Here’s what causes AC short cycling and how to fix it

“Short cycling” refers to an air conditioner that turns on, runs for only a short time, and then turns off again. This “cycle” then repeats, with the air conditioner constantly starting up. Most homeowners first notice this problem lying in bed at night, listening to the somewhat obnoxious sound of their air conditioner kicking on again and again. Of course, others notice discrepancies in their electric bill or problems with their home’s comfort. Both can be caused by AC short cycling.

If your air conditioner is short cycling, you need a professional HVAC technician to come out and take a look at it as soon as possible. As we’ll review below, short cycling can lead to a number of problems for air conditioners and heating systems, including compressor failure. Call us for professional cooling and heating service and inspections here in the Fresno metro area.

Noticing short cycling issues?

If your air conditioner or heater is short cycling, it’s time to bring in one of our HVAC experts for a closer look. At Allbritten, we help cool down Fresno homeowners with fast, friendly service and effective AC repair.

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Why is AC short cycling so bad?

Just like your car uses the most gas when you turn the ignition, your air conditioner uses the most energy when first starting up the compressor. Under normal conditions, this extra energy use doesn’t amount to much. However, with a short cycling system, the compressor is constantly in the process of starting up, which means the AC unit is drawing more energy to produce less consistent cooling. There’s no two ways about it: short cycling, if left unchecked, will negatively impact your home’s cooling costs.

Unfortunately, that’s far from the only problem. All that starting and stopping puts additional stress on the AC compressor—a vital component that is incredibly expensive to replace. In fact, in most air conditioners more than a few years old, it makes more financial sense to replace the entire system than to replace just the compressor. Protecting the compressor from this unnecessary wear-and-tear should be your top priority, and it’s why you need to take on short cycling problems right away.

But, what causes short cycling in the first place? Here are a few common reasons why your air conditioner might be short cycling:

You have the wrong-sized air conditioner

There’s a common misconception out there that the bigger an air conditioner is, the better it is. After all, at face value, it makes sense, right? A larger air conditioner should be able to provide more cooling, more quickly. However, in the HVAC world, the unit size needs to be proportional to your home’s square footage. An air conditioner that’s too large for your house is going to have just as many problems as one that’s too small.

Some common causes of AC short cycling include refrigerant leaks and improper AC sizing.

One of the most common causes of long-term, persistent AC short cycling is improper AC sizing at the time of installation. This is why you should always have an experienced, locally trusted professional install your new AC unit.

Too large of an air conditioner will turn on and cool your home down. However, running at its normal speed, it’s unable to keep going without overshooting the temperature. So, it shuts itself off. The temperature in your home begins to rise again, and the thermostat turns the system back on. This repeats, over-and-over again, with the AC turning itself on and off in quick sequence. This is a classic example of AC short cycling, and it’s really bad for your comfort, your energy-efficiency, and your system’s compressor.

In contrast, an air conditioner that’s too small is also going to have issues. It’ll turn on, run, and struggle to keep up with the demand placed on it. It’ll constantly run, using more electricity without really cooling down your home. That constant, non-stop operation puts the system under incredible stress.

There’s a sweet spot between these two extremes. It’s why we offer free in-home estimates on new air conditioners here at Allbritten. Finding the right-sized air conditioner (or heater!) for your home matters, as it can prevent short cycling and a number of other critical, long-term problems.

How to fix this:

Unfortunately, if another AC contractor installed the wrong-sized air conditioner in your home, the solution might involve replacing it with a correctly sized system. Start by giving us a call so we can advise you on your next steps and consult you on what you can do to curb short-cycling with your current system.

Your AC unit is losing refrigerant

Refrigerant is what your air conditioner uses to cool down your home. Here’s a layman’s explanation: your air conditioner moves refrigerant in a closed loop that travels inside (evaporator coil) and outside (condenser coil). Inside, the refrigerant—supercooled by the compressor—absorbs heat energy from inside air. It then transports this heat energy to the condenser unit outside and releases it, cooling back down. The refrigerant makes this journey many, many times (known as the refrigeration cycle) until the temperature inside your home matches what the thermostat says.

The refrigeration cycle relies on pressure and sufficient refrigerant. Under normal conditions, your AC doesn’t need “new” refrigerant—it exists in a closed loop and doesn’t need to be replaced or topped off. However, in the event of a refrigerant leak, the air conditioner is going to struggle to operate normally. It will start to short cycle as it attempts to meet the temperature demand of your home.

How to fix this:

If you notice your AC is short cycling, please call our team so we can send one of our experienced, friendly techs out to your home. We’ll want to run through a full diagnosis of your air conditioner to determine what the problem is, and how we can best go about fixing it. In addition to refrigerant loss, short cycling can be potentially caused by a number of other malfunctions, including problems with the compressor, electrical supply, or the thermostat itself.