5 On Your Side

State offers builders alternative to Low-E glass

Posted June 16, 2014

A WRAL News investigation into windows that reflect sunlight like a big magnifying glass has the state considering a change to the building code.

State building code requires Low-E windows for their energy-saving benefits. They have a coating that reflects the sun, keeping it cooler indoors. But the reflective quality has proven so strong that it melts vinyl siding and parts of cars. There are even reports that reflections from the roofs of sunrooms started fires on cedar shingles on at least four homes across the country.

Dan Tingen, chairman of the North Carolina Building Code Council, said his group spent more than a year looking into complaints that the windows were doing damage, but they hadn't reached a solution until the WRAL News report upped the ante.

"That was a concern, we just couldn't document it," Tingen said.

The reported fires raised the level of concern, and the council adopted an emergency rule as a first step toward change, Tingen said.

"It gives the builder the option of using non-reflective glass in locations that he can anticipate having a problem," Tingen said.

Low-E windows make up more than 90 percent of all new installations. In Knightdale, residents reported home after home after home with melted and warped vinyl siding.

"We certainly wouldn't have parked our vehicles here if we had any kind of warning," said Michelle Curtis.

"When things get really, really dry, and you've got a temperature high enough to bubble plastic on that young lady's car, that's pretty intense heat, and it wouldn't take much more to get pine straw or some other sort of mulch around the house to catch fire," Tingen said.

The window industry opposes the change. In a letter to the state Building Code Council, representatives wrote that it will have "a long-term negative impact on energy efficiency."

No one from the Window and Door Manufacturers Association answered calls from WRAL News for their solution.

The rule could take effect July 1.

For homeowners, the windows cost about the same whether they are Low-E or not.


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  • denisdh Jun 17, 2014

    Wish Raleigh's setback was 20ft instead of 10. Could help

  • SheriffTruman Jun 17, 2014

    Here is an idea. Install screens! We had screens installed in all of them when our houses were new. A few have removed them for whatever reason and a couple have caused issues for neighbors. The screen seems to shade just enough of the sun to make a difference and I am sure they could design screens that worked even better.

  • Brian Hill Jun 17, 2014
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    Except these don't actually save you money. Any savings you get from reflecting light in the summertime will be offset in the winter by the reduction of solar heating in the home.

  • busyb97 Jun 17, 2014

    We had these windows, and I am sorry, but they were NOT all that energy efficient. In the winter, you could feel the cold air all around them (not just the sides, but at the glass). My heating and cooling bill would argue about their efficiency for sure! And add on top of that the siding on my house that got melted (had 5 windows total that the builder replaced over the 6 years...and the siding that was near them on outcrops on the house).

  • James Bognar Jun 17, 2014
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    If safety were the only consideration, we'd all be driving around in tanks. Or we'd all be wrapped in bubble wrap at all times.

    Energy efficiency saves money and resources. That has a ripple effect (lower bills, more money spent elsewhere in the economy, less reliance on foreign resources, etc...).

    Safety is important, but it should never be the ONLY consideration.

  • Copper4 Jun 17, 2014

    Original report said that it was the Low-E coating combined with the concave shape of some windows. You have to have both issues for it to be a problem.

  • "Screen Name-8/20" Jun 16, 2014

    "The window industry opposes the change. In a letter to the state Building Code Council, representatives wrote that it will have 'a long-term negative impact on energy efficiency.'"

    And that's more important than people's safety???
    How exactly???