Air Source Heat Pumps
Everything You Need to Know
A sustainable, efficient heating solution from reliable air source heat pump experts.
Heat pumps keep you warm, not the planet.
As fossil fuels get phased out across all elements of the energy market and gas boilers face looming bans, heat pumps remain one of the most efficient ways of heating your home sustainably with minimal maintenance.
You may have questions about what they are, how they work, and how much they cost to install and run. To make it super easy, we’ve covered it all in this ultimate guide.
- What is an air source heat pump?
- How do air source heat pumps work?
- The benefits of an air source heat pump
- Helping the environment
- Different types of heat pump
- Will I need to upgrade my radiators?
- Gas boiler vs heat pump
- Is an air source heat pump right for me?
- How much does an air source heat pump cost?
- How loud is an air source heat pump?
- How much does an air source heat pump cost?
- Average air source heat pump installation costs
- Spread the cost into manageable monthly repayments
- Will a heat pump save me money on my energy bills?
What is an air source heat pump?
Air source heat pumps (ASHP’s) are an innovative, efficient, renewable energy system that will heat your home and your hot water using energy from the air outside your home even in the depths of winter.
Air Source Heat Pump systems are highly energy efficient compared to traditional gas boilers and could save you money on your energy bills. They are quiet, easy to use, and don’t need much maintenance once installed.
Finally, they are environmentally friendly and do not rely on fossil fuels so also help contribute towards a sustainable future and the journey to Net Zero.
How do they work?
Air source heat pumps do not generate electricity, they just use it more efficiently. They work by absorbing energy from the air outside and converting it to heat your home even in temperatures below freezing.
Energy is never created or lost, it’s simply moved. When you heat your home using something like a wood burner, fireplace, or gas/oil boiler, you’re relying on the energy stored in those materials for the heat. Your heat pump has a finite source of energy – it works like this:
- Refrigerant Circulation: Refrigerant circulates through an evaporator.
- Air Intake: A fan draws outside air over the evaporator, absorbing energy.
- Vaporisation: Absorbed energy causes the refrigerant to vaporise.
- Compression: Vapourised refrigerant is compressed, generating heat.
- Heat Exchange: Hot vapour passes through a condenser, transferring heat to your home’s water-based heating system, heating your hot water and radiators.
- Cooling and Expansion: Refrigerant, still under pressure; is cooled and then expanded, restarting the cycle.
Will an air source heat pump heat my hot water?
Yes! Your new air source heat pump will heat your water to the right temperature just as well as your previous heating system. You will need to have a water tank as part of the system and this will be taken into account in your system design.
The benefits of an air source heat pump
Air Source Heat Pumps offer significant benefits compared to traditional methods of heating water and homes. Here are some key advantages:
Save Energy
An air source heat pump is up to 300% more efficient than a traditional boiler.
Reduce Carbon
Heat pumps reduce your homes carbon footprint by up to 73% when compared to gas.
Less Hassle
They are quiet, easy to use, and rarely need any further maintenance, once installed.
Helping the environment
Traditional heating methods like wood burners or gas boilers release stored energy through combustion, which contributes to climate change. Heat pumps avoid this by simply moving heat from one place to another.
Put simply, a tree grows by capturing energy from the sun and absorbing carbon from its environment. That energy gets stored in the wood until it is cut down and used for firewood. If that tree grew millions (or billions) of years ago and fell in the right conditions, that stored energy could have condensed even further into coal, crude oil, or natural gas. So these forms of heating work by releasing that stored energy through combustion.
As we’re seeing with the accelerating rate of climate change, releasing so much of that energy stored in wood, coal, gas, and oil is creating real problems for environments around the world. Heat pumps, on the other hand, don’t need to combust anything as they’re not a source of energy in themselves but simply move energy from one place to another.
In summary, your air source heat pump is an environmentally friendly way to heat your home whilst also helping you on your journey to Net Zero.
Different types of heat pumps
There are three main types of heat pumps, which can extract heat from air, water, and ground, each with their own pros and cons. The different methods of tapping into them essentially make them better suited to different geologies and climates. For the UK climate and most UK properties, air source heat pumps are the most effective option.
Ground Source Heat Pumps
Ground source heat pumps work by burying a pipe in the ground, either through a number of really deep boreholes (sometimes up to 150m deep!) or through a “slinky” pipe that’s coiled around a relatively shallow ditch which is then in-filled. These pipes draw heat from the soil in which they are buried.
This type of heat pump is generally more expensive to install and run.
Water Source Heat Pumps
Rather than running a pipe loop through soil, water source heat pumps drill down into an aquifer to access underground water sources (though sometimes, a nearby river or water source is used).
The method of extracting energy is the same: run a water/antifreeze mixture through the pipe loop, warm it up from the water source, extract that heat through a heat exchanger.
Air Source Heat Pumps
Air source heat pumps, at first glance, feel like they shouldn’t be as effective and consistent as ground or water source pumps but they’re the most reliable, and cost-effective solutions (in certain climates).
A loop filled with refrigerant is snaked around the back of the heat pump unit like a car radiator; this is the “evaporator”. A fan pulls air over the evaporator loop so the refrigerant can extract the air’s energy and turn the liquid refrigerant into a vapour.
Will I need to upgrade my radiators?
Air-to-water heat pumps replace a boiler in order to provide heat for hot water and central heating. They’re really efficient but operate at a slightly lower maximum output compared to fuel-burning systems – so you may need to upgrade to bigger radiators for maximum efficiency.
That said, this is only essential if your radiators are old-fashioned single-panel models. Most radiators installed in UK homes in the last 20-30 years will work perfectly well with an air source heat pump. The only drawback of an air source heat pump installation with old radiators is that system efficiency will be reduced. So it doesn’t have to be all or nothing – you can get a heat pump installed and then opt to upgrade your radiators a few years down the line!
If we feel that your system would benefit from upgraded radiators, we’ll let you know, but it certainly doesn’t stop you from making the jump to clean energy.
Gas boiler vs heat pump:
which is best?
In the UK, we have a love-hate relationship with gas boilers. They’re fast and powerful, but they also have to use a lot of fuel to operate. What’s more, the fact that they have to use a fuel limits their efficiency: they can only ever be 100% efficient.
Operating at 100% is also only a theoretical possibility – all fuel-burning heaters lose energy in some form or another, so usually operate between 60-95% efficiency. This, in turn, means that between 5-40% of fuel used for heating is wasted.
Boilers don’t just waste money through inefficiency but burning these fuels is creating serious problems with emissions leading to accelerating climate change around the world. Moreover, they’re finite. Experts estimate that the world has around 50 years left of oil and gas at the current rate of consumption.
Fuel-based boilers also need consistent access to that fuel which means you either need to have a mains connection or are forced to install bulky, hazardous fuel (like an LPG or oil tank) somewhere near your home.
Heat pumps, on the other hand, draw heat from the outside air and, crucially, can be powered entirely by solar photovoltaic electricity or from 100% green grid-energy tariffs – so you can get dependable, sustainable energy all year round!
Is an air source heat pump right for me?
Whether upgrading to an air source heat pump is right for you or not depends on a few things
Where you live
While we rarely have blazing hot summers in the UK, we also rarely have bitterly cold winters. An air source heat pump is therefore perfect for almost everywhere in the UK because it can work off-grid and still operate when outside temperatures are as low as -28°C.
The size of space that needs to be heated
Heat pumps have a slightly lower maximum output than fuel-burning heating systems. This helps to make them incredibly efficient and compact for most UK properties but sometimes requires more technical expertise to effectively size a system for large buildings (like offices, large homes, or municipal buildings). A well-designed and installed system will ensure that you are making the most of the efficiencies that your Air Source Heat Pump offers.
Space for installation
You’ll need to have space for the heat pump unit to be installed outside of your home – so this may be more difficult or impossible if you live in an apartment building. But there is a lot of freedom over where we can put the unit if you have space. You will also need space for a hot water tank.
As above, a well-designed and installed system will take all of this into account so you get the most out if your new Air Source Heat Pump.
Current heating system
Because most UK homes are currently heated through gas boilers and water-based radiators, an air-source heat pump is a perfect alternative for sustainable heating.
If your home is currently heated through air ducting, then an air-to-water heat pump may be a costly transition, but an air-to-air heat pump could be right for you. However, this isn’t usually a concern for most UK domestic properties.
For almost all UK applications, air source heat pumps require minimal maintenance, are straightforward to install, and can operate completely sustainably from greenly sourced electricity. We also love a challenge – so if you’re unsure whether air source heating is right for your needs, use the contact form below or give us a call and we can assess what’s possible!
How loud is an air source heat pump?
We go into heat pump noise here in more detail but essentially, heat pumps aren’t loud for two reasons:
- Modern designs have dramatically minimised noise.
- You’re rarely standing next to the unit.
The heat pump units we choose for our installations are all chosen with noise output as a key factor – the quieter the better. Most models have a “Standard Sound Mode” during day-to-day, normal operation, which makes the outdoor unit incredibly quiet.
At 3 metres, the sound pressure is often around 38 dBA, which is about the same as the sound of leaves swaying in the wind or the gentle hush of a library.
In fact, the Ideal units we supply hold the UK Quiet Mark certification for being among the quietest available.
So air source heat pumps are remarkably quiet, but sound pressure also becomes exponentially weaker with distance – and such the sound of an ASHP doesn’t get through walls and windows. Even in commercial applications where suppressing noise is crucial (such as heating recording and media studios), the noise of the outside unit isn’t a consideration. What’s more, water-based heating systems are certainly quieter than HVAC systems inside a property because there aren’t any fans running to blow air around the building.
How much does an air source heat pump cost?
As with many significant investments in your home, establishing the actual cost of an air source heat pump isn’t as simple as adding and subtracting. It’s also not easy, to give a specific set of numbers as each system is bespoke to the property that it is intended for.
Cost considerations include:
- The size of the property and the number of occupants
- Usage requirements and preferences
- Installation and heat loss of a property
- The energy tariff you are on
We will design a system specifically for your home, your family, and your specific usage requirements. What’s more, we offer a free consultation and quote right from the start with complete transparency about what’s involved in your heat pump journey.
Average air source heat pump installation costs based on home size
The costs below are inclusive of the £7,500 grant available, either through the Boiler Upgrade Scheme for England and Wales, or the Home Energy Grant for Scotland.
2 Bed Bungalow
Average Price = £5,300
3 Bed Semi
Average Price = £6,100
4 Bed Detached
Average Price = £7,200
Spread the cost into manageable monthly repayments
Relax. Don’t worry about funding the upfront cost to get a better heating solution for your home. With financing options available, it’s never been easier to switch over to an air-source heat pump.
Discover an illustrative finance example on an average heat pump install for a 3-bed semi-detached house, costing £5,500 (£13,000 before the government BUS grant). Credit is subject to status and affordability.
| 2 Year plan | |
|---|---|
| Cash price | £13,000 |
| Government grant (BUS) | – £7,500 |
| Balance | £5,500 |
| Deposit (15%) | £825 |
| Credit amount | £4,675 |
| Interest | n/a |
| Total amount payable (inc deposit) | £5,500.00 |
| Number of repayments | 24 |
| APR | 0% |
| Monthly payment amount | £194.79 |
Will a heat pump save me money on my energy bills?
According to research done by the Energy Saving Trust, an Air Source Heat Pump can save you £65 per year when compared to an A-rated gas boiler. Better yet, you can save around £240 per year when compared to an old G-rated boiler. While the running costs don’t appear to be too dissimilar, there are a lot of things to factor in.
One of the most important considerations is your energy tariff.
If you stick to your current energy tariff and pay the same kWh unit price for your heat pump, then the savings of switching from a gas-based system aren’t huge. However, you can choose a tariff specifically created for homes with heat pumps and significantly reduce the price you pay per kWh of electricity.
Better yet, the 300-400% average efficiency of a heat pump system over the year helps see a return on your investment much quicker than for a gas boiler – so you can enjoy many years of energy and cost-saving warmth for your home!
Want to know more? We go into more detail about working out operational costs here.
CB Heating: Expertise and
support you can rely on
Updating your home’s heating system is a big investment – so it’s always worth getting it right the first time by working with experienced heating engineers you can trust.
We’ve been installing air source heat pumps for over 20 years, we’re backed by energy giant EDF, and we pride ourselves on taking on complex, demanding system installations that other companies pass on.
We also make the process easy from start to finish, taking care of all the paperwork, including grant applications, and ensuring your installation is MCS certified.
For added peace of mind, your heat pump will be installed by a fully trusted and qualified installer in your area through the Heat Pump Installer Network.
Frequently asked questions
How much do air source heat pumps cost to install and operate?
Taking into account the £7,500 Boiler Upgrade Scheme (BUS grant), a complete heat pump system, matched perfectly to your requirements as part of our bespoke system design service and fully installed, can cost as little as £5,500-£7,000 for the average 3-bed family home.
Many customers find this a reasonable level of investment for a dependable, robust, and eco-friendly heating system.
You can find the BUS scheme eligibility criteria here, but we handle all the paperwork and applications, so it won’t be something you’ll have to worry about!
How efficient are air source heat pumps?
Air source heat pumps are one of the most efficient heating systems for your home. Generating three times the amount of heat for every kw of energy used. Heat pumps are sustainable, low carbon and help you save energy.
Do you need new radiators for air source heat pumps?
Not always, no but the performance of your heat pump system hinges on the compatibility and efficiency of your radiators.
Larger radiators with convectors are generally the best choice as they have a larger surface area. Careful evaluation and measurement of your existing radiators will ensure that your heating system operates at its best, providing comfort and energy efficiency.
How loud is an air source heat pump?
If you’re concerned about how loud an air source heat pump is, you might be surprised to instead find out how quiet they are. Like any machine in operation, heat pumps do produce noise – but how much noise they produce is remarkably low, especially with newer ASHP models designed with a focus on low-noise operation.
The noise is so low that it’s about the same as a whisper, the gentle hush of a library, or the sound of a breeze through leaves.
But if you’re curious to learn how a heat pump produces noise and how much noise it produces, read on.