Air Source Heat Pumps: What They Are and Why You Need One

An Air Source Heat Pump (ASHP) extracts the heat from the air outside a property, using it to provide heat inside the property, heating radiators, underfloor heating systems or warm air convectors. It can even be used to provide hot water.

Many people think that in the often cold climate in the UK that Heat Pumps simply won’t work, there not being enough heat in the air to use in the first place. This is not the case though as ASHPs can extract heat from the air even when the temperature is as low as -25°C.

They are not to be confused with ground source heat pumps, which captures the heat stored in the ground and uses this to warm a property. These ground source pumps are much harder to install as they require extensive ground works and thus cost a lot more.

Another advantage of an ASHP is that, depending on the model, they can operate both as air conditioners and as furnaces/heaters, depending on what you want at any given time. You can switch between heating and cooling quickly and efficiently if you are using certain types of ASHPs. Let’s take a closer look at what air source heat pumps are, how they work, and why you should install one in your home!

What is an Air Source Heat Pump?

An air-source heat pump, as we’ve already discussed, transfers heat from a cold space to a warm one using some relatively simple equipment and basic physics. It does this through a process called “reverse cycle operation.” Air source heat pumps take advantage of the latent heat that is in the air around us, transferring it from the air outside a home to the air inside the home using an evaporator, some gas, a compressor and a plate heat exchanger.

Some Air source heat pumps, can also be used as an air conditioning unit, cooling the air inside your home by reversing the process outlined above.

They are able to do this by reversing the normal flow of refrigerant through the system. This means that during the summer, the heat pump will draw the warm air inside your home, transfer the heat to the outside air, and then pump the now cooled air back inside.

During winter, the process is reversed. The heat pump transfers the heat in the outside air to the air in your home.

Why should you install an Air Source Heat Pump?

Air source heat pumps are a great investment that will keep your home comfortable year-round. They are able to provide heating and cooling solutions both quickly and efficiently, allowing you to save money on your utility bills! Air source heat pumps provide the best heating and cooling solutions during the months when your homes need it the most – those nasty, cold winter nights and scorching hot summer days. They are able to take advantage of the outside air temperature and quickly transfer heat from the cold, outside air to the warm inside air. 

How much do Air Source Heat Pumps cost?

Like most things, the price of an air source heat pump will vary depending on the size of the unit, the brand, and the features that particular unit offers. You can expect to pay somewhere between £2,500 and £20,000 for an air source heat pump, with the average price being approximately £6,500. When choosing the right heat pump for your home, be sure to take into account the size of your home, the amount of insulation you have, how many people live in your home, and what you need the heat pump for – heating or cooling.

What to be aware of when buying an air source heat pump?

It’s important to be aware that not all heat pumps are created equally. Some heat pumps are designed for cooling, some for heating, and some for both. Just remember, if you select a heat pump that is designed for both cooling and heating, it won’t be as efficient at either task. Why is that?

Well, the heating and cooling functions of an air source heat pump work in opposing ways. During the winter, the heat pump uses the outside air to cool the inside air and provide warmth. During the summer, it uses the inside air to cool the outside air and provide cooling. While this might not be an issue in mild climates, it can create inefficient results in areas where temperatures fluctuate greatly.


Air source heat pumps are a great investment that will keep your home comfortable year-round. They are able to provide heating and cooling solutions both quickly and efficiently, as long as the climate in your location falls within certain guidelines.

Also, don’t think you will stop using electricity entirely. Yes, your utility bills will be lower, but ASHP’s do need electricity to drive the fans and compressors that make them work, just don’t expect your bills to reduce to zero.

The best advice is to take advice from a specialist heat pump engineer firm like Spartamech. They can answer all your questions and recommend the right model for your home.

Sarah Evans