CHARLOTTE, N.C. -- The NewsChannel 36 I-Team has been looking out for a danger next door. It s one that many people aren t aware of.

NewsChannel 36 has received dozens of emails from all over the nation responding to our consumer investigation about double-pane windows that focus the sun's light.

The results can cost you thousands of dollars in damage.

Imagine a focused beam of light measuring hundreds of degrees in heat aimed at a home, a deck, or a car.

Heather Petrone doesn't have to imagine. She's seen it first hand.

It looked like somebody had taken a blow torch on my mirrors, Petrone said. The focused sunlight had apparently melted the side-view mirrors off of her Toyota Prius. At first she complained to her car dealer.

It didn't dawn on me at first, she said. The dealer explained there was no internal mechanism that could cause that type of melting.

Petrone lives in the Studio City neighborhood of Los Angeles. After some online detective work, someone in a car forum suggested she look into the phenomena of double-paned, energy efficient, lowe or low-emittance windows. These windows can warp inward, creating a concave lens focusing the sun's light on nearby surfaces and acting like a magnifying glass.

That's when Heather found the reporting the NewsChannel 36 I-Team produced two years ago posted on

I was so skeptical, Petrone said. I was like, 'yeah whatever.'

Then Petrone followed the hot, focused beam of sunlight upward from her carport to the neighboring window.

I was like, oh my God! Really? she said.

Petrone called home inspectors who showed up with laser and infrared heat sensors to measure the beam. One device registered over 300 degrees Fahrenheit at 10 o'clock in the morning Pacific Time.

The double-pane windows acting as magnifying glass damage nearby property is a nationwide phenomenon still happening in the Carolinas.

And it's clearly not limited to vinyl siding but that's where many of the complaints start.

The vinyl siding is melting at Eileen Moore's six-year old home in Huntersville, NC.

But then why use this type of material down here or anywhere? Eileen asked. A homeowner can't replace all this.

Eileen replaced a section of vinyl siding once only to have the same spot melt and warp.

And nobody's going to buy it if I want to put it up for sale, she says of her damaged home.

The chairman of North Carolina's Building Codes Council, Dan Tingen, himself a Raleigh home-builder, says the problem extends nationwide. This has to be addressed on a national basis, Tingen said.

The NC Building Codes Council sets the standards for building products used statewide in North Carolina and a committee of the Council has been looking into the problem for more than a year.

The Council has heard from both the Vinyl Siding Institute and the window manufacturers represented by the American Architectural Manufacturers Association.

Tingen says one challenge is that building codes increasingly require builders to use the double-paned, energy efficient windows because they save on energy costs.

We are now mandating that builders buy these types of windows and with a window there's a good chance in a vinyl neighborhood you're going to have these types of incidents, says Tingen. There's not an easy solution.

The State of Massachusetts alerted the public about the problem of vinyl siding distortion, and Lawrence Berkeley Labs in California has begun studying the problem.

Neither the vinyl makers nor the window manufacturers have engineered a permanent fix.

You've got to understand their legal departments are sitting in the back room over there being very cautious about what they say because we all understand class action lawsuits, said Tingen.

But inquiries at the Vinyl Siding Institute as well as the American Association for Justice, a group of trial lawyers who typically bring such lawsuits, have not turned up a single case.

As energy-efficient, double-paned windows are used more often, complaints have shifted from vinyl siding to cars and other products.

But so far Tingen says there's been no evidence of fires. If there are instances like that, it would be a much larger concern, he said.

Eileen Moore says her home's warranty has not covered the window and siding problems. They were all out to make money and forget about the little guy, she said.

What should homeowners do?

Document the damage. Take photos and make a note of the date the damage appeared.

Check your warranties. Newer homes especially may still be covered, but don't bet on the warranty covering repeated damage.

Block the sun with a screen or awning over the window or with a plant or tree.

Admittedly, these are temporary fixes. The I-Team has been following the issue for two years and we'll keep investigating the issue until we learn of a permanent solution.

Meantime, feel free to send us an e-mail with your digital photos. Our email address is

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