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 are of the most efficient ways of heating your home sustainably with minimal maintenance.

You may be wondering what they are, how they work, and a few other questions like cost. To make it super easy, we’ve covered it all in this ultimate guide.

What heat pumps
& how do they work?

Heat pumps, including air source varieties, transfer energy rather than creating it.

You may already know that energy is never created or lost, but simply moved. When heating your home using something like a wood burner, fireplace, or a gas/oil boiler, you’re relying on the energy stored in those materials for the heat.

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 down 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. 

But, 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 – they’re not a source of energy in themselves but simply move energy from one place to another.

But heating your home is clearly not as simple as pulling in air from outside in the depths of winter – you’d then just have a cold house! The question, then, is where do heat pumps move energy from?

Logic Air Heat Pump Installed Outside Property

The simplest description of how heat pumps work is this:

  1. Refrigerant Circulation: A refrigerant circulates through an evaporator.
  2. Air Intake: A fan draws outside air over the evaporator, where it absorbs energy.
  3. Vaporization: The absorbed energy causes the refrigerant to vaporize.
  4. Compression: The vaporized refrigerant is compressed, generating heat.
  5. Heat Exchange: The hot vapor passes through a condenser, transferring heat to your home’s water-based heating system.
  6. Cooling and Expansion: The refrigerant, still under pressure, is cooled and then expanded, restarting the cycle.

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:

Safe 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.

Different types of heat pumps

There are three main mediums to 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 soruce heat pumps are the most effective option. 

Ground soruce 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 and in-filled. These pipes draw heat from the soil in which their buried in. 

Water soruce 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). But 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.

Water soruce 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 actually the most reliable, and cost-effective solutions (in certain climates).

Rather than running a long loop of glycol (water-antifreeze) through the ground, 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 then pulls air over that 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 installing an air source heat pump 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!

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).

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.

Current heating system

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.

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.

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 but, essentially, heat pumps aren’t loud for two reasons:

  1. Modern designs have dramatically minimised noise
  2. You’re rarely standing next to the unit

The heat pump units we choose for 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.

So they’re already 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 & 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.

In fact, the Ideal units we supply hold the UK Quiet Mark certification for being among the quietest available.

How much does an air source heat pump cost?

Like 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, unfortunately, to give a specific set of numbers because there’s so much variability between installations and requirements.

That said, some of the usual considerations for cost are:

  • The size of the property and number of occupants
  • Usage requirements & preferences
  • Installation & heat loss of a property
  • The energy tariff you are on

All of our considerations for an installation are completely bespoke to you, your property, and your usage requirements – and we offer a free consultation & quote right at the beginning.

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 £340 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 & 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 make the process easy from start to finish. Taking care of all the paperwork, including grant application 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.