A new innovation will add to the energy-saving potential of buildings, with the addition of technology to normally drab drapery.

Electrical engineers have announced the invention of ‘smart curtains’, which react to sources of light and heat to provide the optimum blocking potential.

The curtains are imbued with carbon nanotubes which respond to light and automatically pull closed when the sun is at its brightest.

The carbon nanotubes are built up in layers glued to a plastic polycarbonate membrane.

As they absorb light and convert it to heat, the polycarbonate backing bends and re-shapes the curtains to block further heat from entering the windows.

“The advantages of this new class of photo-reactive actuator is that is very easy to make, and it is very sensitive to low-intensity light,” says associate professor of electrical engineering and computer sciences at University of California, Ali Javey.

“The light from a flashlight is enough to generate a response. We envision these in future smart, energy-efficient buildings. Curtains made of this material could automatically open or close during the day. During testing, the smart curtains have already proven to be highly sensitive and react to even low intensity light, which would make for the best energy efficiency.”

The curtains use no electricity, batteries or computing power, their passive design making them extremely cheap to run.