Why is my Heat Pump Turning On and Off Frequently? A Florida Tech Answers

August 20, 2019

Sick of your heat pump cycling on and off all the time?

We don't blame you—it's uncomfortable and annoying. Plus, a heat pump that's turning on and off frequently can wear out your system, causing expensive repairs.

If your heat pump is frequently turning on and off, there could be a variety of reasons including:

  • An oversized unit
  • Dirty air filter
  • Refrigerant leak
  • Thermostat installed in the wrong location

Below, we’ll walk through each of these potential issues and their solutions. Rather have a professional assess your heat pump and determine the issue? We’d be happy to help! Learn more about the heat pump repairs we offer or…


Reason #1: An oversized unit

If you recently had a heat pump installed and are noticing that it’s turning on and off frequently, you could have an oversized system.

When a heat pump is too large for your home, it quickly heats or cools your home and then shuts off, causing the constant on/off cycle you’re noticing.

If you think this could be your issue, our first suggestion would be to contact the technician who installed your system. Before installing your heat pump, a technician should have conducted a load calculation and determined the correct size heat pump for your home. If they didn’t do that, you might have an incorrectly sized heat pump.

We know—it’s really frustrating to think you need a new heat pump, especially if you just had yours installed recently.

The good news?

If your heat pump was installed recently, the contractor who installed your system should replace it for free. Most contractors offer a 6-month to 2-year labor warranty on any equipment they install. If they did install the wrong size, the contractor should replace your heat pump with a correctly sized unit for free.

Reason #2: Dirty air filter

Another reason your heat pump may be cycling on and off could be because of a dirty air filter. Your system cools/heats your home by drawing in air from your home and blowing that air over cold coils called evaporator coils.

When your air filter is clogged or dirty, the amount of air blowing over the evaporator coils is reduced, which can cause them to freeze over. Your system has safety checks in place which can turn your AC off due to a frozen or malfunctioning evaporator coil, which may be why your AC is continuously cycling on and off.

clean vs dirty air filter

Example of a clean air filter (left) next to a dirty air filter (right).

If your air filter looks like the filter on the right, it needs to be replaced. As a general rule of thumb, you should change your air filter every 1-2 months to ensure that it’s clean and providing your system with adequate air supply.

Reason #3: Refrigerant leak

Heat Pump Diagram

Your heat pump either dispels heat or absorbs heat via refrigerant lines. If there is a leak in your refrigerant lines, the pressure of your AC compressor (indoor unit) can lower.

Your AC system likely has a safety feature that will shut your system off when it senses this low pressure, resulting in the on/off cycle you’re noticing.

If this is your issue, you’ll need to hire an HVAC professional to come to check out your system, repair or replace your refrigerant line, and refill your system’s refrigerant supply. Although refilling refrigerant may sound like an easy fix, refrigerant is a potentially harmful substance, so we wouldn’t suggest attempting this repair on your own.

Reason #4: Thermostat installed in the wrong location

Your thermostat reads the temperature of your home, triggering your heat pump to turn on and off. However, if your thermostat is located close to a vent or window, it may improperly read the temperature of your home, causing your system to shut off.

If this is your issue, you’ll need a technician to come to your home and move your thermostat.

Need a heat pump repair? Hire Florida’s Best: Red Cap

Our HVAC technicians have had years of experience serving the homeowners of Tampa Bay with all kinds of heat pump repairs. If you’re experiencing one of the issues we’ve listed above (or any other heat pump issues), we’d be happy to help.