BRE and Willmott Dixon project to retrofit of a 1920s semi-detached house

On 6 April 2016, construction and property services company Willmott Dixon announced a research project with BRE (Building Research Establishment) and the Letchworth Garden City Heritage Foundation to create a blueprint for improving the energy efficiency of older properties. Ref Project aims to help period properties save thousands in fuel costs.

By retrofitting a 1920s semi-detached home in Letchworth they will create a template for improving the efficiency and reducing the fuel costs of other pre-war homes.

The house is owned by the Letchworth Garden City Heritage Foundation, a self-funding charitable organisation, which uses revenue from commercial rents to re-reinvest in the town.

The house was first assessed to determine its baseline energy performance, then performance specification options were developed in line with current government regulations and more ambitious carbon and energy reduction targets.

The works, which are a compromise between improving the property’s energy efficiency and preserving its character, will include; installing wood fibre internal wall insulation, new windows, solar photovoltaic (PV) panels, waste water heat recovery and demand-controlled ventilation.

Its performance will then be monitored for 12 months to determine its energy use, internal conditions, the performance of its design features and the experience of its residents. A similar unmodified property will also be assessed to provide a comparison. It is hoped that the results will help develop a rationale for investment in the retrofit of other heritage and older properties.

BRE project manager Steven Stenlund said, “The aim of this project has been to plug the knowledge gaps on how best to make heritage homes like these more energy efficient without compromising on their unique character. The learning derived from the demonstrator home will benefit local homeowners and will have broader national applications as we continue to drive down the energy use and carbon emissions from existing homes.”

Willmott Dixon’s Rob Lambe said, “With over a quarter of the UK’s total carbon emissions coming from our homes and a fifth of households living in fuel poverty, it’s really important to ensure domestic properties are as energy efficient as possible. With a large number of older and heritage properties in the UK, there is a particular need to explore a range of options that will help people to keep warm and save energy while protecting the characteristics of these buildings.