One of the most common and threatening problems for an air conditioner is short-cycling. This issue is both the symptom of a problem and the cause of more problems. Although sometimes there’s a simple fix—like changing the air filter—in other cases it requires a much bigger repair, and contacting an HVAC professional right away is pivotal.
Unless short-cycling is stopped, it will eventually lead to premature AC replacement and waste a lot of energy until then.
Facts About Short-Cycling
The term “short-cycling” is HVAC-talk for when an air conditioner or heat pump gets caught in the startup cycle and turns on and off repeatedly without completing the cooling cycle. Under normal circumstances, an air conditioner powers up the compressor and runs until the thermostat registers that it has met the temperature request.
The air conditioner then powers down the compressor. But a short-cycling AC will prematurely stop the compressor before the end of the cooling cycle, then start up again a short time later. When the compressor is turning on and off rapidly like this, it’s damaging to the system.
So what causes it? There are a number of possibilities, including:
- A clogged air filter
- An oversized or undersized air conditioner
- Low refrigerant charge due to leaks
- Air escaping through a leaky ventilation system
- Miscalibrated thermostats reading incorrect temperatures
A clogged air filter, like we mentioned above, is easy to remedy. In fact, you should be changing the air filter every 1–3 months during periods of regular system use.
An undersized or oversized system will, unfortunately, need to be replaced. But the other issues can be resolved with professional HVAC repairs.
Please do not attempt to diagnose the cause of short-cycling on your own. Beyond changing the air filter, you’ll want HVAC professionals to pinpoint what’s going on so they can adequately fix it.
Why Short-Cycling Must Be Stopped
Not only does short-cycling warn of an issue somewhere within your air conditioner, like leaking refrigerant, the strain of the constant start-stop of the compressor will shorten the AC’s service life, increase repair needs, and waste electricity. It also leads to decline in comfort. How so?
- An air conditioner uses the most energy when the compressor starts up. So when the system becomes trapped in a continual start-up process, it draws on far greater amounts of power.
- The compressor picks up more wear and tear while this goes on, and this can cause the unit to overheat and burn out. The cost to replace a burnt-out compressor is high enough to make it more cost-effective for most homeowners to replace the entire air conditioner.
- If an air conditioner stops the compressor before completing a full cooling cycle, it won’t have adequate time to actually cool your entire home.
The bottom line is, if you hear short-cycling or any sort of weird noises coming from your AC, it means something is amiss that needs to be fixed. Ignoring any sort of problem can allow the issue to grow worse until you have to replace the air conditioner altogether.