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In the smart home: heat pumps

With talk of junking new gas boilers in the UK by 2025, heat pumps are very much the low-carbon alternative for people of the moment! Jonathan Atkinson from Carbon Co-op explains more...

At Carbon Co-op, we’ve seen enquiries go through the roof in the last few months, but it’s worth getting to grips with the technology before diving in.

Heat pumps act as a fridge in reverse. Heat is extracted from either water, trenches dug in the ground (Ground Source Heat Pumps, pictured below) or directly from the air (Air Source Heat Pumps) and used to warm water for radiators to heat a home.

Unlike gas boilers, heat pumps generate constant moderate heat, meaning radiators need to be replaced with oversized versions (or underfloor heating installed). Due to the lower heating potential, they work far better in well-insulated homes. An appropriate solution also needs to be found for hot water, for example, a tank with an immersion heater.

Heat pumps cost a significant amount to purchase, between £5,000 and £14,000 and generally require more to run than equivalent gas boilers because, although they use less energy overall, electricity is far more expensive than gas.

Fortunately, there are incentive schemes like the Renewable Heat Incentive (RHI), and if you are on a low income there may be local authority schemes available which replaced the very short-lived Green Homes Grant. It's important to spend time working out the overall costs. The quality of heat pump installations has also sometimes come in for criticism.

Oversized systems generally run less efficiently and can end up costing customers more in the long run. A crucial factor (identified by Tipperary Energy Agency from installations in Ireland) is the requirement to take accurate heat loss measurements of the home in order to appropriately size systems and radiators. With this in mind, it may be worthwhile getting an assessor or engineer to do some design work up front, rather than getting the whole job done by an installer.

Finally, look out for MCS (Microgeneration Certification Scheme) accredited installers – you need this accreditation to qualify for RHI and you can always go back to MCS to resolve issues.

All in all, heat pumps are an integral part of the energy transition in the UK, an exciting and transformative technology, but householders need to be well informed to deal with the complexities and potential pitfalls.

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