Energy efficient windows blamed for scorched furniture

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By Jennifer Thomas By Jennifer Thomas

PHOENIX -- They are designed to help keep your house a little bit cooler, but it turns out energy-efficient windows can focus the sunlight into a laser beam.

It is causing big problems around the country, including here in Arizona, where a couple actually caught it on camera as it burned its way across their patio.

John and Deb Strandquist’s small front patio is normally a shady spot to rest under the blazing Arizona sun in Green Valley.

The Strandquists recently discovered something was invading their oasis, leaving their patio cushions with blistering burn marks. They just couldn’t figure it out.

“I came out front and I noticed the stripes on here and my first thought was maybe the pest guy had sprayed it with something," John Strandquist said. "We had all kinds of theories going.“

Determined to find the cause, he set up his own sting operation.

“So I set my camera up ... and I was doing an exposure every five seconds and I just let it go," he said. "I would go back and finish my coffee and I would come out and it was like, 'Whoa, we got a new one.'”

What he saw when he edited his still images together was amazing -- bright reflections of sunlight on the wall opposite several small square windows. He watched as they worked their way down to the cushions and then literally burned their way across them, leaving yet another scorched stripe on the patio furniture.

Strandquist said he was amazed.

“But then when I did it and went back through the exposures, I was like wow, that is really cool,” he said.

Actually it was really hot, but it helped Strandquist find the source.

Turns out the double-paned, low-E windows had warped, creating a convex surface reflecting the sun back with a focus much like a magnifying glass.

And it is happening to windows across the country, not just here in Arizona. One woman described what is happeing to vinyl siding on houses throughout her neighborhood, “So I have a melting house, I don’t  know what  to do, I can't get any help.”

In Hollywood, Calif., it was the housing on a car mirror that took the heat. “It kind of looked like someone had taken a blow torch to my mirrors.”

And there are hundreds of YouTube videos showing similar cases in all parts of the country.

Some builders are covering the damage for homeowners and the window company came to the rescue in Green Valley, much to Stranquist’s delight.

“The company offered to replace them, and I said, 'Please do,'” he said.

Still, window makers, builders and siding businesses all say such occurrences are relatively rare and fortunately no fires have been reported because of the windows. But the more Strandquis thinks about what could have happened, the luckier he feels with just a few scorched cushions.

“I'm thinking I would be more concerned than I was,” he said.

If you hav noticed problems in your home, it pays to contact both the builder and the window manufacturer to see if there is anything they can do.

Many newer windows come with small channels to equalize the pressure and keep the double panes from warping.

Our sister station in North Carolina has covered stories there. Here are some links to their stories, as well.

Double-pane windows can melt more than vinyl siding

Melting vinyl siding tied to energy efficient windows