Homes insulated under the Green Deal scheme could be at risk of dangerously high temperatures during summer months, a university professor has warned.
Professor Chris Goodier from Loughborough University's department of civil and building engineering has acknowledged that it is vital UK homes are better insulated, to help cut fuel bills and meet UK carbon emission targets. However, he said that "in the big rush to insulate and make homes airtight", the risk of overheating has been overlooked.
This is of particular concern, he said, as meteorologists predict an increase of extreme weather events such as heatwaves.
"Overheating is like the little boy at the back of the class waving his hand," Goodier told the BBC News website. "It is forgotten about because the other challenges are so big. They are taking very effective measures to protect against winter temperatures but by doing that, they increase the risk of overheating."
In well-insulated homes, heat builds up during the day and has nowhere to go at night, leading to poor air quality and a greater risk of heat stress for the occupants. Research by the University of Reading supports Goodier's fears, suggesting that top-floor flats in tower blocks and south-facing modern detached houses are most at risk.
Research published in 2012 by a group of engineering and climate change experts has warned that increased numbers of summer heatwaves could lead to a rise in heat-related deaths from 2,000 per year to 5,000 per year by 2080, if action is not taken.
The Department for Energy & Climate Change (DECC) says it has now issued fresh guidance to Green Deal suppliers to help reduce potential risk from installing energy efficiency measures, as part of a broader plan to deal with the effects of climate change.
DECC released a statement saying: "The real problem facing our nation's draughty homes is a lack of adequate insulation and energy efficiency in the colder months. The Green Deal is giving households a new way to fund improvements, helping them protect themselves against rising energy bills and keep homes warm and cosy in the autumn and winter. If energy efficiency measures are installed appropriately, overheating should not be a common problem and there's guidance available for those involved in the Green Deal."