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Heat Pump Struggles In Cold Weather – Causes & Fixes

Heat pumps have revolutionized the way we maintain comfortable temperatures in our homes. 

However, as winter approaches, many homeowners find their trusty heat pump struggles in cold weather. Why is that? The answer lies in the inherent challenges that cold weather presents. 

Heat pumps are designed to harness warmth from the external environment and channel it indoors. However, when the external temperatures plummet, these pumps face challenges, making it harder to maintain cozy indoor temperatures.

Heat Pump Struggles in Cold Weather – Quick Answer

For those who cherish the elegance of fashion, imagine wearing a light summer dress on a frosty winter day. It’s beautiful but not quite up to the task, right?

Similarly, heat pumps, while efficient in milder climates, can find it challenging to extract warmth from the frigid outside air and transfer it inside during colder months.

Factors like worn-out components, improper sizing, and external obstructions can further exacerbate this struggle. But fret not, with the right understanding and care, one can optimize their heat pump’s performance even in the chilly embrace of winter.

10 Reasons Why Heat Pump Struggles in Cold Weather

Heat pumps are a marvel of modern technology, offering both heating and cooling solutions for many homeowners. 

However, like all machines, they have their limits, especially when confronted with the harsh realities of cold weather. 

Let’s delve into the ten main reasons heat pumps might struggle in colder climates:

Inherent Design Limitations

Heat pumps, by design, are exceptional tools for efficiently maintaining comfortable temperatures in our homes. 

Their primary function is to transfer heat, which is different from traditional systems that generate heat. 

Think of them as devices that “move” warmth rather than “produce” it. In regions where the climate is predominantly warm, this distinction doesn’t present many challenges. 

The heat pump can effortlessly extract the abundant warmth from the outdoors and transfer it inside. However, as we venture into colder climates, the scenario changes.  

The ambient heat available outside diminishes significantly, which means the heat pump has to exert more effort to extract the limited warmth available. 

This additional strain can lead to operational inefficiencies and reduced output, making it challenging for the system to maintain desired indoor temperatures.

Reduced Efficiency with Falling Temperatures

The science of thermodynamics plays a pivotal role in the operation of heat pumps. As temperatures outside plummet, the disparity between the warmth inside our homes and the cold outside intensifies. 

This widening temperature difference means the heat pump has to work even harder. Imagine trying to extract warmth from an environment that’s rapidly losing it; it’s akin to squeezing water from a drying cloth. 

As the heat pump strives to pull this diminishing warmth from the cold outdoors, it consumes more energy, leading to a decline in its efficiency. 

The result is a system that works harder but may not necessarily deliver the expected comfort levels, especially during extreme cold spells.

Defrost Cycle Interference

Winter isn’t just about cold temperatures; it also brings with it conditions like frost and ice. Heat pumps are not immune to these icy formations, especially on their coils. 

When ice accumulates, the heat pump’s efficiency can be compromised. To combat this, heat pumps are equipped with a defrost cycle. This cycle temporarily shifts the system into cooling mode, melting away the accumulated ice on the coils

While this is a necessary function to ensure the longevity and efficient operation of the heat pump, it does have a temporary side effect. 

As the defrost cycle runs, the heating function is momentarily paused, which can lead to short-term temperature drops indoors, causing brief discomfort to the inhabitants.

Limited Refrigerant Flow

Refrigerants are the lifeblood of heat pumps. These compounds flow within the system, aiding in the transfer of heat. 

However, their flow properties can be adversely affected by severely cold temperatures. Picture the difference between pouring warm honey and cold honey; the colder it gets, the slower and more viscous it becomes. 

Similarly, as the refrigerant becomes less fluid in extreme cold, its efficiency in transferring heat diminishes. 

This reduced fluidity can impede the heat pump’s ability to efficiently transfer warmth, making it harder to maintain the desired indoor temperatures during cold spells.

Insufficient Insulation

The relationship between a home’s insulation and a heat pump’s efficiency is direct and significant. 

Proper insulation acts as a barrier, minimizing the escape of warmth from inside the house. 

When a home is well-insulated, the heat pump doesn’t have to work as hard, as the warmth it transfers indoors is effectively retained. 

On the other hand, homes with poor insulation present a continuous challenge. Warmth escapes rapidly, and the heat pump has to operate almost incessantly to compensate for this loss. 

This constant operation not only strains the system but also increases the risk of wear and tear, potentially leading to premature breakdowns and increased energy bills.

Old or Worn-Out Components

Every appliance, no matter how advanced or well-maintained, will eventually show signs of wear and tear. Heat pumps are no exception. 

Over time, various components within the heat pump, such as the compressor, coils, or fan, might degrade or wear out. 

As these components age, they might not function at their optimal capacity, leading to a decline in the system’s overall efficiency. This decline is even more pronounced during periods of extreme cold when the heat pump is working its hardest. 

An aging heat pump might struggle to keep up with the heating demands, leading to uneven temperatures throughout the home or longer run times, both of which can increase energy consumption and costs.

Incorrect Sizing of the Heat Pump

The size of the heat pump plays a crucial role in its efficiency and effectiveness. An improperly sized unit can lead to a host of problems. 

For instance, a heat pump that’s too small for the space it’s meant to serve will constantly run, trying to meet the heating demands but often falling short. 

This continuous operation can lead to increased energy bills and undue strain on the system. Conversely, a heat pump that’s too large for the space can lead to frequent on-off cycling. 

This constant starting and stopping can cause wear and tear on the system and might not provide consistent temperatures. 

Ensuring the heat pump is correctly sized during the installation phase can prevent these issues and ensure optimal performance.

External Blockages and Obstructions

The external unit of a heat pump plays a pivotal role in extracting heat from the outside environment. 

However, during winter months, this unit can become obstructed by snow, ice, fallen leaves, or other debris. 

Such obstructions can hinder airflow, reducing the efficiency of heat extraction. In extreme cases, heavy snow or ice can even cause physical damage to the unit. 

It’s essential to regularly inspect the outdoor unit, especially after snowfalls or storms, and clear any obstructions. 

This simple maintenance step can ensure the heat pump operates efficiently and prolongs its lifespan.

Thermostat Malfunctions

The thermostat is the control center of the heating system. It reads the indoor temperature and signals the heat pump to turn on or off accordingly. 

However, if the thermostat malfunctions or gives inaccurate readings, it can cause the heat pump to operate inefficiently. 

For instance, an incorrectly calibrated thermostat might read the indoor temperature as warmer than it actually is, causing the heat pump to turn off prematurely. 

On the other hand, it might read the temperature as colder, causing the heat pump to overwork. 

Regular maintenance and calibration of the thermostat are essential to ensure accurate readings and optimal operation of the heat pump.

Lack of Regular Maintenance

One of the most common reasons for reduced efficiency in heat pumps is the lack of regular maintenance. 

Just like a car needs periodic check-ups to run smoothly, a heat pump requires routine inspections and maintenance. 

These check-ups can identify potential issues, such as dirty filters, worn-out components, or refrigerant leaks, and address them before they escalate into major problems. 

Neglecting regular maintenance can lead to reduced efficiency, increased energy consumption, and even premature breakdowns. 

Especially during the cold months, when the heat pump is under maximum strain, regular maintenance is vital to ensure it operates at its best.

How to Fix Heat Pump Struggles in Cold Weather?

Heat pumps are indispensable for many households, but they can face challenges during the colder months. Let’s delve into some expert solutions to mitigate these issues and ensure your home remains warm and cozy:

Regular Maintenance and Inspection

Routine check-ups are the first line of defense against heat pump issues. By scheduling periodic inspections:

  • Step 1: Engage a licensed HVAC professional for a thorough inspection.
  • Step 2: Ensure they check for worn-out components, refrigerant levels, and electrical connections.
  • Step 3: Address any identified issues promptly to prevent them from escalating.

Proper Sizing During Installation

Choosing the right-sized heat pump is crucial for its efficiency. To ensure this:

  • Step 1: Consult with HVAC experts before making a purchase.
  • Step 2: Allow them to assess the size of your home and its insulation needs.
  • Step 3: Opt for a model that suits your home’s requirements, neither too big nor too small.

Enhancing Home Insulation

A well-insulated home is key to heat pump efficiency. To enhance insulation:

  • Step 1: Identify areas with poor insulation, such as drafty windows or uninsulated attics.
  • Step 2: Invest in quality insulation materials, like spray foam or fiberglass.
  • Step 3: Ensure proper installation to maximize heat retention.

Installing Supplemental Heating

In extremely cold regions, an additional heat source can be beneficial. To implement this:

  • Step 1: Evaluate your home’s heating needs and identify areas where the heat pump may struggle.
  • Step 2: Choose a supplemental heating system, such as electric baseboard heaters or a gas furnace.
  • Step 3: Install the additional system and use it in tandem with the heat pump during the coldest days.

Clearing External Obstructions

Ensuring the outdoor unit is clear of obstructions is vital. To maintain this:

  • Step 1: Periodically inspect the unit for obstructions like snow, leaves, or debris.
  • Step 2: Gently clear away any blockages, ensuring not to damage the unit.
  • Step 3: Consider installing a protective cover or shelter to minimize future obstructions.

Upgrading to Cold Climate Heat Pumps

Advanced heat pumps cater specifically to colder climates. If upgrading:

  • Step 1: Research models designed for cold weather performance.
  • Step 2: Compare features, reviews, and energy ratings to select the best fit.
  • Step 3: Engage a professional for installation to ensure optimal performance.


Navigating the challenges of cold weather with a heat pump doesn’t have to be a daunting task.

By understanding the reasons behind its struggles and implementing expert-recommended solutions, homeowners can ensure a warm and comfortable environment throughout the winter months.

Just as we adapt our wardrobe to the changing seasons, with a bit of insight and care, we can optimize our heat pump’s performance, ensuring our homes remain the cozy sanctuaries we cherish.


Why do heat pumps lose efficiency in extremely cold temperatures?

Heat pumps extract warmth from the outside air to heat homes. In colder temperatures, the available external heat diminishes, making the pump’s task harder and reducing its efficiency.

How does incorrect sizing of a heat pump affect its cold-weather performance?

An improperly sized heat pump can either overwork or underperform. In cold weather, an undersized pump might run continuously without providing adequate heat.

What role does insulation play in a heat pump’s winter performance?

Proper insulation retains indoor heat, reducing the heat pump’s workload. Poorly insulated homes cause the pump to work harder, compensating for the heat loss.

Why is my heat pump’s outdoor unit covered in ice during winter?

Ice forms on the heat pump’s coils in cold weather. This triggers a defrost cycle, where the pump temporarily shifts to cooling mode to melt the ice, affecting heating efficiency.