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Heat Pumps & Direct Electric Heating – a partnership to net zero

Heat Pumps & Direct Electric Heating – a partnership to net zero

If you search for information on heat pumps via Google or any other search engine, you will see a mass of opinion. Some articles claim heat pumps to be the only heat source solution for helping to reach net zero whilst others take a more conservative approach. So, for the ‘neutral’, trying to get any sense of clarity on what is best for heating our homes in the future is a bit of a minefield.

As a manufacturer of electric heating, we wanted to unravel some of the opinions to answer the question; will heat pumps replace direct electric heating?

What we discovered, in short, is that the answer is ‘no’. But we wanted to explore this further.

The role of heat pumps

What are heat pumps and how do they work?

Heat pumps are one of the most efficient systems to use for heating and cooling. They move heat by using a compressor to circulate either a gas or liquid refrigerant. For example, an air source heat pump absorbs heat from the air outside into the refrigerant. The refrigerant gets compressed by the pump to increase its temperature and then it is condensed to release the stored heat into your home.

Ground source heat pumps work slightly differently. Instead of absorbing heat from the air (yes, you guessed it), they absorb heat from the ground via a mixture of water and antifreeze which is pumped around a network of pipes buried underground.

Heat pumps and the journey to net zero

Heat pumps are being heavily back by government yet comparative studies between heat pumps and direct electric heating have not been carried out in real world situations.

In addition, a recent article published by the Express suggested that for many homeowners, ripping out gas boilers and replacing them with heat pumps could cost in excess of £20,000. This is because installing a heat pump is only part of it. Many millions of poorly insulated homes will need money spent on significantly improving the insulation of their home to make the heating system energy efficient. A project like this can cost around £10,000 on its own.

Dr Matthew Aylott – Senior Policy Adviser, Department of Business, Energy and Industrial Strategy (BEIS) suggests that “Government is only recommending the installation of heat pumps in ‘fit-for-purpose’ houses.” These would be predominantly well insulated new build homes.

There’s no disputing it, heat pumps will play a large role in meeting net zero but some of the hidden challenges around them seem to not be addressed. However, the addition of direct electric heating will enable even greater efficiencies both directly and through hybrid heat pump installations.

Points to consider about heat pumps

  • Studies are usually done in ‘ideal circumstances’ so there’s a difference to what happens in reality.
  • Even though heat pumps are said to be 300% efficient, with real world data, heat pumps combined with supplementary water heating (which is required to complete the system) require more energy than other direct electric heating systems making them less carbon-efficient and more expensive in the long run.
  • To be most effective, heat pumps have to use hydronic heating systems making them less practical for retrofit applications.
  • Heat pumps have a very high capital cost compared to other electric heating systems available in the UK.
  • With the government continuously promoting heat pumps, there is a misconception that it’s a generic solution to the problem of delivering low-carbon heating – it is only part of the story.
  • Much of the energy created is lost (up to 35%) in the transfer of hot water around the property but tests do not take this into account. Additional cost is added because extra-large radiators have to be used for the heat pump system.

There is certainly a future in heat pumps but that future is in buildings that have the ‘ideal circumstances’ in place. Ideal conditions include:

  • When there is ample outdoor space for the unit
  • When temperatures are above 12 degrees
  • When buildings are highly insulated so flow rates can be slower

Filling the gaps that heat pumps leave

For a significant number of buildings, heat pumps could be viewed as just a medium-term recommendation by the government while more thorough field tests are being completed on other, more effective heating systems.

In short, heat pumps will have their place, but they aren’t necessarily the one size fits all approach to efficient low-carbon heating. They are more suited to new-build projects, and not so well suited to retrofit. With over 26 million homes needing to be upgraded, it is questionable if heat pumps have the answer.

With this in mind, there are other ways of heating which fill the gap that heat pumps leave. This includes renovations, smaller houses, flats and generally buildings where wasted space is an issue.

Options for low-carbon direct heating:

  • Electric underfloor heating
  • Instantaneous electric water heating
  • Electric boilers
  • Electric radiators
  • Hydrogen

These options fit nicely with the rental housing market in particular. For heating in a rental property, the ideal situation is:

  • Easy installation
  • Zero maintenance
  • Efficient and controllable heating
  • Energy-saving features
  • Smart heating compatibility
  • Sustainable and eco-friendly

Direct electric heating fits into all of these categories and can be installed in to any property (often coming out with better efficiency ratings) even where space is at a premium.

Atamate, a smart building software company in Oxford, wrote a brilliant piece on air source heat pumps and direct electric heating in a typical setting in London. The results research shows the air source heat pumps compare unfavourably to direct electric heating derived from main electricity when using real world data.

Comparison of predicted direct electric heating

When is direct electric heating an option for UK homes?

  • When heat pumps can’t be used
  • To supplement heat pumps so that it can operate in its sweet spot rather than be strained to low efficiency of trying to operate in non-favourable conditions.
  • As gas becomes more expensive a very straightforward upgrade for a property one room at a time.
  • To align with proposed spending caps
  • For system diversity and demand site response.
  • To compliment smart tariffs and meters – direct electric heating is much more efficiently controllable zone by zone.

The main place that direct electric heating is going to fit into the market is primarily where space is at a premium. This includes renovations where you can’t change the full heating system to suit a heat pump. In this instance a swap for an electric boiler could be the answer. However, if you are renovating the floors then a low-profile underfloor heating would be ideal.

Direct electric heating is going to fill the gap where heat pumps have a low performance or where they can’t be installed practically. There’s space in the market for both, and in many cases they will work alongside each other but the market can’t do without one or the other.

Together they meet the market needs and that’s where the future lies.

If you have any questions regarding the future of direct electric heating or further information on the electric heating range, please reach out to one of the team on 0800 019 5899 or contact us another way.

Chris Hedges

Chris Hedges

Chris is the Senior Marketer at ThermoSphere and brings over 20 years’ experience in marketing, 8 of those within the built environment. He has an equal blend of creativity and analytical scrutiny with the belief that electric has a huge part to play in reducing carbon emissions.

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