Air or ground source heat pumps?

When you look at the heat pump market, air source systems have become more popular than their ground source cousin. But this hasn’t always been the case.

Around seven years ago, the ground source pump appeared to have won the renewable tussle. This was mainly down to the higher efficiency levels achieved over air source systems and the proven reliability of providing excellent space heating.

But this comes at a cost – literally. Ground source heat pumps are more expensive to install and there’s a lot more disruption, with the systems needing to be fitted into a borehole in the garden. For this reason, interest in air source pumps has increased as the installation process is much simpler and there is no need for ground works.

In the middle of winter you’ll probably see better efficiencies with a ground source pump though, mainly because temperatures in the ground stay at a pretty consistent heat. However, remember that air source heat pumps can still extract warmth from temperatures as low as -15 degrees Celsius. This temperature can then be increased with a compressor so it’s suitable for your home.

So how do the two systems compare when you look at the financial incentives?

First there’s the Renewable Heat Premium Payment (RHPP) grant which is available for both installations. The grants have recently been increased because of delays in the Renewable Heat Incentive.
The new grants are now:

  • Ground source heat pumps: £2,300
  • Air source heat pumps: £1,300

The RHPP scheme is intended to help homeowners with the initial installation costs and so far 10,000 people have taken advantage of the vouchers.

The Renewable Heat Incentive (RHI) is a separate scheme entirely and acts in a similar way to the feed-in tariff for solar panels. The scheme has been delayed by the Government until 2014, but once in place will pay out for every unit of renewable heat generated.

Indicative tariff ranges for heat pumps are as follows:

  • For air source heat pumps (6.9-11.5p/kWh)
  • For ground source heat pumps (12.5-17.3p/kWh)

The RHI is one of the key ways homeowners will recoup installation costs and see a profit with their renewable product. Of course, the energy savings also factor highly.

So which heat pump is best for my home?
Ground source heat pumps will probably provide your home with the best long-term benefits but justifying the extra installation costs and initial disruption can be hard. Air source heat pumps are far easier to fit and are attached to an external wall of your property.

Essentially it comes down to whether it’s efficiency you’re after or a cheaper and easier installation. Ground source heat pumps can work up to 20% better than their air source equivalents and will probably have a longer life expectancy. The higher RHI tariff could push you towards geothermal systems too.


Facts & Figures You’ll Love To Share

  • A heat pump is capable of generating enough heat to reduce your annual energy bills by up to £650.
  • The Government’s Renewable Heat Incentive will pay out hundreds of pounds a year for the renewable heat produced.
  • Cash grants of up to £2,000 are available to help fund the purchase of heat pumps.
  • As gas and electricity prices continue to rise, heat pumps will provide greater savings for the years to come.

Tom Crosswell

I have been managing online projects since 1999 and I'm a experienced marketeer, who is well versed in international brand management, online business strategy and developing long term relationships. Through my academic and professional background I am a specialist in generating online loyalty towards brands. My experience has taught me that ultimately business is about relationships and people. For more information see my Google+ page.

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