Informational Guide

AC Short Cycling

Easily fix your Air Conditioner unit when it is short cycling by following our complete guide. Stay cool all year round.

by Josh M

Short cycling is one of the most common problems you can have with an air conditioner. It can cause damage to your AC unit and negatively impact the comfort of your home. It is also very harmful to your unit and should be repaired as soon as possible.

This guide will describe what air conditioner short cycling is and explain how to fix it.

Condenser Unit of Aircon AC

Short cycling is when your air conditioner stops its cooling cycle too soon, then starts the cooling cycle again a brief time later. Short cycling can be caused by problems with your thermostat, leaking refrigerant, or a clog in the air filter.

A fully functional air conditioner should cycle for about fifteen minutes, 2–3 times every hour. If your AC cycle is consistently shorter than fifteen minutes, your unit might have a short-cycling problem.

You will need to get this problem fixed, since short cycling damages an air conditioner’s parts. It can even burn out the compressor, in which case you will have to get a new AC unit. It’ll save you money to take care of short cycling before it completely destroys your unit.

What Causes HVAC Systems To Short Cycle?

There’s more than one reason why your air conditioner cycles on and off too frequently. Common factors that contribute to short cycling are AC unit size, electrical issues, or problems with certain components. You will have to do some air conditioner short cycling troubleshooting to find out what the problem is.

Oversized AC System

A bigger AC unit does not guarantee better air conditioner performance. If your AC unit is too big for your home, it can start to short cycle.

This happens because a larger-than-necessary air conditioner will cool down your home too fast. Find out what size of air conditioner is best suited to your home, and keep in mind that bigger isn’t always better. If your current unit is too big, you should replace it with the right size AC unit to prevent short cycling.

Frozen Evaporator Coils

Evaporator coils in your AC unit remove hot air from your house. If you neglect your evaporator coils, they can freeze. This means your air conditioner can’t take in hot air as efficiently as it used to. The AC system will overheat and turn off, which leads to short cycling.

Thermostat Issues

AC unit short cycling might not be caused by a problem with the actual AC unit. It’s possible that your thermostat is malfunctioning and giving your unit inaccurate temperature readings. This usually happens because of the thermostat location. If it’s in direct sunlight or near a window with a draft, it can mistake the temperature of the whole area.

A thermostat issue is easy to fix, though. A repair expert can either replace your thermostat or move it to a different location in your house.

Clogged Air Filter

We’ve all seen dust and debris gathering on our vent covers thanks to our air conditioner. The airflow can also cause dust and debris buildup in unseen areas. If your AC unit’s air filter gets clogged, it will impede overall airflow.

A clogged air filter prevents enough heat from reaching the evaporator coil. We already mentioned what can happen to evaporator coils if they don’t get enough heat.  We recommend cleaning your air filter monthly, especially during warmer months when you use the air conditioner.

Low Refrigerant

Another cause of short cycling is a low level of refrigerant. Like frozen evaporator coils, this can cause your AC unit to overheat. When the unit overheats, it will turn on and off frequently.

If your air conditioner is low on refrigerant, it’s probably because you’ve got a leak somewhere. Refrigerant keeps the compressor running smoothly, so you need to call a repair expert immediately.

Electrical Issues

If the wiring in your air conditioner’s controls gets frayed or malfunctions, it can interfere with the timing of your AC unit. It could also be caused by a faulty capacitor. This means that the unit doesn’t know when to turn on and off, so it begins to short cycle. When dealing with electrical problems, don’t try to do the repairs yourself. Call a professional electrician.

Why Is Short Cycling Bad? (Common Consequences)

Firstly, HVAC short cycling causes your air conditioner to use more energy. This is because the AC uses the most power when the compressor starts up. Since short cycles mean the unit starts up more frequently, it uses more energy than it should.

Another effect of short cycling is increased wear and tear on the compressor. This is because the compressor only kicks in when your unit starts up. More startups mean more compressor use.

Short cycling also has an impact on your finances. Since starting up the air conditioner takes more energy, short cycling will rack up a higher electricity bill for you.

How To Fix Short Cycling Air Conditioner (Common Solutions)

If your air conditioner is short cycling, the first thing you should do is change your air filter. Make sure you turn the unit off before you change the filter. Once you’ve replaced the air filter, turn the AC unit back on and see if it cycles properly.

Check the location of your thermostat. Your thermostat should be at a central location in your house. If it’s by a window where it’s drafty or in direct sunlight, your thermostat probably isn’t taking accurate readings of your house’s temperature. Moving the thermostat to a central location will help with this.

Another common way to fix air conditioner short cycling is to defrost frozen evaporator coils. If the coils are frozen, turn off the air conditioner until the coils defrost completely. If this doesn’t resolve the problem, you will have to call an HVAC professional to troubleshoot other potential problems.

Mini Split Short Cycling

Unlike central air conditioners, a mini-split doesn’t come with a wall thermostat. The unit itself detects the temperature, so its position is important if you want an accurate temperature reading. If your mini-split is short cycling, try moving it to a more central part of the house. If this doesn’t work, check the air filter, evaporator coils, or call an HVAC professional.

Portable Air Conditioner Short Cycling

If your portable air conditioner is short cycling, it’s probably because the unit is too big for the room. If your air conditioner is too big, the cool air rebounds off a wall and back toward the air conditioner. This produces an inaccurate reading of the temperature of the entire house.

How To Prevent The Air Conditioner Unit From Short Cycles

The main way to prevent short cycling in your AC unit is regularly scheduled maintenance. Catch clogged air filters or frozen evaporator coils before they cause major problems. Have an HVAC professional perform an AC inspection at regular intervals.

Put your thermostat in a central location. By keeping your thermostat away from windows, you can increase its accuracy in reading temperatures.

Make sure your AC unit is the right size for your home. Having a unit that’s too big will cause your house to cool too fast, which can lead to short cycling. If you’re buying an air conditioner, do your research and know what size you need beforehand.

rheem air conditioner

People Also Ask (FAQ)

Is the Trane AC brand known for short cycling?

Like all air conditioners, the Trane AC unit can short cycle if it is too big for your home, has a clogged air filter, or needs the evaporator coils defrosted. Short cycling can also occur because of electrical issues or a malfunctioning thermostat.

Can a thermostat cause short cycling?

If your thermostat isn’t centrally located in your house, you may experience short cycling in your AC unit. This is because the thermostat isn’t reading the average temperature of your house.

Can a bad capacitor cause short cycling?

The most common sign of a failing capacitor is air conditioner short cycling. If the capacitor isn’t keeping up a strong enough airflow, the air conditioner can start to short cycle.

Conclusion

A properly-functioning AC unit should cycle for 15 minutes two or three times per hour. If your air conditioner is frequently turning on and off, you’ve got a problem with short cycling. Short cycling can damage your air conditioner and increase your electricity bill.

To prevent short cycling, perform routine maintenance like changing the air filter and defrosting the evaporator coils. If your AC unit is short cycling, call an HVAC professional.

Josh M

My name is Josh and I am obsessed with the HVAC industry. I created this website to help HVAC techs of all levels get the best out of their heating & cooling systems. I have spent thousands of hours studying air conditioners, heaters and home air products so you can learn & buy with confidence. Learn more about the team here.

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