Retrofit is the introduction of new materials, products and technologies into an existing building to reduce the energy needed to occupy that building. Retrofit is not the same as renovation or refurbishment, which often make good, repair or aesthetically enhance a building without aiming to reduce its energy use.
 
The Retrofit for the Future programme explored how existing homes can be improved to use less energy, cut carbon emissions and save costs. The £17m programme, funded by the Technology Strategy Board, has helped businesses discover new opportunities in the growing retrofit market. In 2009, funding of up to £20,000 was awarded to 194 project teams to develop a retrofit strategy. Up to £150,000 was then awarded to 86 of those teams to find out how their strategy would work in real homes: ambitious targets were set to reduce energy use and carbon emissions. This guide tells the story of 40 of those homes, offering useful information and guidance for any organisation considering a retrofit project.