The UK will need to switch from fossil fuel to low-carbon heating in around 28 million homes to tackle climate change. Heat pumps and heat networks are likely to be by far the most common low-carbon heating option. But can heat pumps work in most homes in the UK? And what role are different types of low-carbon heating – air source, ground source, and heat networks – likely to play? This project update sheds light on which homes and neighbourhoods are most suitable for different types of low-carbon heating.

We want to create a robust, reliable and freely accessible dataset, enabling people to challenge and verify assumptions about heat pump suitability. Our dataset will cover Great Britain at a neighbourhood scale and will provide insight and local context for low-carbon heating. We will use this information to illustrate the strategic choices required to decarbonise home heating, such as balancing air-source heat pumps alongside other low-carbon heating systems, and approaches to clean heating in city centres.

Ultimately, we want this to be a resource used by other organisations to identify local areas for specific home decarbonisation technologies and interventions, like coordinated switching.

In our first phase of the project, we developed a first prototype of the dataset which can be downloaded here and map to share for small areas in England and Wales. The second phase will focus on refining our preliminary results and including Scottish data.

Our results are given for small, local geographies called lower layer super output areas (LSOAs) which comprise between 400 and 1,200 households. Here, we refer to these areas as ‘neighbourhoods’.

Unbiasing the EPC dataset

Routinely collected Energy Performance Certificate (EPC) data is a rich source of information about Britain’s homes – and is at the core of this project. However, the EPC dataset covers only two-thirds of properties in England and Wales and is not representative of UK property characteristics. Using Iterative Proportional Fitting and 2021 Census data we reduced bias in the EPC data, helping us to generate more accurate insights.

Defining heat pump suitability features

One of the challenges in assessing heat pump suitability is to set criteria for what makes a home suitable for a particular technology. We have used two sets of criteria in this project: one a ‘conventional’ view, which we think reflects common consensus, and one a Nesta view, which draws on our latest research. We did this for four different technologies: air-source heat pumps (ASHPs), ground-source heat pumps (GSHPs), heat networks (HNs) and shared ground loops (SGLs).

Key factors identified for determining the suitability of a home for heat pump installation included:

• EPC rating*
• garden size*
• whether the property is listed or in a conservation area
• property density
• urban/rural status
• connection to the gas grid.

* For these two factors, Nesta’s view is less restrictive than the ‘conventional’ view in determining suitability. We believe heat pumps can run efficiently in less well insulated homes and that noise concerns can be managed effectively without the overly restrictive one metre rule.

Mapping heat pump suitability

Using a rule-based scoring system created with the criteria above, we calculated prototype suitability scores for each heating technology in each of the local neighbourhoods of England and Wales.

Our interactive map shows the results of these scores. Below, we highlight three things that stood out to us to demonstrate the type of insight they can provide.

1. Cities are most suitable for shared technologies

Maps showing neighbourhood suitability for air source heat pumps and shared ground loops across England and Wales

Most of the country is highly suitable for ASHPs apart from major cities, where suitability is lower. When conditions like tightly packed housing make individual ASHPs unsuitable, our initial results show that shared technologies (SGLs and HNs) are suitable. Shared technologies are therefore likely to play a critical role in decarbonising homes in densely populated areas.

2. Air-source heat pumps are suitable for a large majority of homes

We believe that the conventional view, that homes need to be highly insulated with large gardens, underestimates the suitability of homes for ASHPs and GSHPs. This is demonstrated in our map, where the overall pattern of suitability is the same, but the suitability scores are higher under Nesta’s view – with many areas being at least 80% suitable for an ASHP.

3. Some areas present a nuanced picture of which technology is most suitable

In some areas we see a more nuanced story of suitability, like in South Wales. Outside of cities, other parts of the region, including the Valleys, show a broadly similar level of suitability for ASHPs, and quite varied suitability for SGLs. This demonstrates that many areas have genuine choices to make between different technologies. We did not determine the best heating technologies in our analysis, but neighbourhoods and local households may need to decide what system works best for their area.

Our first phase of the project has enabled us to reduce bias and enhance the EPC data with additional features, and show our preliminary insights on heat pump suitability across England and Wales. The computational approaches behind this are all available on our Github repository.

We found that shared technologies tend to be suitable in cities, with ASHPs and GSHPs suitable in most other areas. However, there are enough exceptions to this rule to warrant a more granular approach to assessment.

Over the second phase of this project, we want to refine all our steps - making them more robust, reliable and useful. This will include:

1. adding Scottish regions to our dataset
2. including more features, like electricity grid capacity
3. improving the usability of our interactive map.

Nesta has argued for a more coordinated approach to low-carbon heating, which includes local planning and zoning of heat technologies, and more support for shared neighbourhood heating schemes. We believe tools and good data are critical to making strategic decisions about low-carbon heating.

If you have any thoughts or suggestions about any of the above please fill in our feedback form.