process becomes inefficient, and the unit will continually cycle on and off as it struggles to reach the desired temperature. This short cycling can cause an increase in energy consumption, as well as wear and tear on the system.

Low refrigerant is typically caused by a refrigerant leak somewhere in the system. It can also be caused by a malfunctioning expansion valve, which is responsible for regulating the amount of refrigerant entering the evaporator. If the expansion valve is not working properly, it may be allowing too much or too little refrigerant into the system, resulting in low levels and short cycling. In some cases, the system may also be undercharged or overcharged, causing the same issue. Regardless of the cause, it is important to address low refrigerant levels as soon as possible in order to prevent further damage to the system and ensure that it is functioning as efficiently as possible.

Dirty Air Filters

Dirty air filters are one of the most common causes of HVAC short-cycling. Air conditioners rely on a constant supply of fresh, clean air to operate properly, and when the air filter becomes clogged with dust, dirt, and other debris, it can impede the flow of air through the system. This can cause the unit to shut down prematurely, resulting in short cycling. In addition, the build-up of contaminants on the air filter can cause the AC to become less efficient, resulting in higher energy bills. A dirty air filter can also contribute to poor indoor air quality.

To prevent this from happening, the air filter should be checked and replaced on a regular basis. It is suggested that you change your HVAC air filter at least every 90 days. This will help ensure that the system is receiving an adequate supply of clean air and will be able to operate at its peak efficiency.

Thermostat Malfunction

Your thermostat serves as the director for HVAC operations, calling for air conditioning based on your desired temperature setting. A thermostat that fails to accurately measure the temperature in the home and sends incorrect signals to the HVAC unit can cause short cycling. Common causes of thermostat malfunction include incorrect settings, incorrect wiring, failing batteries, or a malfunctioning component.


To remedy this issue, it is important to check the thermostat settings and make sure they are accurate, check the wiring to make sure it is connected properly, and replace failing batteries. If these steps do not resolve the issue, it is important to contact a professional to diagnose and repair the underlying issue.

If your air conditioner is short cycling, it can be caused by a range of factors, including low airflow, worn parts, and dirty filters. It is important to identify the root cause of the issue and take the necessary steps to fix it in order to prevent further damage to the system. Scheduling regular seasonal maintenance will help ensure that your unit remains in good working order throughout the year.

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