AC Keeps Turning On and Off

AC Keeps Turning On and Off

If your air conditioner keeps turning on and off repeatedly, your system is most likely suffering from two dreaded words: short cycling. Every air conditioning system runs on something known as the refrigerant cycle, which works to bring the heat out while simultaneously bringing cool air in on a set cycle. However, this process can be disrupted and cause your system to short cycle.

9 Reasons Your AC Keeps Turning On and Off & How to Fix It

Luckily, short cycling is usually an easy fix! Here are some of the most common reasons your AC keeps turning on and off and how to fix them.

1. Dirty Air Filter

Clogged air filters are one of the most common causes of AC problems. A dirty air filter restricts airflow to your AC system and can cause multiple problems, including short cycling.

Solution: Check and replace your air filters if they’re dirty.

Related article: How Often Should I Change My AC’s Air Filter?

2. Dirty Condenser Coils

If you haven’t performed AC maintenance in a few years, it’s possible your AC’s condenser coils are caked in dirt and debris. Condenser coils are located inside the outdoor AC unit and release the heat from inside your home. If they’re clogged with too much dirt and grime, your AC system could overheat and turn off.

Solution: Clean your condenser coils or have a local HVAC company perform routine AC maintenance.

3. Thermostat Issues

When your air conditioning system is short cycling, check the thermostat. While the thermostat may seem like one small component of your entire system, this little device controls the entire temperature of your home, so it’s important that it functions properly.

If the thermostat is not sensing the temperature accurately and communicates misinformation, it will signal the air conditioning system to start and stop frequently.

If you notice your thermostat screen is blank or fading it may be low on batteries and losing power intermittently. This will cause your AC system to turn on and off when your thermostat loses battery power.

Solution: Try replacing the batteries and restarting the thermostat. If neither solution fixes your problem, call an HVAC professional to diagnose the thermostat.

4. Bad Thermostat Placement

Your thermostat measures the temperature of the air around it to determine when to turn your AC system on and off. Your thermostat may have inaccurate readings if it’s located:

  • Near a window and receiving direct sunlight
  • Close to a room that’s always hotter than the rest of the house, such as the kitchen or bathroom
  • Beneath supply air vents, receiving direct airflow

Any of these situations could cause your thermostat to receive inaccurate, poor readings and think your house is hotter or colder than it really is.

Solution: Move your thermostat to a better, more centralized location.

5. Oversized Air Conditioner

Have you always had this problem? Or did it only start recently when you installed a new AC system?

A system that is too large won’t have an appropriate refrigerant cycle and will face numerous problems, like cooling your home too quickly and then turning off shortly after it turns on. This might sound like a good thing, but in reality, your home is cooling unevenly and your AC will turn back on again sooner than it should need to.

Not only are these issues inconvenient, but they can cause bigger problems for your home, such as:

  • Higher energy bills: Turning your AC on and off constantly uses more energy
  • More repairs: Not only does short cycling use more energy, it puts more wear and tear on the parts in your AC
  • Shorter lifespan: More wear and tear means the average life expectancy of your air conditioner will be shorter.

Solution: Contact a local HVAC company for a second opinion on the installation.

6. Refrigerant Leak

If your AC system has a refrigerant leak, your air conditioner could be too low on refrigerant. Refrigerant is a coolant that cycles through your AC system, absorbing heat and cooling down the air inside your home.

It’s a common misconception that refrigerant is used up as part of an AC system’s cooling process. But the truth is low refrigerant levels are caused by small holes that allow the refrigerant to escape.

When your AC system is low on refrigerant, the compressor will malfunction and shut off your compressor because the pressure is too low. Then, when your compressor is off, the pressure will rise again and it will turn back on. This creates a short cycle that causes massive amounts of wear and tear on your AC system, potentially resulting in parts going bad or system failure.

Solution: Refrigerant leaks can be dangerous, call a local HVAC company to find and fix the leak.

7. Compressor Failure

Just like when there’s a refrigerant leak, if your AC compressor is overheating, malfunctioning, or starting to fail, it will result in your AC system shutting off and starting back up shortly.

Solution: Contact a local HVAC company to diagnose and replace your AC compressor.

8. Frozen Evaporator Coils

If your AC system has airflow issues or a refrigerant leak, it’s possible your evaporator coils are freezing up. When this happens, your AC system will shut off until the ice thaws and then turn on again.

Solution: Check your outdoor AC unit for ice buildup, if you’ve already checked your air filters, then you likely have a refrigerant leak and will want to call a local HVAC company to find and fix the leak.

9. Electrical Problems

Electrical problems are a common cause of short cycling. Often times, there may be an issue with the electrical supply line or the capacitor could be broken.

Solution: Call a local professional electrician. Electrical problems are not only difficult to diagnose but diagnosing an electrical problem can be dangerous for even the most knowledgeable homeowners.

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