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The Most Useful Guide to 5 Heat Pump Issues in Cold Weather

Views: 330     Author: Site Editor     Publish Time: 2022-12-15      Origin: Site

How frustrating it is to have a problem with your heat pump in the cold winter.

Imagine it's a busy and tiring work day; it's snowing in your place; the biting wind is blowing on you, and you can't help but wrap up your coat and speed home, wanting to get into your warm and comfortable home in a minute. You open the door and turn on your heat pump, but for a long time, nothing happens.

Just like any equipment in your home, heat pumps can have some problems from time to time, especially in the cold winter months, and it is quite normal.  

Thus, it is necessary to know some basic heat pump troubleshooting methods, and by eliminating them one by one, we can reduce the trouble of calling professionals. Of course, when in doubt or you can't solve the problem yourself, feel free to contact a professional heat pump company like SPRSUN.

So, what common problems are likely to occur with heat pumps in the cold winter months? The following is a listing of common problems.

  1.  Covered with ice

  2.  Clogged coils

  3.  The outdoor heat pump unit is not  working or running poorly.

  4.  Drainage problems

  5.  Cold air from fans


It is of note that the efficiency of a heat pump decreases as the outdoor temperature decreases. A heat pump's efficiency is expressed in terms of COP. Here is a popular blog explaining a Good COP for an Air to Water Heat Pump.

A heat pump's  efficiency declines sharply when the outdoor temperature drops to 5 degrees Celsius and below. But at what temperature does a heat pump stop working? The answer is never because heat pumps never stop working.

Heat pumps will do their best to work even in extremely cold weather. That's why heat pumps are most commonly used in milder areas. Boilers or furnaces are often used in places with very cold winters. Of course, some people also choose hybrid heating systems. In addition to that, many cold climates heat pumps are now available through some breakthroughs in heat pump technology. These heat pumps are specifically designed for extremely cold weather, which can operate efficiently even in weather conditions below -25 degrees Celsius, providing enough hot water and ensuring the warmth and cosiness of your home.

9.5KW R32 ERP A+++ Small Cold Climate DC Inverter Monoblock Heat Pumps

Now, let's look at some of the commonly-seen problems with heat pumps in cold climates and what phenomena accompany these problems. Together let's analyze the possible causes and corresponding measures so that you can draw on them when encountering similar problems.

1.  Covered with ice

It is common and normal for the coils of a heat pump to become covered in frost during cold weather. Usually, there is frost on the heat pump between defrost cycles because the liquid refrigerant gets frozen as it flows through the coils, thus forming frost. However, the frost may gradually build up and form solid ice if your heat pump system is not working properly. The ice impedes airflow and hinders the heat absorption. It is abnormal for a heat pump to be covered with large amounts of ice.

Usually, heat pumps have defrosters that can melt the ice that forms on top of the heat pump and help solve the problem. But if the defroster cannot solve the problem either, you should call your heat pump specialist to have your system repaired.

1. Clogged coils

Clogged coils are another thing to watch out for in the cold weather. Coil clogging may occur when the liquid refrigerant starts to freeze. The final result is that the coils freeze, the system does not work properly and eventually shuts down. When you have clogged coils, it is important to check every vent in your home to see if there are any obstructions above the vents. Any obstructions can disturb the airflow to the heat pump and cause solid ice to accumulate during the winter months.

2. The outdoor unit is not working or running poorly.

If your heat pump is not doing a good job, excluding the problem of being covered with ice, the cause could be a faulty heat pump unit component:

A: Troubleshoot the power supply.

Disconnect the power switch and check the power supply.

B: Check whether the unit’s power supply wiring is loose.

C: Check whether the unit control power fuse is broken, identify the cause and repair it or replace it with a new fuse if necessary.

In addition, check the air filter to see if it is dirty or clogged. If you have a clogged filter, you might need to replace it to improve the heating capacity. Suppose the heat pump still can not operate after these measures. You may have to contact a heat pump specialist to assist you, as there may be problems with the heat pump’s other parts.

3. Drainage problems

One of the various heat pump problems during winter is drainage issue. Sometimes, if a heat pump starts to freeze, it may lead to a complete system shutdown. This means the liquid refrigerant no longer flows through the frozen heat pump coils. If you can't troubleshoot this soon enough, you may need to have it checked out by a specialist, which could be a big expense!

There are three ways to avoid drainage problems.

A: Make sure you remove any drain plugs that are not in use

B: Use a gas heater or electric heater as a backup when using a heat pump

C: Keep all vents throughout the house free of blockages or other obstructions.


4. Cold air coming out of the fan

Assuming that your house is still cold, even if you use a heat pump, you should check your thermostat settings first. You may have accidentally turned on the air conditioning mode. If you sense cold air coming through your fan and there is no temperature change throughout your house, your heat pump may try to maintain the current temperature.

Suppose you adjust the thermostat to you desired temperature. Your heat pump will run hard to reach that temperature. However, the actual temperature may be several degrees lower than the target temperature due to reduced efficiency in cold weather, even if the system has been operating long enough.

For someone sensitive to changes in temperature, a few degrees can greatly affect their comfort. This is when you may need to contact a professional heat pump specialist to deal with it. Of course, here is a tip, you can set the thermostat a few degrees higher than the ideal temperature. In this case, the heat pump will work hard to reach your set temperature. Although it is impossible to reach the set temperature, the temperature the heat pump can reach and your ideal temperature will be quite close.

In addition, many factors can cause a heat pump to underheat. For instance, if your home is not sufficiently insulated, so much heat is lost from the walls and roof, making it difficult to achieve good heating or cooling effects. For this, you need to reinforce the insulation of your home. Inadequate heat pump refrigerant can also affect the heat pump heating. This is when you need to contact a heat pump expert to recharge the refrigerant in the unit. Then there are cases where the heat pump you choose is too small, or your heat pump is ageing, etc., and it cannot provide enough heat to your house. In that case, you need to consider a larger heat pump, gas heater, or electric heater as a backup.


In the harsh winters, an ordinary heat pump is unlikely to run as perfectly as you might expect. It's not a mechanical failure or malfunction. You can use an alternate auxiliary heating method, such as a gas or electric heater. To cope with the cold, you can also choose  SPRSUN EVI low-temperature heat pumps, which operate efficiently even at -30°C and features ERP A+++ energy rating, low-noise operation, R32 refrigerant, and intelligent defrosting.

However, if the heat pump is not working properly and troubleshooting one by one does not solve the problem, you will have to contact an HVAC technician to find the root cause of the problem and fix it.

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