New research led by Leeds Sustainability Institute (LSI) at Leeds Beckett University and in collaboration with University of Salford and Loughborough University has found that insulating the UK’s eight million solid walled homes has the potential to cut energy bills by up to 30 per cent and is essential to achieve the domestic energy efficiency targets.

The researchers found that, whilst solid wall insulation may be expensive and complicated to install safely and effectively, it can bring many benefits to homes which include being cheaper to run, feeling warmer in winter and cooler in summer, having better air quality, and having less chance of condensation occurring.

The Energy House test facility at the University of Salford was used to assess the potential benefits of a whole house approach to retrofit against traditional piecemeal retrofit practice and was just part of a much larger project covering multiple retrofit case studies and involving hundreds of different tests, samples, surveys and modelling scenarios across England.

The £3 million Demonstration of Energy Efficiency Potential (DEEP) project was commissioned by the Government’s Department for Energy Security and Net Zero. Investigating the retrofit (making energy improvements in homes) of solid walled homes, it is one of the largest research studies of its kind to have ever been attempted in the UK.

The aim of the DEEP project was to investigate taking a system-level approach to retrofit, considering the entire dwelling rather than the performance of individual measures. Typically defined as a ‘whole-house’ approach, this appreciates the complex interactions between fabric, ventilation and the occupant.

The results from field trials, laboratory testing, and extensive modelling investigations have produced a series of complementary findings that paint a picture of performance and risk for piecemeal and whole house approaches to retrofitting solid walled homes.

Professor David Glew, Director of the LSI at Leeds Beckett University, said:
 

“Solid walled homes are among the least energy efficient – occupants are more likely to be in fuel poverty, and condensation, damp and mould problems can be common.

“Our research found that insulating the solid walls of a home could save up to 30 per cent per year for some homes on their energy bills. It was by far the single most effective retrofit measure for solid walled homes – other types of retrofit couldn’t achieve the required improvement – and so this will be essential for tackling fuel poverty.”

Dave Farmer, Research Fellow at the University of Salford, said:
 

“The research is the most in-depth case study to date into how retrofitting insulation can affect the heat loss from a solid wall house and the performance of its heating system. The findings demonstrate that current retrofit standards and practices can significantly reduce space heating energy use and CO2 emissions while also providing a healthier internal environment for occupants.”
 

Key links for more information:

Leeds Beckett University: Insulating solid walled homes has potential to cut energy bills by up to 30 per cent, major new research study finds >

University of Salford: Insulating solid walled homes can save on energy bills​ >

DESNZ: Demonstration of Energy Efficiency Potential (DEEP) >

DEEP: report 1: Synthesis >