The government has launched a public consultation on a radical new UK home energy rating system to replace the long-standing Standard Assessment Procedure or SAP rating.

SAP is the government’s current system for assessing and comparing the energy performance of homes. It is used in building regulations, to ensure new homes are energy efficient and low carbon and is used to generate Energy Performance Certificates, which have become increasingly controversial in recent years. 

SAP is also used more widely within and outside government, for example in government grant schemes, policy evaluations and to support advice to households on making energy efficiency improvements. 

The proposed new energy rating system – called the Home Energy Model – its regarded by some as more suited to the technologies required to decarbonise the country’s housing stock in a bid to achieve net zero.

The Home Energy Model has been designed by the Building Research Establishment (BRE) ahead of the implementation of the Future Homes Standard, which will apply to new homes built from 2025. 

The Home Energy Model will be used to set standards for new homes to ensure that they will be ‘zero carbon ready’, future-proofed with low carbon heating and high levels of energy efficiency. 

The government has also signalled its intention to use the Home Energy Model to power assessments for Energy Performance Certificates in the long term.

A statement from the BRE says the Home Energy Model is better suited to green technologies, such as heat pumps, storage technologies and smart control devices. 

It is designed to work in a modular way to support many different applications where energy performance assessments are required. It has a higher time resolution and can model energy performance for every half-hour of the year, enabling better representation of smart technologies and storage. The consultation proposes that the Home Energy Model will be released as open source, increasing transparency and making it easier for industry and researchers to apply and modify the methodology for different applications.

Gillian Charlesworth, the chief executive of BRE, says: “The introduction of the Home Energy Model is a significant milestone on the road to achieving net zero across the UK’s housing stock. 

“As uptake of green technologies increases, an effective assessment methodology which accounts for these changes will be imperative as the Government looks to secure buy-in from homeowners, house builders, and the retrofit industry on the net zero transition and achieve its targets in this area.

“BRE has worked closely with government since SAP was introduced, and we are excited about the potential for ambitious policies and programmes for low carbon homes which the latest version will support. These changes to the SAP methodology will have wide-reaching impacts not only for government, but across industry. I therefore urge all relevant stakeholders to take part in this consultation to ensure that the final design of the Home Energy Model is as well informed as possible.” 

The consultation opens this week and will close on March 6 2024.  You can see the government consultation here.