How Does An Air Source Heat Pump Work In Cold Climates?

Many people believe that the one downfall of air source heating technology is that heat pumps struggle in cold climates, and that they work best when the weather is a little warmer.

This is actually something of a myth.

Yes, if the air outside is already warm, the heat pump doesn’t have to work as hard to convert it. This doesn’t mean that an air source heat pump should not be an option for you if you live somewhere cold. In fact, we’d say that it’s just what you need!

Air source technology answers to the same British heating standards that traditional fossil fuel sources do, and they perform just as well in whatever climate, so you’ve got nothing to worry about.

Here’s how a heat pump works in our cold and miserable British weather.

Air source heat pumps for heating

To understand just how an air source heat pump functions in cold weather, it helps if you know how the technology works overall. Here’s a quick explainer:

Think about how your refrigerator works. Those coils you might have noticed at the back of your fridge expel heat from within the fridge; and with an accompanying coolant system, your food and beverages stay cool and fresh. The coils transfer warmth from the enclosed space (your fridge) so that all that is left in your fridge is cool air.

So, what does this have to do with an air source heat pump? They work on the same premise, but in reverse.

Instead of absorbing heat from within your home (or your fridge) and expelling it outward, an air source heat pump absorbs heat from the outdoor environment and uses it to steadily warm your home.

Then, once the heat energy from outside is absorbed, the heat pump’s compressor converts the gas into a hot liquid which travels to your indoor system, where your blower helps to release the heat into your duct system. It all sounds very technical, we know! If you have any questions, they’re answered here (and if not, give us a call on 0333 733 1703).

What about when it’s cold out?

Many are led to think that cold weather means there can be no ‘warm air’ for an air source heat pump to absorb. It seems to make sense, right? Actually, a heat pump will still work in temperatures as low as -15°C: a temperature which the average UK town will rarely reach (despite how cold it might feel).

What about when it’s *really* cold out?

Because air source heating technology is incredibly smart, a heat pump has an in-built defence mechanism against extremely cold temperatures (i.e. below freezing).

A heat pump has what is called a defrost cycle that protects it from ice and frost. Quite ingeniously, the defrost cycle pumps some of the hot liquid (converted from outdoor air) back into the heat pump so that it defrosts the whole system.

You’ll know when an air source heat pump is going through its defrost cycle because the whole thing will apparently stop working and steam will rise. It’s not broken, so don’t panic! What happens is that the external fan will stop absorbing outdoor air, so that the internal heat pump system can warm itself. This takes around 15 minutes to complete.

A wintertime maintenance checklist

So that’s how an air source heat pump protects itself! They work in extremely cold temperatures, and while some may say that they’re more efficient in warmer weather, you can rest assured that this groundbreaking piece of technology has you covered.

Come wintertime, there are a few small measures that you should take to ensure your heat pump works as effectively as ever. Here they are:

  • Arrange to have your system serviced once a year. We can sort that for you!
  • Every now and then (we’d say once every fortnight) check your air pump unit and clear away any debris like dirt, snow, or leaves.
  • Don’t stack anything on the unit. They’re very sturdy, but putting things on top may affect its performance (this goes for the rest of the year, too).
  • If you want increased protection from the elements, you can use an awning to cover the heat pump. It’s by no means necessary, but it may put your mind at rest!

Remember, you’re covered for temperatures as low as -15°C

This is extremely cold, and we are unlikely to reach such freezing temperatures in the UK. If you’d like to know more about air source heat pumps and your property, take a look at our in-depth guide.

If you have any other questions at all, you can reach us via our quick and painless enquiry form.

Dec 04 2018