ConsumerWatch: Energy-Efficient Windows Blamed For Melting Neighbor's Car

BERKELEY (CBS 5) - A California woman says the energy efficient window installed in a neighbor's condominium is melting the plastic components on cars parked in her carport.

Heather Patron of Studio City was dealing with a mystery regarding her Toyota Prius.

"The side view mirrors were melting," said Patron. "Anything that was plastic on the car was melting."

Toyota told Patron nothing was wrong with the car. After having the mirrors replaced, she noticed the mirrors on the car parked next to hers were also melting.

Patron then observed a powerful beam of light that was reflecting off the window of a next door condominium, casting a concentrated beam over her carport.

A thermometer placed in the path of the beam on a partially cloudy day registered the temperature at over 120 degrees in less than five minutes.

"I'm positive that this window is what is causing the damage to my car," said Patron.

Robert Hart, Scientific Engineer at the Lawrence Berkeley Lab, explained a normal window reflects anywhere from 10-13% of the suns rays. By contrast, the LEED certified windows that are currently being installed in most new buildings have a highly reflective coating that deflects up 40% of the sun.

Adding to the issue is the angle of the glass. "The window will never be totally flat because of the trapped air inside of two glass panes," said Hart.

When it's cold outside, the pressure within the double-paned window creates a concave piece of glass which magnifies the suns rays. Combined with just the right low winter sun angle and the high reflectivity of these energy efficient windows, a beam of light is created that is strong enough to melt plastic.

Hart said most of the reported cases have occurred on the East , melting vinyl siding.

He was surprised to hear about the melted mirror in California, however Heather Patron suspects her case won't be the last.

"I just don't feel like it's fair," said Patron. "I feel like it needs to be known that this is happening. And a lot of people probably have damage out there…they aren't aware that it's the windows that are causing this."

The National Association of Home Builders is now conducting a study on the matter.

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