One of the most common, and most frustrating, problems for an AC system is short-cycling. This problem is both a symptom of a repair need and the cause of further issues. Although sometimes there is a simple fix such as changing your air filter, in many cases short-cycling requires a much bigger repair, and the best thing you can do is contact an HVAC professional.
After all, unless short-cycling is resolved, it will eventually lead to an early demise for your air conditioner, and will waste a lot of energy until then.
What to Know about Short-Cycling
The phrase “short-cycling” is HVAC-speak for when an air conditioner or heat pump gets caught in the startup cycle and turns on and off rapidly, without completing the cooling cycle. Under normal circumstances, an air conditioner powers up the compressor and runs until the thermostat setting matches the temperature in the home.
Then, the air conditioner compressor powers down. However, a short-cycling air conditioner will prematurely stop the compressor before the end of the cooling cycle, only to start up again a short time later. When the compressor turns on and off rapidly like this, it damages the system.
So, what causes this? Well, there are a number of possibilities, like:
- A clogged air filter
- An undersized or oversized air conditioner
- Low refrigerant charge (levels) due to leakage
- Air escaping through leaky ductwork
- Miscalibrated thermostats reading temperatures incorrectly
As we mentioned above, a clogged air filter is something that’s easy to resolve. In fact, homeowners can and should be changing their air filter every 1-3 months during periods of use.
Unfortunately, an incorrectly sizes air conditioner will need to be replaced, but other problems can be resolved with professional HVAC repairs.
Remember, no homeowner should attempt to diagnose the cause of short-cycling on their own. Beyond changing your air filter, you’ll want HVAC professionals to pinpoint exactly what’s happening so they can fix it the right way.
Why We Need to Stop Short-Cycling
Short-cycling warns of a problem somewhere within your air conditioner. This problem might be leaking refrigerant or some other issue like failing components. But whatever the cause, the strain of the constant start-stop cycle of the compressor will shorten the air conditioner’s service life, increase repair needs, and waste electricity. It also leads to a decline in comfort. This is how:
- An AC system uses the most energy when the compressor starts up. So when your system gets trapped in a continual start-up process, it draws on far more amounts of power than it would under normal circumstances.
- The compressor accumulates more wear and tear as this happens, and this can cause the unit to overheat and burnout. 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 down your home.
So the bottom line here is this—if you hear your air conditioner short-cycling, or making any noises that are outside the norm, it means something is wrong and your air conditioner needs to be looked at by a pro. Ignoring any kind of problem can cause the problem to become worse until you have to replace your entire system anyway.