Key takeaways
- Short cycling is when the AC turns on and off too frequently to cool properly.
- A dirty filter, low refrigerant, or an oversized unit are the usual causes.
- It wastes energy and wears out the compressor, the costliest part.
- Some causes are DIY, but recurring short cycling needs a technician.
If your AC clicks on, runs for a minute or two, shuts off, then repeats, that is short cycling. It never properly cools the house, it drives up your bill, and it is hard on the most expensive part of the system. Here is what causes it.
Quick answer
Short cycling usually comes from a dirty filter, low refrigerant, a frozen coil, a thermostat in a bad location, or an oversized system. Start with the filter; if cycling continues, have a technician check refrigerant and the thermostat placement.
Why short cycling is a problem
Every time the compressor starts, it draws a surge of power and experiences wear. Frequent restarts spike your energy use and shorten the compressor's life, while the house never reaches a comfortable, steady temperature.
Common causes
- Dirty filter: restricts airflow and trips the safety limit.
- Low refrigerant: causes the system to cut out early.
- Frozen coil: see our guide to a freezing AC.
- Thermostat placement: if it is near a vent or in direct sun, it misreads the temperature.
- Oversized unit: cools too fast and shuts off before removing humidity.
What you can do
Replace the filter and make sure the thermostat is not near a heat source or supply vent. If the system still cycles rapidly, the issue is likely refrigerant, an electrical control, or sizing, all of which need a professional.
AC cycling on and off?
We will pinpoint the cause and stop the short cycling before it costs you a compressor.
