Will the green deal really make my home overheat?
Posted by Tasha Kosviner on 7 August 2013 at 9:06 am
You’ve got to pity the poor department for energy and climate change. No sooner have they announced a flagship green deal scheme to beef up our home insulation and make us all cosy and energy efficient then the weather goes and gets all hot and we all start opening the windows and switching on the electric fans.
And then, as if that’s not enough, an eminent scientist pops up to warn us about how the green deal has overlooked the fact that extensive insulation might actually make some homes OVERHEAT in particularly clement weather.
Now the scientist behind the recent headlines such as “Green Deal ‘could lead to deadly summer overheating’” and “OAPs could die in Green Deal homes” tells me that his findings should not put people off embracing the green deal.
“Ten times more people die from being too cold in the winter than from being too hot in the summer,” Dr Chris Goodier, of Loughborough University’s department of civil and building engineering told me this week. “Let’s be clear, for the majority of people, insulation is a good idea.”
But what about the minority? Who are they and how can they tell if they are at risk? Well here’s the rub.
“It’s very difficult to identify if you are in that minority,” says Dr Goodier. “But if a property is very air tight, with lots of glazing letting in lots of sun, with 10 people living in it who are there all day warming it up with their bodies then it is at risk of overheating. If that property is situated in the inner city surrounded by lots of heat absorbing concrete and no nearby trees or water to cool the environment down – that’s a property that could be in a very poor situation.”
Assessing the danger of overheating is not something a Green Deal assessor is necessarily equipped to do. Indeed as Dr Goodier pointed out, the effort and detail required to do all the necessary tests – such the dynamic simulation test – would stretch the budgets of many domestic homeowners simply looking for a bit of loft insulation to warm them up a degree or two over the winter months.
So would fear of overheating lead him to caution anyone against improving their home insulation?
Dr Goodier: “No. Insulation slows the rate of heat escaping from your home in the winter, and in the right conditions, can slow its rate of entering your home in the summer. So use your common sense. If you live in a house that gets very hot in the summer, then when you are investing in your extra insulation to protect you from the winter cold, consider taking other precautions: install external shutters or blinds to block out the sun, if planning permits it, consider painting your external walls white to reflect the sun – and if you get an occasional heatwave, be careful, open the windows at night, seek out the shade.”
Further measures, suggested by the sustainability writer, Roger Hunt, include retractable awnings, designing wider eaves on a new build, installing a pergola on a patio or - a long term solution this one - planting a deciduous tree close enough to provide some shade (but far enough away so the roots don't disturb the foundations of your building).
In a statement, the department of environment and climate change said: "DECC is working with experts and other government departments to understand the potential risk of overheating in retrofitted homes and ensure that the energy efficiency supply chain, including those working within the Green Deal, are aware and guidance is provided on homes which are most likely to be vulnerable and what steps could be taken to minimise any risk of overheating."
Earlier, Dr Goodier was quoted on the BBC news website as calling the danger of overheating, “the little boy at the back of the class waving his hand,” and warning that “if you are in the wrong type of house, facing the wrong way, in the wrong street and you don’t deal with heat in the right way, it is a problem. Particularly for the elderly. They are going to suffer. Suffering means they are going to die from overheating."
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