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Why Is My Heat Pump Freezing Up? – Answered by HVAC Expert

Why Is My Heat Pump Freezing Up?

When it’s biting cold outside, your heat pump works relentlessly to keep your home warm and comfortable.

But what if the heat pump itself falls prey to the chill, freezing up and leaving you in the cold? If you’re wondering, “Why is my heat pump freezing up?” you’re not alone.

This is a common problem faced by many homeowners, especially during the winter months. 

Let’s decipher this issue together and explore ways to prevent it.

Your heat pump’s battle with freezing begins when it absorbs the outside air, complete with excess moisture, into the refrigerant. As outdoor temperatures drop, this moisture can turn into frost on your heat pump’s coils.

If left unchecked, this frost can build up into substantial layers of ice, making it increasingly difficult for your heat pump to function correctly.

Decoding the Issue: Why Is My Heat Pump Freezing Up?

A heat pump’s fundamental function is to transfer heat from one place to another, ensuring a comfortable indoor climate. Despite its efficiency, certain factors can lead to a heat pump freezing up.

When the outside air is transferred to the refrigerant inside the pump, it brings along moisture. This moisture, when exposed to cold temperatures, may freeze on the heat pump’s coils.

The freezing, if unchecked, builds up into layers, preventing the heat pump from operating properly.

This intricate process, in its entirety, forms the crux of the question: What causes my heat pump to ice over?

7 Common Triggers for Heat Pump Freezing:

Understanding the problem is half the battle. Thus, identifying the reasons leading to heat pump freezing is instrumental in effectively diagnosing and rectifying the issue.

Let’s dissect the most common culprits responsible for heat pump freezing:

1. Hindered Airflow due to a Clogged Air Filter:

Just like how your lungs need unobstructed air for proper functioning, the heat pump requires smooth airflow to maintain an optimal temperature.

A clogged air filter acts like a barricade, restricting the airflow.

Over time, this can cause the heat pump’s coils to freeze. Regularly cleaning or replacing your air filters can help you avert this issue.

2. Inadequate Refrigerant Levels:

The refrigerant is the heat pump’s lifeblood. It carries heat from one point to another within the system, ensuring the unit functions as intended.

However, when the refrigerant levels dip, it can lead to a decrease in the system’s pressure. This can subsequently lower the system’s temperature and cause the heat pump to freeze.

3. The Impact of Accumulated Dirt on the Evaporator Coil:

The evaporator coil is a crucial component of the heat pump. Its primary function is to facilitate heat transfer for effective temperature regulation.

However, accumulated dirt can act like an insulator, obstructing the heat transfer process. This, in turn, can cause the heat pump to freeze.

Regular maintenance is pivotal to prevent this accumulation and ensure the longevity of the unit.

4. The Effect of a Malfunctioning Blower Motor on Heat Pump Operation:

A heat pump relies on the blower motor to circulate air throughout your home.

If the blower motor malfunctions, it can result in reduced airflow, which can negatively affect the heat pump’s operation and potentially lead to freezing.

5. The Role of Dirty Fan Blades in Impaired Heat Pump Performance:

The fan blades, though seemingly minor components play a significant role in maintaining optimal airflow within the heat pump.

When these blades accumulate dirt, they become less effective at moving air, leading to reduced performance. If this issue persists, the unit may end up freezing.

6. The Consequence of a Debris-filled Condenser Unit:

The condenser unit of a heat pump is designed to expel heat from your home.

However, if debris blocks it, it can impede the heat expulsion process, leading to restricted airflow and potentially causing the heat pump to freeze.

7. The Risks of Neglecting Maintenance during Winter Months:

Winter months can be challenging for your heat pump. During this time, the heat pump needs to work harder to maintain comfortable indoor temperatures.

Neglecting maintenance during these crucial months can lead to a variety of issues, including freezing.

Prevention is Better than Cure: Stopping Your Heat Pump from Freezing Up

By understanding the common triggers for a frozen heat pump, you can take proactive measures to prevent the issue.

Here are some helpful strategies to stop your heat pump from freezing up:

1. Prioritize Regular Maintenance:

Ensure regular maintenance of your heat pump, especially before the onset of colder months. A well-maintained unit is less likely to freeze up.

Since 2016 Browns Heating & Cooling is offering quality heat pump maintenance services in Chicago and surrounding areas. We offer reasonable prices and genuine advice. Our technicians are EPA-certified and factory-trained.

Book your appointment now or call us at (708) 536-8134

2. Clean or Replace the Air Filter Regularly:

Air filters play a significant role in maintaining adequate airflow. Regular cleaning or replacement is essential to prevent clogging and subsequent freezing.

3. Maintain Proper Refrigerant Levels:

Keeping the refrigerant levels in check can help avoid freezing due to low pressure. If you suspect a refrigerant leak, it’s advisable to seek professional help.

4. Keep the Evaporator Coil Clean:

Clean evaporator coils facilitate efficient heat transfer, reducing the chances of your heat pump freezing up.

5. Ensure the Blower Motor is Functioning Properly:

Regular checks on the blower motor can prevent reduced airflow, thus averting the risk of freezing.

6. Regularly Clean Fan Blades:

Clean fan blades contribute to optimal airflow within the heat pump, helping it function smoothly and efficiently.

Keep the Condenser Unit Clear of Debris: Regularly clearing debris from the condenser unit can prevent airflow restriction and subsequent freezing of your heat pump.


Understanding why your heat pump freezes up and the common triggers leading to it is the first step towards a warmer, cozier home during winter.

By ensuring proper maintenance, right from cleaning air filters to regular checks on refrigerant levels, you can keep your heat pump running efficiently.

Remember, a stitch in time not only saves nine but also keeps you warm and comfortable even in the coldest months.

Frequently Asked Questions (FAQ’s)

Why is my heat pump freezing up in winter?

Your heat pump can freeze up in winter due to several reasons. The primary cause is the moisture that the pump extracts from the outside air. When temperatures fall, this moisture can freeze on the heat pump’s coils. Other factors include blocked airflow due to clogged filters, inadequate refrigerant levels, accumulated dirt on the evaporator coil, or a malfunctioning blower motor.

Why is my heat pump freezing up in summer?

Heat pumps can also freeze up in summer, which might seem counterintuitive. However, this can happen due to factors like low refrigerant levels, which can make the indoor evaporator coil too cold, causing condensation and subsequently freezing. Moreover, a dirty filter can restrict airflow, leading to the same outcome. It’s crucial to maintain regular upkeep of your heat pump to prevent such issues.

Why is my heat pump freezing up outside?

An outside heat pump can freeze up due to external elements such as freezing rain, sleet, or snow, which can cause ice to build upon the coils. Additionally, internal factors such as low refrigerant levels, a malfunctioning defrost cycle, or blocked airflow due to a clogged filter or fan can also cause the outside unit to freeze. Regular maintenance, especially during winter, can help keep such issues at bay.

How can I prevent my heat pump from freezing up?

To prevent your heat pump from freezing up, start with regular maintenance, especially before and during the colder months. Ensure your air filter is cleaned or replaced frequently for unhindered airflow. Keep your refrigerant levels checked, and clean the evaporator coil and fan blades to maintain optimal performance. Make sure the condenser unit is clear of any debris to prevent airflow restriction. Lastly, a working blower motor is essential to prevent freezing.

What should I do if my heat pump is already frozen?

If your heat pump is already frozen, first switch off the unit to prevent further damage. You can attempt to remove the ice gently, but avoid using sharp objects as they can harm the unit. If the freezing persists, it’s crucial to call a professional HVAC technician. They can check the refrigerant levels, inspect for potential leaks, assess the defrost control, and ensure that all components of the heat pump are functioning correctly.