Neil Jefferson, director of the NHBC and chief executive of the Zero Carbon Hub
While it’s still too cold to lay bricks, it might seem strange to raise the issue of overheating in buildings.
But, anticipating warmer weather ahead, there is a real need for action now to stop the buildings we’re building becoming inhospitable in the future. First, we need to define the problem.
Overheating is caused when homes struggle to expel heat, often built up as the result of a mixture of normal occupant activities and high external temperatures. It is found to be an issue not just confined to a few hot summer days, but something that potentially affects homes for longer periods.
Reported cases of overheating in existing homes are still relatively low. However, a combination of features including enhanced construction methods such as higher standards of airtightness and increased thermal insulation in new-build homes are causing indoor temperatures, in some instances, to reach uncomfortable levels during summer. And for vulnerable groups, such as the elderly, overheating in homes poses significant health risks.
Considering impact and health concerns, a national definition of overheating in dwellings is called for. This will enable planners, designers and authorities to tackle overheating while striving to build and deliver more energy efficient homes.
Good design that can be put into practice successfully can go a long way to helping reduce the potential for overheating. Understanding the ability of achieving good cross-ventilation on urban sites where noise and security affect occupants’ willingness to open windows is key. It is also improtant to manage risks created through the drive towards zero carbon, such as communal heating pipework that is permanently hot, as well as ensuring that ventilation controls are clear and easy to operate.
With the combined effects of increasingly energy efficient homes, predicted rises in UK temperatures, increasing urbanisation and an ageing population, it’s highly likely that in the future, the number of reported cases of overheating will increase if this problem is not tackled head on today.