A window of opportunity! Self-cleaning smart panes inspired by moth eyes could cut heating bills by almost half

Smart windows that clean themselves could not only put an end to the tedium of wiping panes, but could significantly cut your heating bills too.

British scientists have developed the windows, which are ultra-resistant to water, thanks to pencil-like microscopic structures engraved into the glass.

Water simply rolls off the panes in spherical droplets, picking up dirt, dust and other contaminants while inadvertently cleaning the windows as the particles are carried away.

A super-thin coating of an inorganic compound called vanadium dioxide also prevents heat loss from the windows during cold periods, which, the inventors claim, could reduce heating bills by up to 40 per cent.

In hot weather, the film additionally prevents infrared radiation from the sun entering the building and raising the temperature.

'The bio-inspired nanostructure amplifies the thermochromics properties of the coating and the net result is a self-cleaning, highly performing smart window.'

Thermochromism is the property of substances to change colour due to a change in temperature, and the effect reduces glare.

The design of the nanostructures gives the windows the same anti-reflective properties found in the eyes of moths and other creatures that have evolved to hide from predators. 

It cuts the amount of light reflected internally in a room to less than five per cent, resulting in less 'glare' to make a room more comfortable.

Dr Papakonstantinou continued: 'It's currently estimated that, because of the obvious difficulties involved, the cost of cleaning a skyscraper's windows in its first five years is the same as the original cost of installing them.

'Our glass could drastically cut this expenditure, quite apart from the appeal of lower energy bills and improved occupant productivity thanks to less glare. 

'As the trend in architecture continues towards the inclusion of more glass, it's vital that windows are as low-maintenance as possible.' 

The scientists are in talks with UK glass manufacturers with a view to commercialising the concept. 

The first smart windows could reach the market in three to five years, depending on the level of industry support.

Professor Philip Nelson, chief executive of the Engineering and Physical Sciences Research Council (EPSRC) which contributed £100,000 to the research, said: 'This project is an example of how investing in excellent research drives innovation to produce tangible benefits.

'In this case the new technique could deliver both energy savings and cost reductions.'