How do air source heat pumps actually get heat from the air outside and bring it into your home?

We've talked about some of the amazing benefits of heat pumps, but let's take a look at how they actually work! To massively simplify things, air source heat pumps draw in warm air from the outside, put this air through a series of processes which then results in hot water being transported throughout your home- just like in a traditional central boiling system.

You can also get ground source heat pumps, which draw on the energy found in the ground, or in water. For the purposes of this article, we’ll be focusing on air source heat pumps. The general principle is the same, it’s simply the source of heat that changes.

Looking for a more detailed explanation? Then read on.

Getting Started

Take a look at any air source heat pumps and you’ll notice their big fans. These fans draw in the air around them. The cooler it is, the more air they draw in. This air is immediately pulled into a liquid refrigerant. Different pumps may use different refrigerant, but the process stays the same.

This liquid refrigerant will get warm due to the energy in the air, which causes it to become a gas. This gas is then pushed onto the next step in the process.

Under Pressure

The gas is then pushed into a compressor, which takes the gas and puts it under pressure, effectively squishing it! When matter is under pressure like this, it generates more heat. That helps push the temperature up even further, getting the cool refrigerant up to a useful heat level.

With this new hot gas, it’s time to turn all this energy into useable heat. The gas will be moved into heat exchanger, where it will transfer its heat energy into water. From there, the hot water can be transported throughout your home, passing through radiators and water tanks and providing you with warmth as well as hot water!

That means that an air source heat pump can be used as both a hot water heater as well as general central heating.

How Is This Different From Normal Boilers?

The crucial difference between air source heat pumps and other electric or gas heaters for your home is their energy source. Air source heat pumps run entirely off of electricity, and can even be used in conjunction with green energy sources such as solar power.

This means heat pumps are more environmentally friendly and will ensure your home is futureproof for many years to come.

But Wait, What If It’s Cold Outside?

An air source heat pump will be at its most effective when there isn’t a huge discrepancy between the outdoor temperature and your desired indoor temperature, but it can still generate heat even when it’s cold out.

All the air source pumps we currently stock can operate between -25°c and 45°c meaning they’re perfectly equipped to handle the climate in the UK, even at its worst.

It can be a little difficult to get your head around this idea of cold air still having heat in it, so it’s important to remember how heat energy works!

All air has energy in it, which can be used to generate heat. The only possible exception to this is if it reaches a point known as ‘absolute zero’ which is where the temperature is so cold that the molecules that make it up have no energy left.

To qualify as absolute zero the temperature must be -273.15°C, and this temperature has never been recorded anywhere. There’s always a little bit of energy in the air!

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