These were amongst the key findings of a research project led by the National Trust, Redrow Homes and Bryant Homes which reviewed the delivery of sustainable housing at Stamford Brook in Altrincham, Cheshire.
As part of the project researchers from Leeds Metropolitan University recorded the actual energy performance of the new housing.
The final report said: “Ultimately, it has been concluded the volume house building industry will struggle to meet enhanced energy performance standards for reasons that are deeply embedded in the culture, processes and practice of all levels in industry.”
Researchers said the technology existed to meet higher performance levels likely to be introduced when Part L is reviewed in 2010.
But, the report added: “This assumes that actions are taken to tackle the issues that have been highlighted in this project such as thermal bypassing, heating system design and typical construction faults, and also to address underlying system and process failure.”
Suggested improvements included better insulation of pipe work. But, one of the most important findings at Stamford Brook was the heat loss due to unexpected “thermal bypassing” through the party wall cavity between attached dwellings.
This meant measured heat loss was higher in reality – in some cases 100 per cent higher – than predicted through modelling.
An in-depth draft report by the university – which is awaiting Government approval – said: “This is one of the most significant technical findings from the project since current design and regulatory practice assumes heat loss from party walls is insignificant and can be ignored in the calculation of dwelling carbon emission rates.
“However, the findings at Stamford Brooks have demonstrated the unaccounted heat loss can be very large. This has far reaching implications for regulation, the design of dwellings and energy modelling protocols.”
Delivering Sustainable Housing report
Leeds Metropolitan University report