What Is Causing My Heat Pump To Freeze Up?

Heat pumps are efficient heating and cooling systems that can provide both warmth and coolness to indoor spaces. However, one common issue that heat pump owners may encounter is the freezing up of their units.

When a heat pump freezes, it can significantly impair its performance and even lead to system malfunctions if not addressed promptly.

To prevent this problem and ensure the smooth operation of your heat pump, it is crucial to understand the underlying causes of heat pump freezing.

Several factors can contribute to the freezing of a heat pump, and they typically involve a combination of external weather conditions, system malfunctions, or inadequate maintenance.

By being aware of these causes, homeowners and technicians can take appropriate measures to prevent or resolve heat pump freezing, thereby prolonging the system’s lifespan and maintaining its optimal performance.

Why Do Heat Pump Freeze Up?

Understanding The Reasons Why A Heat Pump Freezes Up

The coils of your heat pump can freeze if humidity from outside accumulates on them due to the air being transferred to the refrigerant.

On cold days, moisture can freeze into layers; if it accumulates enough, your heat pump will have difficulty performing correctly.

Your heat pump can actually ice up during the winter. As a result of certain weather conditions, it’s natural for the coil to be lightly covered in ice, so, in fact, the defrost cycle kicks in when excessive ice is present.

Ice is melted away using heat from the refrigerant when the unit is in defrost mode. When your heat pump gets completely covered in ice for an extended period, operating will seem impossible.

Whenever this occurs, you must have it checked by a professional technician since this indicates something’s wrong.

Troubleshooting A Heat Pump That Freezes Up

Your heat pump may have a little ice buildup even during mild winters.

A wholly frozen coil or an enclosing of ice on the heat pump could cause your system to fail, and the components might become damaged.

In order to solve or prevent heat pump issues, you must first understand why they freeze up.



Concrete slabs are familiar places for heat pumps. As the slab settles, it will obstruct the view of the ground.

ICE buildup occurs when more than an inch of settling blocks the drainage path for ice melt and impedes airflow. You should contact a technician if you suspect that’s the problem with your unit.

Cold Water

When freezing rain falls on a heat pump, the top of the unit freezes first, followed by the rest of the unit. A professional can help you remove ice from your heat pump if it can’t defrost itself after a day or if it defrosts and then freezes again.

Heat pumps are also often frozen due to water dripping from a leaking gutter. Ensure that your gutters are functioning correctly and make any necessary repairs.

Insufficient Airflow

Insufficient Airflow

Refrigeration refrigerant can get below-freezing temperatures when it is pumped through a heat pump. Air moisture can freeze on the evaporator or condenser’s coils if there is insufficient airflow through the unit.

To avoid this, make sure that leaves, debris, or snow drifts are cleared away from coils to make sure they aren’t blocking airflow. Cleaning dirty coils may prevent them from freezing.

Dirty Fan Blades

Airflow and exhaust output can be compromised when the blower’s fan blades are dirty. There is a chance of moisture becoming trapped and turning into ice. As fan blades are quite delicate, contact us immediately for rectification if this happens.

Faulty Blower Motor

Faulty Blower Motor

It can cause a freeze-up if your blower motor isn’t operating at full speed. In some cases, the fan runs intermittently, with a reduced spinning cycle, or not at all. Having it replaced is the best option if this is the case.

Filthy Evaporator Coil

Through the evaporator coil of your heat pump, the refrigerant flows. During the cooler months, it transports heat to your Wrightsville home; during the summer, it pulls it out.

Coils are less effective at transferring heat if they become dirty. If the airflow is compromised, the system can freeze up.

Whenever you observe ice on your coils, power off your heat pump, afterwards, pour hot water gently over the coils to melt the ice.

Low or Empty Refrigerant

Your heat pump’s refrigerant may leak if it is low on refrigerant. Several factors could cause this, such as a weakened solder joint, a malfunctioning valve, or an unsecured fitting.

It is also possible for components to rub against the refrigerant tank over time, eventually puncturing it and then freezing it. Make sure you turn down your heat pump when the pipes start rattling.

Clogged Air Filter

Clogged Air Filter

The clogging process occurs when air filters are left to collect particles for too long. Airflow is impeded, causing moisture to accumulate. A few examples of things that can clog your filter are dust, pet dander, and smoke.

It is recommended that you change your system’s filter as soon as it becomes blocked with dust and debris, according to the National Air Filter Association (NAFA). The rate at which your filter is clogged depends on many factors in your home.

Additional Tips For When Your Heat Pump Freezes Up

Firstly, check if your heat pump’s defrosting cycle has kicked on or if it is covered with frost or ice. Your pump should function normally again after the ice melts away.

Having run the defrost cycle for 30 minutes or more, it may still be completely covered in ice and frost after you call your HVAC contractor for a thorough inspection. You can also take the following troubleshooting steps:

Make sure you clear the outdoor coil of leaves, grass, sticks, snow and other debris around your heat pump to prevent disruption of its airflow.

You must check the indoor air vents and registers to ensure that nothing is blocking them, such as boxes, clothing, furniture, etc.

Ensure that your heat pump is clean by removing any ice that has built up on top of it. It is safer to use a garden hose to remove ice than to use a sharp object. If you use a sharp object, your unit will be damaged.

Ensure that your unit’s air filter isn’t clogged or damaged. If the filter is dirty, replace it. Ultimately, a heat pump freezing up is due to a lack of maintenance. Regular maintenance is often enough to prevent most problems.

Heating system maintenance performed by an HVAC professional, or Air Conditioning Repair professional can prevent blockages and dirt buildup that cause heat pumps to freeze.

In addition, a technician can observe settling and resolve the issue before it becomes more serious.

Final Words

By understanding these causes, you will be better equipped to identify the root of the problem and take the necessary steps to prevent or resolve heat pump freezing.

It is important to note that while this article provides valuable insights into the common causes of heat pump freezing, it is always advisable to consult a qualified HVAC professional for accurate diagnosis and repair.

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