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Air to Water Heat Pumps

Homeowners are switching to air to water heat pumps in their droves. By using the free air from outside, heat pumps are a great home heating method to drastically reduce energy bills and household carbon emissions. 

But how do they really work, and how are they installed?

How much can I save?
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Two Aira heat pump installers with an air to water Vaillant heat pump

What is an air to water heat pump?

An air to water heat pump is a central heating system that combines energy from the outside air with electricity to heat water, which travels through your existing network of radiators and underfloor heating to keep your home warm.

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How does an air to water heat pump really work?

The heat pump, which sits snugly alongside your home, draws in the surrounding air using a fan and extracts heat from it. This heat transfers into your pump’s refrigerant, and a compressor increases the temperature of it.

From here, the heated refrigerant enters a heat exchanger, giving the extracted energy to the heating system. 

Finally, the heated water cycles through your home’s heating system, and once it is used and cooled, the now-cold water returns to the heat pump to begin the process again. 

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Get £7,500 off an air to water heat pump with the Boiler Upgrade Scheme

The Boiler Upgrade Scheme (BUS) is a grant provided by the British government to incentivise people to make the eco-friendly switch from a fossil fuel or oil boiler to a low-carbon heat pump. 

Customers in England and Wales will get £7,500 taken off your quote, whilst we can advise customers in Scotland to get the most of the grants available to you.

Boiler Upgrade Scheme

See what you can save

Use our calculator and find out

An air to water heat pump can work with your existing central heating system

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How do air to water heat pumps work with radiators?

Just like with a traditional boiler system, an air to water heat pump works alongside radiators by pumping the hot water into the radiators to keep your home cosy. 

Unlike boilers, air to water heat pumps provide up to 400% efficiency (which is great for your pocket) and can be powered with fossil free electricity (which is great for the environment).

Person with a drill preparing to install a radiator which is on the floor in front of them

Would I need to change any of my radiators when I install an air to water heat pump?

Radiators with a large surface area help to get the best efficiency from your heat pump. The larger surface area allows the heat pump to run at lower temperatures, keeping your house cosy and energy bills down.

If you have older or smaller radiators, this may mean upgrading some of your radiators. But don't worry we will let you know if any radiators need changing during your survey, and you'll hardly spot the difference.

Outside of a house with an air to water heat pump

How do air to water heat pumps work with underfloor heating?

The only difference you’ll notice when you switch to using a heat pump for your underfloor heating is lower energy bills. Underfloor heating uses radiant heat transfer to warm your home. Just as usual, the network of pipes under your home releases heat from the hot water generated by your air to water heat pump, providing an even and comfortable warmth.

Best of all, because underfloor heating uses a larger surface area, the water temperature doesn’t need to be as hot – meaning air source heat pumps and underfloor heating combined are a beautifully efficient match. 

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Aira employee showing two customers something on a tablet

I’m so happy with my heat pump. It's so much more efficient than my boiler. The Aira team were excellent and kept me informed every step of the way. I’m looking forward to a cosy heat pump winter!

Chloe S, London

Our Clean Energy-Tech

Vaillant air to water heat pump against a white wall

Heat pumps

Air source heat pumps slash your CO₂ emissions by 75%, and shrink your heating costs too.

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3 of Vaillant's range of aroTHERM air to water heat pumps against a grey background

Vaillant air to water heat pumps

When you’re ready to switch to lower energy bills and an efficient carbon-light home, switching to aroTHERM plus air to water heat pumps is the gold standard in renewable home energy.

Not only do Vaillant offer a variety of sizes to suit your home – 5, 7, 10, 12 and 15kW – but installation takes a mere 4 days and is included in the cost when you switch with Aira.

And homeowners won’t have to worry about the unexpected going wrong – Aira offers a Comfort Guarantee including necessary parts, servicing and maintenance.

Why Vaillant's range of air to water heat pumps

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A+++

The highest possible energy class rating

A+++
The highest possible energy class rating
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Natural refrigerant

R290, the eco-friendly choice

Natural refrigerant
R290, the eco-friendly choice
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App-controlled

Control your heat pump from anywhere

App-controlled
Control your heat pump from anywhere
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Compact design

Ideal for small spaces

Compact design
Ideal for small spaces
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Quiet Mark awarded

Hear that? It’s your near-silent heat pump

Quiet Mark awarded
Hear that? It’s your near-silent heat pump
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Advanced technology

Optimal heating and hot water performance

Advanced technology
Optimal heating and hot water performance

The Aira all-inclusive experience

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Lower costs, less carbon

25% lower heating costs, 75% less carbon emissions

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£7,500 grant and 0% VAT

Let the government help cover the cost of your heat pump

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Hassle-Free Switching

Installed within 4 weeks with 10 years service & maintenance

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Comfort Guaranteed

Guaranteed cosiness on even the coldest day of the year

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What does an air to water heat pump installation look like?

There are a few components to correctly installing an air-to-water heat pump as you’d expect. With Aira, the installation is included in the cost, and likely won’t take as long as you think.

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Installing the outdoor unit

The heat pump has an outdoor unit that sits snugly alongside your home and looks like a classic air conditioning unit. The exact location for your heat pump is selected by specialists who optimise for heat intake and efficiency. 

At the heart of your outdoor unit is the compressor, a powerhouse that begins the process of converting the free air from outside into useful heat. The compressor compresses the refrigerant, raising its temperature. The hot refrigerant then heats water, which is pumped through your central heating by the indoor unit.

Heat pump installers from Aira finishing the installation of a hot water tank for an air to water heat pump and programming a thermostat

Installing the indoor unit

Your heat pump’s indoor unit is then installed inside your home. The most common style of indoor unit used in the UK is called a hydraulic station. It’s about the same size and shape as a boiler and is often tucked away in your utility closet. This indoor unit distributes the heated water from the outdoor heat pump into the heating system and hot water cylinder.

The alternative is an all-in-one unit. This is larger, being a similar size to a refrigerator, but does not require a hot water cylinder. During installation, this indoor unit will be connected to your underfloor heating system or radiators, and expertly set up to maximise your heat pump’s efficiency and keep you cosy all year round. 

Vaillant uniSTOR hot water cylinder installed by Aira

Installing the hot water cylinder

During your initial survey, your Clean Energy Expert will work out how much water the household uses, as well as potential locations for the cylinder, so that the correct size can be chosen to ensure you always have hot water ready. 

Your hot water cylinder will then be installed and linked to the rest of your plumbing, allowing the hot water generated by your heat pump to evenly reach and heat every part of your home through your existing network of pipes, taps, showers and radiators.

What an Aira air to water heat pump installation looks like

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25%

Reduce your heating costs by 25%

15-20

Heat pumps have a longer lifespan of 15 to 20 years compared to a boiler's 10 to 15 years

100%

We guarantee that you are 100% cost all year round with the Aira Comfort Guarantee

Air to water heat pump FAQs

Heat pumps can provide effective heating in temperatures as low as -25 degrees celsius. And because your package includes our Aira Comfort Guarantee at no extra cost, you’re guaranteed 20 degree celsius cosiness on even the coldest day of the year – or we’ll come straight out to fix it.

We'll ask some initial questions to check your home is suitable for a heat pump (70% of homes are). We will then help you claim this grant through the Boiler Upgrade Scheme and guide you through the application. We will provide all the support and information you'd need from the initial application to the day of the installation.

In order to install a heat pump, you should own your property (or have permission from your landlord), have outdoor space to store the unit, and have a reliable electricity supply.
During our quick call with you, we will find out if your home is already heat pump ready. We will discuss various aspects of your property, such as the size of your home and when it was built.

Installation of your air to water heat pump is usually complete in under four days. If we think your installation might take longer, we will let you know.

After switching to a heat pump, you will have the same hot water temperature in your home as before.

Let’s talk energy efficiency

Want a no-strings chat about improving your home’s energy efficiency? Share your contact details with us and we'll call you back.

Or call us on: 0330 822 5493

Weekdays Monday to Friday 9am - 6pm

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