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How Do Air Source Heat Pumps Work?

If you’re building a new home or making upgrades to an existing one, you might be looking at different options for heating and cooling your space.

There are tons of different options out there, from traditional fossil fuel lines like a gas boiler to new greener technologies like air source heat pumps.

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Heat pumps are becoming an increasingly popular heating system, as people look for central heating that has a smaller environmental impact. We love air source heat pumps for their ease of use, and the way they’re good for the planet.

But what exactly is an air source heat pump? And how do they work? Read on to find out!

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What is an Air Source Heat Pump?

An air source heat pump is a heating and cooling system for homes. They work by absorbing heat in the outside air, drawing it into the system, heating it to your set temperature, and moving the warm air into your space.

When cooling it does this process in reverse, drawing heat out of the air inside the home, and expelling it outside to keep your home cool.

An air source heat pump system is a greener alternative to a traditional boiler or fossil fuel line in a home. Rather than relying on fossil fuels, they can use electricity to easily keep your home at a high or low temperature.

People looking to replace their air conditioning and heating units can turn to technologies like this in their space to keep things green.

Air Source Heat Pump Components

So, what makes up an air source heat pump? While these parts can have slight variations depending on the size of your individual unit or system, and the type of air source heat pump you’ve purchased, all units will typically have these parts:

  • Compressor: The compressor, which is typically outside the home, is responsible for pumping refrigerant through the system.
  • Fan Motor: The system’s fan motor will work to pull air into the refrigerant coils.
  • Refrigerant: The refrigerant is the liquid substance that circulates within the system.
  • Refrigerant Line: These are lines that connect the indoor and outdoor equipment in the system.
  • Coils: The coils within the system are responsible for heating or cooling the air, depending on your set temperature.
  • Indoor Air Handler: This is a unit that can expel hot or cool air from the system into your home.
  • Control Board: A control board or thermostat is used to set the desired temperature.

How Different Air Source Heat Pumps Work

double duty heat pump
Image Credit: Flickr

In order to truly break down how exactly an air heat pump works, we need to explore how different kinds of air heat pump systems function. When shopping for renewable heating air heat pump systems you will likely encounter two kinds: air to air, and air to water.

Let’s take a closer look at what defines these two different systems, and how they work.

Air to Water Heat Pump

An air to water heat pump is a wet central heating system. They work by taking in the heat that exists in the air outdoors and converting it into water.

This water can then be pumped into your home, either via heat radiators in your home or even underfloor heating. They can also be used to provide hot water in your home in general, heating your showers, bath, and water from your taps.

So, what is the benefit of this kind of system? The best thing about it is that it can be used to heat your home, and can function to heat your water.

This means that if you’re trying to build an eco-friendly home, you would only need this one system for both hot water and home heating.

We would recommend this type of system to new home builders, as they do take a fair bit of work to install. They need to be connected to your home radiators, and installing underfloor heating can be a pretty big renovation on an existing home.

These systems are also suited to more moderate climates, not functioning well in cases of extreme heat and cold. This system can struggle to draw in air in below-freezing temperatures.

This can be remedied, though, if you use this system in conjunction with another form of heating, like a hydrogen boiler. This way you can take advantage of your water to air system for the majority of the year, and only have to switch to a boiler in the coldest months.

However, if you’re willing to put up with the construction and costs, these can be a great, efficient, clean way to heat your home.

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Air to Air Heat Pump

The other common heat pump system you will encounter is an air to air heat pump. These systems work by drawing in outside air, pulling it into a compressor.

This compressor can then heat the air to your set temperature, and pump it into your home to keep you warm! This technology can also work in reverse drawing hot air out of your home and pushing it outside to keep you cool.

This is a great option for people who want a system that works for both heating and cooling. As this system moves air throughout the home, it works well when connected to a duct system. However, there are some ductless systems that have wall-mounted units to expel air into certain rooms in your home.

Due to their design, these systems can’t provide underfloor heating or radiator heating like air to water heat pumps.

However, their simplicity does often mean that they are a cheaper option when shopping for heat pump systems.

An air to air system can work well when combined with existing heating and cooling systems. This is something to keep in mind, as these systems are also not suited to extreme temperatures.

The compressor can struggle to draw in and heat up air when dealing with outdoor temperatures below freezing.

These systems also only focus on heating and cooling your home, as they utilise air.

This means you can’t depend on this system for heating your home’s water supply, which can be a downside for some. However, if you already have an adequate hot water system, then air-to-air heat pumps can still be a great addition to your home.

Heat Pump Costs

Many people love heat pump systems because of their efficiency, lack of fossil fuel use, and the money they can save on energy bills. Before you can get started on these benefits, though, you’ll have to consider the costs of purchasing, installing, and running your system. Let’s explore the costs you need to keep in mind as you buy.

Heat Pump Purchasing and Installation Costs

The largest cost will of course be purchasing your system. When you buy a heat pump for your home, you’ll be paying for both the device and the installation costs.

These will differ depending on the kind of system you purchase, the size of your home, the brand of your system, renovations needed for installation, etc. Here, we’re going to provide a general price range for these systems, for an average home.

In an average home for two people, you can expect to pay between £4,000-8,000 for your air to air heat pump unit. Associated installation costs will depend on the kind of unit you are installing. If you are going for a ductless system that simply has an outdoor compressor and indoor air unit, it’s possible that you can handle the installation yourself. However, for units that require difficult installation, the costs for your unit can rise to the £8,000-10,000 range.

The price tag is higher for air to water systems. This is because their installation includes some larger work, like installing an underfloor heating system and connecting your system to your home’s radiators. These systems can cost between £9,000-15,000 for purchasing and installation.

These price tags are shocking, but don’t fret! When shopping for a heat energy system like this, always look at multiple quotes and compare quotes to see if you’re getting the best price. You can also look into different renewable energy incentives, to help you install this green technology into your home. We’ll get into that more in-depth below. 

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Heat Pump Running Costs

Once your system is installed, it’s time to anticipate some changes to your bills!  As these systems utilize electricity, you can expect some drops on your monthly fuel bills, as you cut down on your use of natural gas in your home for space heating. However, this also means your electricity bills will go up.

When it comes to running costs, you can expect to spend around £1,120 annually to run a heat pump in an average-sized home. When compared to using gas systems, you can expect to see savings up to £790-1425 annually on your bills.

These are savings that can add up over time, especially when you factor in the long lifespan of heat pump systems. With one of these systems, you’re saving the environment without having to spend more money. We call that a win.

Heat Pump Maintenance Costs

Of course, no system is perfect. There are a number of things that can happen in life that will mean your system might need some maintenance over time.

The good thing about these systems is that when well installed, they usually require very little maintenance. They also have a longer lifespan than boiler systems, able to service your home for up to 20 years. These systems also often come with warranties, which can save you some costs in the first few years of use.

If you want to ensure your system runs well, you can get a maintenance check done every 2-3 years. These might run you £150-200 per visit.

If you want to avoid maintenance, there are some steps you can take to ensure your system runs smoothly:

  • Regularly check outdoor unit for leaves and debris in the fan and airline
  • Prune any plants or grass around the outdoor unit, keeping it clear
  • Keep system clear of snow and ice during cold weather

Air Source Heat Pump Pros and Cons

heat pump beside house
Image Source: Shutterstock

Let’s take a look at what makes these systems great, as well as some of their drawbacks.

Air Source Heat Pump Pros

There are a lot of things that make these systems great!

Environmentally Friendly

An air source heat pump system is a great way to make your home a green one! These systems can lower your carbon emissions, replacing your use of fossil fuels with electricity to heat and cool your home.

Can Heat and Cool

When investing in an air to air system, they can work to effectively heat and cool down your home. This eliminates the need to pair a heating system with a separate air conditioning system. Now your home’s internal temperature can be easily maintained, all with one unit.

Easy to Install

If you are looking to invest in a heat pump system, air source systems are much easier to install when compared to a ground source heat pump. A ground source heat pump requires construction to install the unit under the ground outside your home. With an air source heat pump, you can install the system without super extensive construction.

Save Money with Incentives

Heat pump systems can be easy to invest in thanks to different Government incentives that work to make UK homes more environmentally friendly. Renewable heat incentives like the Domestic Renewable Heat Incentive, Non-domestic Renewable Heat Incentive, and the Green Deal are helping homeowners manage the costs of investing in these systems.

Air Source Heat Pump Cons

Here are some of the downsides to owning and operating an air source heat pump:

Not Good in Extreme Climates

These units are good at heating and cooling homes, but work best in places with more moderate climates. If you live somewhere that can reach temperatures below freezing, they can struggle to adequately heat up a home.

Need Outdoor Space

An air source heat pump does require space outside the home to house the condenser unit. These can be comparable to air conditioning units in size, which can be an issue for some homeowners if they don’t have the outdoor space.

Not Zero Carbon

While these units do cut down on carbon emissions, they’re not inherently zero carbon. Their reliance on electricity can mean you’re still contributing to carbon emissions depending on the energy source for your home. (However, this can be combated if you make the energy source something renewable like solar panels or wind energy.)

Air Source Heat Pump FAQ

Do you still have questions? Here are some common things people ask when it comes to these units.

Can I install an air heat pump myself?

Depending on the type of unit and your skill level, you can install these units by yourself. Some smaller air to air heat pump systems that don’t require duct connections can be easy enough for people to install.

However, to ensure your system has long longevity, we recommend getting a professional to install your system.

Can I claim a renewable heat incentive when buying a heat pump?

If you are a home or business owner in the UK, there are different renewable heat incentives you can claim when buying a heat pump. We recommend looking into the Domestic Renewable Heat Incentive, Non-domestic Renewable Heat Incentive, and Green Deal

Will an air source heat pump save me money?

An air source heat pump can save you some money annually, when compared to traditional forms of energy. These systems draw on electricity, cutting down on your gas bill. While this can cause a rise in your electricity bill, it can still save you money over time.

The best way to save money with an air source heat pump is to power it through green energy like captured solar power or wind turbine energy. If you can outfit your home in this way, the savings become even more significant.

Are air source heat pumps better than ground source heat pumps?

Neither of these systems is necessarily better than the other. It all comes down to the one that suits your home needs best! Air source heat pumps can be great for individuals with smaller homes, or those who want a cheaper, easy-to-install unit. Ground source heat pumps can be pricier and are better suited for larger homes and businesses.

Are there alternatives to air source heat pumps?

If you are unsure about using an air source heat pump, there are always other options to consider. We recommend looking into boiler systems if you want to find a good system to effectively heat your home. We especially love hydrogen boilers, as an eco-friendly alternative to traditional gas boilers.

Remember, when shopping for any system, it’s useful to compare quotes! You can always use us to compare boiler quotes, to ensure you’re getting the best system possible.

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