Bicester’s Garth House makeover cuts energy bills for a historic building

Monday, 25 January 2016

Garth House Bicester

A radical makeover of Bicester Town Council’s offices, Garth House, has achieved impressive savings in energy bills and halved the building’s emissions of climate-changing carbon dioxide, according to a monitoring report by Oxford Brookes University.

It has also made the council’s offices at the Garth more comfortable for council staff, with better ventilation and less overheating in the summer.

The project has demonstrated that it is possible to make significant energy-saving improvements in a historic building in continuous occupation.

Prof Rajat Gupta, Director of the Low Carbon Building Group, Oxford Brookes University

A major energy saving refit of Garth House was funded by the Department for Energy and Climate Change and administered by Innovate UK, a government agency which backs the development of promising new technologies for businesses of all kinds. The project was led by Bicester Town Council, and project managed by sustainability charity Bioregional. Ridge and Partners LLP were the architects while researchers from Oxford Brookes University’s Low Carbon Building Group monitored and evaluated the performance of the building before and after the refurbishment.

Professor Rajat Gupta, Director of the Low Carbon Building Group and Oxford Institute for Sustainable Development said: “We used a web-based remote monitoring system to assess electricity and gas use, indoor environmental conditions such as temperature, relative humidity and CO2 levels, and outdoor weather every five minutes for twelve months after the refurbishment and we found that the performance of the building met and exceeded expectations.

“There has been a 58 per cent reduction in annual energy use and a 48 per cent reduction in CO2 savings over the pre-refurbished level. Gas consumption has reduced by 67 per cent while electricity use has reduced by 22 per cent through a combination of energy-saving measures and users becoming more energy conscious because of the works.

“Overall, the project has demonstrated that it is possible to make significant energy-saving improvements in a historic building in continuous occupation.”

Several different techniques were used to reduce heat loss and improve ventilation in the poorly insulated and draughty Victorian building in Garth Park. None of them were allowed to change the external experience of Garth House, which was built in the 1830s as a hunting lodge and lies within Bicester’s central conservation area.

Among the most innovative of these techniques was WHISCERSTM – Whole House In-Situ Carbon and Energy Reduction System. This uses lasers to measure the dimensions of rooms within the building, with the measurements then being fed into a computer which controls a cutting machine. This cuts large pieces of indoor insulation panels into exactly the right shapes, so they join up to cover all of the exterior walls.

Other members of the team were the main contractors, Kingerlee Ltd and the WHISCERS installer was Proteam Asset Management Ltd. 
The Low Carbon Building (LCB) Group has an international profile in the field of carbon counting, building performance evaluation, post-occupancy feedback, low-carbon retrofitting and climate change adaptation of buildings and neighbourhoods.

LCB Group is a co-founder of the Eco-Bicester Living Lab initiative (with Bioregional, A2 Dominion and Cherwell District Council) and has been a key partner in numerous collaborative projects in Bicester, funded by Innovate UK programmes such as Design for Future Climate, Building Performance Evaluation, Invest in Innovative Refurbishment and Solving Urban Challenges with Data.

More information about the Low Carbon Building Group can be found on the School of Architecture webpages.  The full report can be viewed here.