Advanced Open EPC

About the project

The current Energy Performance Certificate (EPC) system is criticised for being inaccurate, sometimes as a result of incorrect input data but also because the assumptions are standardised across all homes, for example assuming all homes are heated to 21°C. The role of an EPC is rapidly changing in response to widespread heat pump rollout and the need for widespread retrofitting and consequently what is needed from an EPC is shifting. This Advanced Open EPC project seeks to understand, through engagement with industry leaders, what future EPC reports should look like.

What has the project successfully delivered?

The Advanced Open EPC project aims to develop a tool that allows building owners and users to understand the energy performance of their building in a way that is more accurate and more useful than the current EPC system. The solution will involve a home survey that takes in more information than a current EPC survey combined with in-home measurements to understand the heat loss rates of the building through existing SMETER technology.

Next steps

In this project, the team have built a retrofit recommendations tool based on the first release of the Home Energy Model. On their online platform (which is not yet publicly available), users put in an address and information from any existing EPC is pulled through. Users can then update the information on the page (wall types, insulation levels, heating system etc) and provide a budget for energy saving works. The tool then uses the input information to run the Home Energy Model. The user is then provided with retrofit options for the property, showing the costs, fuel bill savings, emissions savings and impact on the EPC rating.

City Science are working on three key next steps in this project:

• To capture more information about a home in the EPC survey in a way that is easy to use and can be aligned with the inputs for the Home Energy Model.
• To integrate monitored data from homes into the tool to give the most accurate and useful information about the home while still protecting users’ privacy.
• To integrate that additional information about a home into the Home Energy Model and allow users to adjust assumptions that have a big impact on outputs, such as the temperature of the home and heating schedules.

What has the project achieved?

So far, the project has achieved integration of the Home Energy Model and data collection in a number of homes to support development of a monitoring solution that can be integrated into an EPC.

Key lessons learned

The team have built a model that can estimate the thermal performance of a building through smart meter data and in-home temperature sensors, which can provide significantly greater accuracy than a survey-based approach. The challenge that remains is how to incorporate this insight into the existing EPC report. Through the rest of the project, City Science aim to create a tool that lets building users understand their building and provide a solid evidence base for decisions on upgrades that can be made.

• Despite widespread criticisms, EPCs remain one of the few comprehensive sources of information on the UK housing stock. The team has identified that policy makers and analysts require accurate data for understanding the housing stock and setting targets, while homeowners and tenants need specific insights on the operational costs and potential upgrades for their homes. However, the current EPC system does not adequately meet either of these needs.
• The team has embraced the challenges of pioneering the Home Energy Model, noting the lack of existing data on how its outputs compare to the SAP model. This includes uncertainties about whether energy demand will increase or decrease and how these changes will vary across different house types and heating systems.

Project partners and subcontractors

Purrmetrix have supplied the in-home sensors and Building Performance Network (BPN) have provided support and insight on the methodology for measuring building performance and alignment with BS40101.