Air source heat pumps vs ground source heat pumps
If you’re thinking about having a heat pump installed in your home, you’re most likely considering an air source heat pump or a ground source heat pump.
Both absorb heat from the environment and transfer it to heat our homes. But how does each heat pump differ? Is one better than the other?
How they work
The main difference in how an air source heat pump and a ground source heat pump works is where each unit draws its heat from. The clue of course is in the name, with one using air and the other using the ground.
An air source heat pump draws heat from the air, so the unit is placed outdoors so it can absorb heat through a fan in the pump. A ground source heat pump draws heat from the ground by running refrigerant through buried pipes.
Both air and ground source heat pumps are eligible for the Boiler Upgrade Scheme, a government grant of up to £7,500 for homeowners living in England and Wales. Although, the upfront cost of ground source heat pumps is significantly more than air source heat pumps – around £29,000 vs £12,000.
When to choose an air source heat pump
Air source heat pumps are generally suited to all homes, even flats and apartments, as long as you have a well-ventilated outdoor space. Most ASHPs require two metres of free space in front of them to help avoid any cold air short circuiting back to the unit.
There aren’t many other requirements for an ASHP – no planning permission is needed and you’re not required to dig up any part of your garden.
The process of installation is simple, less expensive and less disruptive than that of ground source heat pumps.
Most air source heat pumps can vary their output to suit the energy requirements of the home. The amount of carbon emissions you will end up saving depends on the heating system you are replacing it with.
When to choose a ground source heat pump
Ground source heat pumps require homeowners to have extra outdoor space. Pipework is installed horizontally about a metre under the ground’s surface or vertically, and deeper, which can be an expensive job.
In most installations the heat pump unit itself is installed in your house, but you’ll need an area around the size of two fridges for the pump and the internal pipework and controls.
Despite their extra costs, ground source heat pumps do tend to be quieter than air source heat pumps and are less sensitive to weather. An air source heat pump produces plenty of heat, even in freezing temperatures, but they have to work harder to do it. As the temperature underground varies very little throughout the year, ground source heat pumps are largely unaffected by the weather and the seasons.
How efficient are heat pumps?
Both have a typical efficiency rating of 300%, which is three times better than the average gas boiler.
A modern gas boiler can be up to 90% efficient, and a conventional electric heater is 100% efficient. However, because a heat pump is primarily moving heat rather than generating it, it can be around 300-400%. In other words, for every kilowatt hour of electricity it uses, it could bring 3.5kWh of heat into the home.
Whether you pick an air source or ground source heat pump, you’re likely to save on the cost of using an oil boiler. Both heat pumps use around the same amount of electricity to warm your home up, so your energy bill will roughly be the same either way.
Choosing the right heat pump for your home will depend on several factors including how much space you have available outside and how much money you are willing to spend upfront. Both will help you cut energy costs and heat your home efficiently, as well as improve your carbon footprint.
For most homeowners, we believe air source heat pumps have the edge because of their cost effectiveness and the quickness of the installation process.
We’re MCS-approved installers of Vaillant UK air source heat pumps and will not only advise you on your eligibility for the Boiler Upgrade Scheme (BUS) but will apply for it on your behalf. The full claim is deducted from the cost, so you don’t have to wait for payment.
Try our quote tool for a free instant air source heat pump quote, or contact our experts to discuss a complete green energy solution for your home – sales@eerenewables.co.uk or call 0800 802 1116.
