Why Does My AC Keep Turning On and Off?

Your AC doesn’t constantly run. It runs for a while, cools the house down, shuts off, and waits. Then it starts again once the temperature reaches whatever you’ve got your thermostat set to. That’s how the system is supposed to work, at any rate, but if you’ve started noticing the system clicking on and off every few minutes, barely running before it stops again, something’s wrong. This is called short cycling, and it’s a big problem. Let’s look at some of the most common AC short cycling causes for Las Vegas residents.

The System Is Too Big for Your Home

This one surprises people, but bigger isn’t always better in HVAC. If your AC unit is oversized for the square footage it’s cooling, it’ll bring the temperature down so quickly that the thermostat is satisfied before the system has run through a full cycle. The unit shuts off, the temperature creeps back up, and the whole thing starts over again two minutes later.

An oversized system also doesn’t run long enough to really dehumidify the air (moisture is a problem in and around Las Vegas, but only during certain times of year). If your system was installed without an accurate load calculation, or if you’ve upgraded to a larger unit thinking it would cool your home better, oversizing may be your culprit. Note that you can’t fix an oversizing issue. You’ll need a new HVAC system installed.

Your Refrigerant Is Low

Low refrigerant causes a range of problems, and short cycling is one of them. When refrigerant levels drop below what the system needs, pressure in the refrigerant circuit falls. Most modern HVAC systems have a low-pressure safety switch that protects the compressor by detecting that drop and shutting the system down. The system restarts, pressure drops again, and the switch trips again. Rinse and repeat. If you notice short cycling alongside warm air from the vents or ice on the refrigerant lines, low refrigerant could be the issue.

Heat Spikes and Monsoon Season

Both heat and humidity are among the many AC short cycling causes. During the peak of the average Las Vegas summer, when it’s pushing 115°F, your condenser unit is trying to dump heat into air that’s already superheated. If the high-pressure side of your refrigerant circuit climbs too high, a high-pressure safety switch will trip and shut the system down, just like the low-pressure switch does on the other end.

Then there’s monsoon season. Las Vegas residents know the summer monsoons bring something rare for the area: humidity. Even brief spikes in humidity can affect how your system’s sensors read conditions.

Should You Call for Help?

Short cycling is usually not something you can DIY your way out of. Our AC maintenance service can help catch issues before they become major problems, and our AC repair service will get you back up and running as quickly as possible.