What will it cost to achieve EPC C-ratings across the entire housing stock in my area?

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Achieving full EPC C coverage in your area

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The acute need for action and investment to meet carbon reduction targets is now understood by more people than ever before. We simply must act – and quickly.

But do we even understand what that implies…and what it will cost?

The Climate Change Committee estimates that £50bn investment is needed in the UK annually to meet 2050 zero carbon targets. The source of carbon emissions targeted by that investment will range across transport, agriculture, and buildings – both commercial and domestic.

Domestic retrofit involves implementing a range of energy performance measures in our homes – such as improved insulation, glazing, or simply energy efficient lighting. And the impact could be huge – domestic buildings currently make up nearly 20% of the UK’s carbon emissions.

This is where C-Path comes in - an accessible, cloud-based platform that has been designed to allow the user to design a domestic retrofit programme in a matter of minutes. The automated C-Path evidence base can analyse retrofit opportunities down to an individual property level…but as we collectively wrestle with grasping the scale of the task we are finding it is often the much higher-level questions that our clients are seeking to understand. For example ‘what would be the total cost of implementing domestic retrofit measures across my local authority area?’

Having recently worked with a large proportion of local authorities in the South East Local Enterprise Partnership (SELEP) region, we can readily - and instantly! - illustrate some of the answers to these questions using C-Path.

The scale of the opportunity is huge.

At a SELEP level – hat investment ranges from an estimated £1.6bn in the largest SELEP local authority (ranked by number of homes) to £560m in the smallest.

At every local authority level

What about the aspiration for EPC C-ratings?

The Energy Performance Certificate (EPC) register is the government's online database of every EPC in the UK. The Government's current aim is to have as many homes as possible reach a C rating by 2035 in England and Wales. If we use C-Path to calculate the cost of (where possible) achieving a minimum of EPC-C across all homes at a SELEP level, the numbers remain significant.

The investment opportunity - or need, depending on your perspective - is estimated at up to £10.7bn across SELEP, ranging from £521m in the largest local authority to £259m in the smallest.

The average cost of 'getting to EPC-C' is extremely variable

Across SELEP, the average cost per home of implementing all measures to achieve a C-rating is estimated at between c.£3k and c.£20k, on average per home, depending on the local authority.

The variability reflects the nature of the housing stock in different areas. Some have higher proportion of rural / off gas areas, others have a higher incidence of hard-to-treat solid walled properties.

This illustrates the significant importance of understanding the data and knowing the characteristics of your own geographical area.

If you work for a local authority, and you're interested in knowing more about the opportunity in your area, please get in touch because we would be delighted to discuss the data with you.

Measure for measure

C-Path applies a logic based approach to prioritisation of measures to achieve a C-rating for all those D, E, F and G rated dwellings that need attention, on a targeted, property-by property basis. Focusing first on efficiency improvements, we then apply the most cost effective heating and energy generation solutions to ensure the investment needed to achieve a C-rating is properly optimised.

But where are the opportunities most pronounced for investors and contractors? Based on getting to EPC-C, the top 5 measures in the south east region by total cost aren't necessarily a surprise, and include: photovoltaics, solid wall insulation, solar thermal systems, heat pumps and other forms of wall insulation, including party wall.

This is about so much more than the costs

Based even on this research, there are huge opportunities for businesses to invest in and deliver domestic retrofit measures across the SELEP region – and is equally the case across the UK. Focussing on the costs is only one part of the story though – the energy savings, carbon reduction impacts and employment potential associated with this level of investment would be transformative. More on these opportunities wil follow in later articles.

Want to know more?

If you are a local authority, investor, or housing association anywhere in England and Wales and are keen to understand the domestic retrofit implications and opportunities associated with your housing stock, C-Path can help – just contact us on, or follow the link below to our contact form.