Net zero pathway – direct acting solutions for existing homes

Introduction

The consultation revising Part L for existing homes raised challenging conversations across industry on how we will tackle the existing housing stock to reach net zero in 2050. One of the more complex of these is addressing the decarbonisation of heat and the role of direct electric solutions.

As the UK moves towards the electrification of heat and the net zero target, the UK Government will need to introduce specific measures to help transition the existing housing stock towards more sustainable solutions. This is will be no mean feat, with the cost and complexity of addressing privately owned homes a vital yet difficult landscape for the Government to navigate.

The key to doing so correctly, alongside well-managed financial incentives, is to bring the public on this journey rather than enforce it upon them, an element of which must be to offer choice and flexibility. With this in mind, what can direct electric solutions offer to the decarbonisation of heat, and why should the Government support them alongside heat pumps as a natural-gas alternative?

There is no silver bullet...

There is no silver bullet to reaching the 2050 target. In some existing dwellings, direct acting solutions will be the best - and possibly the only - net zero compliant retrofit for that project.

When heat pumps can’t be used

Although heat pumps are certainly a key technology in our future, not all existing dwellings easily lend themselves to them in the short to medium term, as noted in BEIS Heat Distribution Systems report.

Where they are not feasible, homeowners should not have to stay with a higher carbon solution when suitable alternatives are available. Heat pumps may not be suitable due to lack of space, budget constraints or occupant requirements and preferences. This is where hybrid systems containing a heat pump element can be introduced as a complementary interim measure to the full uptake of heat pumps.

An example would be pairing a hot water heat pump with direct acting panel heaters or high heat retention storage heaters. In this specification instance the capital cost of heating and hot water upgrades would be lower, leaving budget for additional measures such as fabric improvements and controls. This would further reduce the primary energy usage and carbon impact of the new system when compared to that which is being replaced. The regulations should therefore not discourage this type of improvement.

As gas becomes more expensive

The Government is looking to address the levy imbalance across gas and electric, as suggested in the Cost of Energy Review. When this change takes place, homeowners will be looking to transition away from gas-based systems. There should be as many alternatives as possible to allow them to do this, for a range of capital and operational budgets. This would help to avoid the exclusion of low-income households and the fuel poor.

Direct acting solutions offer design flexibility and a low-cost solution to futureproofing small, well-insulated houses and flats. Should direct electric not be an option, there could be a rise of those living in fuel poverty who are unable to afford to retrofit a heat pump solution. No appropriate technologies should be ruled out for these homes to transition to, or homeowners could be trapped into staying with a higher cost energy source.

To align with proposed spending caps

For landlords, consultations around spending caps on refurbishments could create contradicting scenarios, such as those included in the call for evidence ‘Improving the Energy Performance of Privately Rented Homes in England and Wales’. The cost and complexity of traditional heat pump application could mean that landlords surpass the threshold for required spend which may put them off making any improvements.

It is better in these circumstances to have a range of electrification options that enable the application of a hybrid electric heat pump solution. As in the previous example, a lower capital cost hybrid solution would leave funding for fabric improvements, which combined with the ongoing reduction of carbon and primary energy associated with electricity, would produce a significantly better performing building compared.

For system diversity and demand side response

One of the key concerns around the specification of direct electric solutions is grid capacity. However, retrofitting the existing housing stock to enable flexible energy storage, through technologies such as the Quantum High Heat Retention Storage Heater, would mean that renewable production could be prioritised over fossil fuels and wind curtailment could be reduced or removed.

To complement smart tariffs and meters

As the UK continues to roll-out smart meters across the existing housing stock, there has been an emergence of smart electricity tariffs by companies such as OVO Energy. Smart connected direct electric heaters, high heat retention storage heaters and sanitary hot water heat pumps, all linked to such tariffs, could make a substantial contribution to grid decarbonisation and the electrification of low carbon heat. What’s more is that these systems would grow and contribute alongside other industry electrification plans, such as the roll-out of smart electric vehicle charging models.

This should be a supported pathway to net zero, encouraging smarter tariffs and greater diversification of specification to reach our 2050 goal, rather than discounting viable technologies which we may some day soon come to rely on.

Remaining flexible in addressing the challenge

Getting the existing housing stock to net zero is going to require specification flexibility. Industry needs to use the best solution for each project and not be forced to shoe-horn options which do not fit all requirements or budgets.

Related articles on Designing Buildings

• Heat pump.
• Performance gap in low energy housing.
• Smart meters.
• Zero carbon homes.