Recent weather fluctuations may have increased the risk of the air source heat pump freezing.

Freezing, on the other hand, can, at worst, paralyze the entire heating system if the propeller of the outdoor unit cannot rotate or is left blocking ventilation.

Rapid temperature changes from zero degrees to pouring frosts increase the risk of the air source heat pump outdoor unit freezing.

Likewise, the risk is higher than usual in a snowstorm.

Both weather phenomena have been seen in abundance this winter.

Occasionally, frost frosts can also freeze the pump.

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Jussi Hirvonen, Executive Director of the Finnish Heat Pump Association Sulpu, has decades of experience in defrosting the outdoor unit of an air source heat pump.

He also has a clear vision of how the pump should be defrosted and what should not be done under any circumstances.

- Under no circumstances should ice be broken with brute force.

If the ice starts to break loose, at worst, the whole outdoor unit will break down and you will have to get a new one.

It may cause leaks in the outdoor unit of the pump, and even the slightest damage to the pump will be ugly surface damage, Hirvonen emphasizes.

A new outdoor unit usually costs between 500 and 800 euros.

Instead of breaking the ice, the ice should be thawed, and hot water is best for thawing.

- Melting with hot water is more energy efficient than melting ice with hot air.

In practice, the defrosting process begins with the pump being switched off.

According to Hirvonen, it is enough to turn off the pump with the remote control, but if you want to play it safe, you can unplug the device.


 Under no circumstances should ice be broken with brute force.

When the air source heat pump is switched off, hot water is placed in the watering can.

- Sprinkle it on the grate until it and the bottom are free of ice.

Then look at the louvers so that there is no ice around the fan, for example.

You need to put so much water that the ice is gone.

After defrosting, it is advisable to start the pump as soon as possible so that the water used for defrosting does not have time to freeze again.

- If you want to make the drying of the unit more efficient, you can put the pump to cooling for a while.

Let’s talk about that for a few tens of minutes.

With the cooling setting, the cell heats up and removes all moisture.

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According to Hirvonen, freezing is rare in current pumps, but in front of every pump owner at least once.

Many types of weather can lead to freezing, but on the other hand, winter weather does not automatically lead to it.

Hirvonen's own pumps do not freeze every winter or even every other winter.

Some of his pumps have survived for years without freezing.

In most cases, the pump in a small sauna room freezes.

Hirvonen digests it approximately every 3-4 years.

The freezing of the air source heat pump is facilitated by an outdoor unit installed too low.

- The probability of freezing can also be increased by the size of the space to be heated.

If the space to be heated is very small and the air source heat pump is unnecessarily large, it may freeze more easily.

In addition, cottages that are kept at a temperature of about 10 degrees in winter are at risk.



 Once the ice has not melted, it tends to accumulate and accumulate.

Technically, freezing is due to the pump not having time or being able to melt all the ice or snow.

Antifreeze resistors and cables prevent freezing, but they do not completely prevent freezing either.

- Freezing is due to the pump not melting the ice completely.

There will be long ice left somewhere in the corner or bottom.

Once the ice has not melted, it tends to accumulate and accumulate.

At some point, this accumulation of ice will then begin to interfere with the operation of the pump.

According to Hirvonen, the responsible pump owner regularly inspects his outdoor unit.

The faster the ice has melted, the less time it has accumulated.