With a fair amount of buzz recently about how some energy-efficient windows can create a laser-beam effect that warps siding on a neighboring house, we thought we’d check into the hubbub.

Bottom-line: It doesn’t mean you should abandon your decision to invest in low-e (low-emissive) windows, which limit heat transfer so that your house stays cool or warm. In fact, some areas require low-e windows on new homes or in retrofits.

Anyway, the melting tends to occur under a perfect storm of conditions — so not very often.

Still, we’ve got some tips for you, below, in case your window or your neighbor’s window has turned into a ray gun.

Probably a more important issue is whether you need to replace your windows at all. Our guide can help you make that decision.

What Causes the Laser Beam?

Here’s one theory from the National Association of Home Builders (NAHB): Changes in barometric pressure can sometimes cause low-e windows to bow inwards and magnify reflected sunlight. It’s like training a magnifying glass on an ant; the heat beam toasts anything in its path to more than 200 degrees Fahrenheit. Vinyl siding starts to warp at around 165 degrees.