Retrofit | Heat pumps

What is a Heat Pump?

Heat pumps are part of a wider transition towards electrification of much of our end-use of energy (see The Future Is Electric).

A Heat Pump is based on the principle of heat transfer. Heat transfer uses a small amount of energy to transfer the free and renewable low-grade heat from the air or ground to high-grade heat suitable for space or water heating in homes.

Heat pumps are extremely efficient and are a proven technology. For every unit of electricity to run a heat pump, they deliver at least three units of heat (i.e. at least 300% efficient).

And when replacing an old gas boiler, running costs do not need to rise when installing an air-source heat pump, as we explored in How to heat your home with the minimum amount of energy, and save the planet. Installing a heat pump is the single biggest thing a householder can do to reduce the carbon footprint of heating.

For more insight, please go to our piece on Demystifying Heat Pumps.

Eight common myths about heat pumps

Top 10 tips for heat pumps

Replacing your old fossil fuel boiler with a heat pump will reduce your carbon footprint more than anything else you do.
Because heat pumps are so efficient, bills can be cut by 40% against oil/LPG, 25% against mains gas, and 75% against direct electric (‘resistance’) heating.
Seek advice from specialised heat pump firms (MCS* registered).
Get the supplier to explain what they do, and any steps you need to take.
Ask for a reference client with a similar property to share their experience.
Take cost effective insulation and draughts improvement measures.
Design is key. Ensure heat load/ emitter (e.g. radiator) assessments are performed,
Understand the differences between heat pumps vs traditional boilers.
Air Source Heat Pumps are almost as efficient as Ground Source Heat pumps.
Let the heat pump do its thing!
*MCS - Microgeneration Certification Scheme

Boiler Upgrade Scheme

The Renewable Heat Incentive (RHI) is no longer available. It has been replaced by a less generous but up front grant of £5,000 for Air-Source Heat Pump (ASHP) and £6.000 for Ground-Source Heat Pump (GSHP), which largely removes the RHI’s bias in favour of GSHP. This means that financially and in other respects, most householders are expected to opt for an ASHP when opting for a heat pump.

There remains eligibility requirements related to the household Energy Performance Certificate (EPC), such as the need to insulate the loft, or do cavity wall insulation, if the EPC report recommends it. See https://www.gov.uk/guidance/check-if-you-may-be-eligible-for-the-boiler-upgrade-scheme-from-april-2022#eligibility

With the new scheme, all the paperwork is done by the designer-installer, and the grant money comes off the project price.

Air source heat pumps

An air-source heat pump in a retrofitted stone cottage

Above: George Clarke with an Mitsubihi Ecodan R32

Above: 300l cylinder plus header for underfloor heating coils

Water source heat pumps

Water source heat pump in Nailsworth

A Great Introductory Talk on Heat Pumps for householders

To learn more about heat pumps, and dispelling common myths about them, please see the engaging talk by Chris Wilde (Managing Director of Yorkshire Energy Systems), that we hosted What if we could all heat our buildings with renewable technologies?

Calling heating engineers!

Are you a heating engineer who is experienced in gas boilers and curious about learning more about heat pumps? For you and others curious about learning more about the nuts and bolts of installing heat pumps, from an engineers perspective, take a look at these training resources.

And just announced:

“The Secretary of State for Business, Energy and Industrial Strategy, the Rt Hon Kwasi Kwarteng MP, has welcomed the launch of a new training course that will overhaul the route to becoming a heat pump installer in the UK.”

Explore another retrofit measure:

Windows and doors