British scientists developed a self-cleaning "smart window" that could cut heating costs by 40 percent. The smart window has microscopic, pencil-like structures engraved into its glass surface, which make it highly resistant to water.

The specialized surface make water roll off the glass like droplets, allowing these droplets to pick up dust, dirt and other impurities as they roll off.

The window has a very thin coat of vanadium dioxide, which acts as a heat loss-preventing system during cold months and helps bring down heating cost. During the hot months, the same coating prevents the sun's infrared radiation from seeping through, keeping the inside of the house or building cool.

Lead researcher Dr. Ioannis Papakonstantinou from the University College London said this is the first application of a thermochromic coating onto nanostructures, as these materials continue to be developed for other cleaning purposes. The pencil-like microscopic structure improves the properties of the coating, resulting in a high-performing, self-cleaning smart window.

Due to the many difficulties involved in cleaning a skyscraper's windows during its first five years, the current estimate of its accumulated cleaning cost is about the same as the price of its installation.

"Our glass could drastically cut this expenditure, quite apart from the appeal of lower energy bills and improved occupant productivity thanks to less glare," said Papakonstantinou, adding that using low maintenance glass is crucial as the architectural trend of using more glass continues. Depending on the amount of industry support, the new smart window could roll out into the market in just three to five years.

Engineering and Physical Sciences Research Council (EPSRC) chief executive Professor Philip Nelson said the smart window project shows that investments made in great research pushes innovation towards measurable benefits. Nelson gave £100,000 (over $141,000) as research fund.

The UCL research team is hoping to create a "smart film" where their nanostructures will be incorporated. The smart film can then be added to conventional windows in homes, factories, offices and other areas as a DIY basic. This will further lower energy cost, reduce light reflection and deliver the smart self-cleaning mechanism without affecting the architectural aesthetics.

The research was published in the journal Engineering and Physical Sciences Research Council on Jan. 20.