Last year, the UK Government set a clear ambition to decarbonise heating across all housing and building stock to achieve net zero carbon by 2050. For those on the gas grid, electrification and hydrogen are viable options – but for the 1.1 million homes in England1 off the gas grid, there are a number of different challenges to address.  

Mark Wilkins, Technologies and Training Director at Vaillant UK discusses the government’s recent consultation on phasing out fossil fuels for homes off the gas grid, and the key considerations for zero fossil fuel installations.

The journey to net zero

The Scottish Government published its Heating in Buildings Strategy in early October 2021, which was followed swiftly by the UK Government’s Heat and Buildings Strategy. Whilst there are some key differences in both, the direction is clear. For the UK to reach net zero carbon by 2050 (2045 in Scotland), we must decarbonise heat across the majority of building stock.

The heating of 30 million UK homes and buildings currently contributes to 23 per cent of all UK carbon emissions2. Currently there is a government ambition to phase out the installation of new natural gas boilers in on-gas areas from 2035. For those off the main gas grid, an earlier phase out date of 2026 in domestic and small and medium buildings has been proposed; with a target of 2024 in large non-domestic properties. 

There are currently 1.1 million homes in England off the gas grid that have fossil-fuel heating systems, 78 per cent of which use oil as their main source of fuel – which is also the most carbon intensive. 13 per cent of homes use liquid petroleum gas (LPG) and 9 per cent use coal1

For on-grid homes, hydrogen is a potentially viable option in the future. However, as this will involve utilising the existing gas network infrastructure, it won’t be available to off-grid buildings. It’s for this reason that decarbonising heating systems off-grid through electrification – e.g., the installation of heat pumps – has been labelled a ‘low regret’ option by the government.

Supporting the industry

There are two clear strategies for decarbonising heating systems in off-grid buildings, including bringing an end to new fossil fuel heating installations from 2026 and the adoption of a ‘heat pump first’ approach to replacing heating systems. A consultation on the proposals, which Vaillant participated in, concluded earlier this year. 

From a heating industry perspective, it’s important to consider whether a 2026 end date for the installation of fossil fuel heating in homes off the gas grid will give both specifiers, installers and homeowners sufficient time to prepare. 

As part of the consultation, Vaillant highlighted that the immediate challenge for facilitating a 2026 end date and taking a ‘heat pump first’ approach, will be in ensuring there is an adequate number of skilled heating engineers. 

These skills are urgently needed in the new build sector, and particularly if off-grid homes are obligated to accelerate decarbonisation of their heating systems more quickly.

In terms of future-proofing the industry in the years to come, developers and housing providers will need heating engineers who can install the most suitable low-carbon system for a property – not just specialising in a singular technology, such as heat pumps. This is a significant step change for our industry, and to achieve the targets the government has outlined, it must be fully supported. Getting the required skills and training should be straight-forward and cost-effective, particularly for SME’s who will require financial support to facilitate this transition. 

There are additional challenges for those in the social housing or buy-to-rent sector, who will also have a maintenance responsibility after a property has been built. Manufacturers need to work proactively with providers and associated agencies such as in-house maintenance teams and contractors, to ensure there is a shared understanding and knowledge of low-carbon technologies across the supply chain. 

Heat pump first approach

With the limited options for off-grid homes, a ‘heat pump first’ approach could be beneficial. In fact, modelling by the Department of Business, Energy and Industrial Strategy (BEIS) found that 80 per cent of properties would be suitable for a heat pump – based on current energy efficiency and electrical limits.1

If a property is off the gas grid, it’s likely that the heating system currently being used will be an oil or LPG boiler, and in these cases, there are immediate carbon savings to be made by changing to a heat pump.

Heat pumps have existed for many years and are a tried and trusted solution across Europe that can help decarbonise homes today. With government funding being made available for UK homeowners to adopt this technology, heat pumps are growing in popularity. 

Generating public awareness on the topic of low carbon heating solutions in relation to climate change, supported by financial incentives, will be key to wide-scale behavioural change. It’s essential that the industry comes together to share expertise, ensuring that those off the gas grid, including social housing tenants and homeowners, are familiar with low carbon heating technologies and how to get the most out of them.  

For specifiers, educating developers and social housing clients on the latest regulations and having a broad knowledge and understanding of low carbon technologies, now and in the future, will help futureproof these types of projects and installations.

System first approach

As the off-grid market stands today it is clear that there is no ‘silver bullet’ and that a multi-technology approach is required to help the UK reach net zero. 

In principle, heat pumps are the immediate option for decarbonisation today, but this approach must be assessed on a case-by-case basis and consider the fabric upgrades required in a property, as in some cases these costs may be prohibitive.

For those living in off-gas areas and currently using oil, upgrading to an LPG boiler is a good way to start the low-carbon journey and futureproof heating systems in the short-term. BioLPG, which is produced from renewable sources such as vegetable oil, can then be used as a drop-in fuel in existing LPG heating systems. 

Although biofuels are already available in the UK, it is still regarded as a novel fuel and therefore global production levels are low. The UK government are currently assessing the role biofuels will play in the overall net zero journey through its Biomass Strategy, including availability and sustainability of supply. If successful, it could be that a hybrid system combining a bioLPG boiler and an air source heat pump will help biofuels to go further and offer a solution for homes where a standalone heat pump is not feasible.

Further support needed

To ensure buy in from future homeowners and tenants, the running costs of a heat pump (or other low-carbon technology) must be favourable compared to their current heating appliance. The focus from government should therefore be on generating market pull to accelerate low carbon technologies with proposals that are beneficial to consumers. 

This has started to be addressed, and the government has committed to addressing the disparity between gas and electricity prices for on-grid properties. In addition, Vaillant has also called for a pricing appraisal on raw fuel costs in off-gas circumstances, as without an instant fuel price reduction, consumers are not going to see an adequate benefit in changing their heating system.  

Without this, the transition to low carbon heating will be more difficult and high efficiency boilers within the retrofit market will continue to be the preferred heating source for the immediate term – until an outright ban of fossil fuels is triggered. If we want off-grid consumers to adopt low-carbon technology sooner, technologies like heat pumps must be able to grow in accessibility and popularity.