EPCs: how to capitalise on open source home energy data

More data on the UK’s homes has been made freely available than ever before, after the Department for Communities and Local Government (DCLG) released all its energy performance certificate data via its new Open Data system.

Previously, records could be purchased at £0.11 per home. But now, householders, businesses and researchers can freely access the Energy Performance Certificate (EPC) register, simply by signing up to the site and agreeing to data protection conditions.

We spoke with Energy Saving Trust’s local delivery manager, Karen Strandoo, to find out more about what it might mean for those looking to use the data—and more broadly, energy efficiency in the UK.

Making sense of the data – four challenges ahead

It’s expected that local authorities and housing associations will be the main parties which will look to benefit from the release. But there are specific challenges presented by the data that could prove difficult to navigate for the inexperienced.

Karen said: “From working with housing stock data over the course of many years, we’ve identified four key challenges. Firstly, there is outdated and duplicated EPC information on the register, and that’s not straightforward to identify. It might look like duplicates, but you might actually be looking at different flats within a building.

“Then, there is incomplete EPC coverage. Only homes that have been built, bought, sold or retrofitted since 2008 have an EPC, which represents about 50 to 60 per cent of homes within a local authority area. So a significant number of homes will have no data at all.”

Mind the gaps

The release of the data is part of a broader move by DCLG, abiding with the local government transparency code that was established in 2015. Such data is already available in Scotland, so it’s also a matter of simply coming into line.

But while greater access to data is laudable, how it’s presented is often key to understanding it. Here, then, is where you find the two other major issues to contend with.

Karen explained: “The system accepts free form data input from EPC assessors, meaning there are data fields which we refer to as ‘messy’ – they contain a real mixture of information. It needs to be sorted into smaller, relevant sub-sets.

“The final issue is that core data and energy efficiency measures are missing from the Open EPC dataset or difficult to extract in their current form.” For example, property age is not included and the age of a home is a very important indicator of how the home has been built.

A very useful resource – potentially

Despite these factors, Karen thinks local authorities could find the information extremely valuable, if handled correctly.

She said: “If a local authority has its own experienced data team, to manage and present what’s downloaded, then they can get a really good picture of the housing stock in their local area. It can help target energy efficiency measures more efficiently with limited budgets.

“Also, they could overlay the housing data with those from the indices of deprivation to target those likely to be living in fuel poverty.”

Councils could also link Unique Property Reference Numbers (UPRNs) to the EPC data which would allow them to add in any addition housing information that they may hold. This could prove more than just practical for users of the data.

“If they can get an understanding of their local housing, it can be very useful in support of funding applications, which require good baselines.” Karen added.

It’s all in the interpretation

But it is very much a case that with this data, making sense of it is the most important thing if it’s to have a significant bearing on getting energy efficiency upgrades into homes. It must be made available in a way that’s useful to decision-makers.

Karen continued: “Previously we’ve heard from people who’ve paid for the data themselves and found it can be a bit of a nightmare to analyse. At Energy Saving Trust, we’ve had many years’ worth of experience handling housing data and have invested to establish the methodologies needed to present EPC data, and fill in missing data gaps.”

In short, free data is great, but it’s far from plain sailing from there on in. Sometimes it might be a good idea to call in the experts to extract the true value from data transparency.