In typical summer heat, you should be able to hear the central air conditioner turn on, run at least 10 minutes, then shut off again. If the A/C is turning on more frequently and cycles last less than 7 minutes, you probably have a short cycling unit.

Short Cycling Concerns

Short air conditioner cycles are a concern for several reasons:

• A central A/C needs to run for at least 10 minutes to reach optimum cooling performance and humidity reduction. Shorter cycles indicate that the unit doesn’t cool as effectively and the house is less comfortable.
• Excessive on/off cycles cause the A/C compressor to use more energy, raising operating costs.
• Each time a unit turns on and off, wear and tear is incurred. Air conditioners that cycle too frequently need repairs more often and typically have shorter expected service life.

What Are Some Causes of Short Cycling?

• The air conditioner is oversized. An A/C that has excessive cooling capacity produces too much cold air too rapidly, causing the unit to cycle on and off very quickly. The BTU capacity of a new central air conditioner must be sized to specific house requirements—known as “cooling load”—by having a load calculation performed by a qualified HVAC contractor.
• Insufficient airflow. Usually caused by a clogged air filter, if airflow drops below specifications the system may quickly overheat and trigger an automatic shutdown to prevent compressor damage. After the unit cools down, the A/C restarts and short cycling recurs. Regular filter changes—your HVAC professional will change the filter(s) when they perform your maintenance tune up and if you use the 30 day filters, it is very important to follow the filter manufacturer recommendations —prevent clogged filters.
• Low refrigerant charge. If refrigerant circulating between the evaporator coil and condenser coil is insufficient, ice may form on the indoor evaporator coil, obstructing proper airflow. This may cause the A/C compressor to prematurely shut down before normal cycle has completed. Low refrigerant is almost always caused by a small leak somewhere in the system and requires professional diagnosis and repair.

To resolve short cycling issues and restore full A/C performance, contact the pros at Jackson & Sons.

Jackson & Sons, Inc.

Our goal is to help educate our customers in Eastern North Carolina (including Wayne, Johnston, Greene, Lenoir, Pitt and Duplin Counties) about energy and home comfort issues (specific to HVAC systems).