What is Short-Cycling and Why It's Bad?

What is Short-Cycling and Why It's Bad?

Short cycling is a term used in the heating, ventilation, and air conditioning (HVAC) world to explain a situation where a furnace or air conditioner turns on and off too frequently. The “short cycle” is the period of time that your HVAC equipment is actually running, and the shorter this cycle, the harder your system needs to work. But in many cases, it will require professional repairs from a trained and experienced HVAC technician (which is what we’re here for!)

Short-cycling must be remedied though, and not neglected. Otherwise, you could find yourself facing a premature replacement need for your air conditioner—and in the meantime find yourself wasting a lot of energy and subsequent money.

Short-Cycling Facts

The phrase short-cycling itself comes from what people in the HVAC field call an air conditioner or heat pump system that becomes stuck in the start-up cycle, and turns on and off rapidly, without ever completing a full cooling cycle.

Under normal circumstances, an air conditioner powers up the compressor and runs until the thermostat registers that it’s met the temperature request. The AC then powers down the compressor. But when this system is short-cycling, the compressor stops prematurely, before the end of a cooling cycle—and when this happens, the compressor is working harder than it should have to in order to do its job.

What Causes Short-Cycling?

As we said above, short-cycling is often the symptom of a problem—this problem could be from any of the following circumstances:

  • 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

Fortunately, the first problem we mentioned—a clogged up air filter—is very easy to remedy. You can, and should, be changing this filter every 1-3 months anyway as it can cause a number of other problems in addition to short-cycling.

An improperly sized air conditioner, however, is more serious. Unfortunately, the cooling system will need to be replaced if you want to restore it to full efficiency. The other problems we mentioned all require professional services.

The Consequences of Short-Cycling

So, yes, short-cycling is a symptom. But it’s also a cause of other problems. The reason for this is because:

  • An air conditioner uses the most power when the compressor starts up. When the system becomes trapped in a continual start-up process, it draws on far greater amounts of power.
  • The compressor, as a result, accumulates more wear and tear than it otherwise would, which can cause the unit to overheat and burn-out. Not only is the cost to replace a burnt-out compressor pretty high, but depending on the age and warranty on your system, it may actually be a better economical choice in the long run to replace the entire system, which may not be doable with your current budget.

The best thing you can do in order to prevent any problems with short-cycling is to invest in professional installation, maintenance, and repairs as needed. We’re happy to help with whatever your air conditioning service needs are.