Why is my AC unit turning on and off frequently?  Pippin Brothers, Lawton, OK
May 15, 2015

If your AC is turning on and off frequently, you’re experiencing something called short cycling, one of the most common air conditioning problems among homeowners.

It can also be the most costly. That is, if it’s not caught and fixed in time.

Here to help are the most common causes of short-cycling and ways they can be corrected.

Thermostat location

Think of your thermostat as your AC’s trusty informant–using the temperature around it to decide when to turn the system ON and OFF. That’s why the air around your thermostat should be an accurate representation of the temperature throughout your home.

Think about it: Thermostats located too close to a supply air vent or near a window with direct sunlight, make your thermostat think your home is either colder or warmer than it really is, creating a never ending ON/OFF battle for you and your AC system.

What we recommend: This is a relatively simple fix – just find a better centralized location with the help of your AC technician.

Dirty air filter

Oh, the dirty air filter. It’s the cause of most AC malfunctions and understandably so. A dirty filter restricts airflow and restricted airflow causes a whole slew of problems, including a frozen evaporator coil. This can cause the unit to malfunction by turning on and off in short bursts.

What we recommend: Replace or clean your dirty air filter on a regular basis to avoid bigger, more expensive problems. If short-cycling still occurs, you may want to call a professional to check out your evaporator coils and other internal equipment.

Hint: Try FilterFetch and never forget to change your air filters again! Contact us for more info.

Leaking Refrigerant

Refrigerant (or “Freon”) is a coolant that flows through your system to help absorb heat and cool down the air inside your home. When refrigerant is low, it messes with the pressure levels needed for your compressor to operate the way it should.

Most compressors have a low pressure control that acts as a safety switch by shutting off your compressor. When your compressor is off, pressure rises and triggers it to restart again, creating a rapid on/off cycle that can cause serious system damage or possible failure.

What we recommend: Call an AC technician to find and fix the leak.

Oversized AC

If you’ve recently replaced an AC and it’s short cycling or have a system that’s always had the problem since the day it was installed, there’s a good chance the system is too big for your home.

A large AC means your home is being cooled rapidly. That’s why it’s frequently turning on and off.

This is a problem for a few reasons:

  • Runs up your energy bill (because turning on an air conditioner requires more energy)
  • Increases the chance of a breakdown
  • Shortens your air conditioner’s lifespan.

What we recommend: Get a trustworthy AC company to do a heat load calculation to make sure your air conditioner isn’t oversized. Many HVAC companies also provide airflow and whole house evaluations to make honest assessments on issues involving airflow and poorly installed systems.

Next step

Considering short cycling involves your compressor (the mechanical heart of your entire system). We highly recommend contacting a trusted professional who can clearly diagnose and solve the problem before bigger and more expensive issues occur.

If you’re in Lawton, OK or the surrounding areas we’d be happy to help. Just contact us.