According to You Tube:
“In neighborhoods across America, there’s a strange phenomenon happening that’s melting paint, siding, pool covers, and car parts. It’s a problem that even caught the attention of the Department of Energy.
The vinyl siding on Lynne Loudon’s home survived 20 years of hail, rain, wind and sun. So, she couldn’t figure out why it suddenly started melting.
“I thought maybe it was lightning or because I bought a new microwave,” Loudon said.
Over time, the melt zone got longer and wider leaving Loudon to think her house was shifting. Something else was shifting up above in the sky.
“Came out one day and noticed like a spot of light, like yellow light and it was coming from the window,” Loudon said.
Loudon wasn’t seeing things. A neighbor saw it too.
“It was just a bright circle with an X in it,” Kathy Stec said.
Loudon and her neighbor agreed that the bullseye of sunlight appeared to be reflecting off the new, double-hung windows added next door. They’re energy efficient with a low e-glass coating. This means they reflect sunlight in the summer and keep the heat inside during the winter.
Vinyl Siding Institute says it’s not just siding that’s melting
The National Association of Home Builders says the curvature of the glass in the double hung windows can create a magnifying glass effect that focuses a light beam at other surfaces that can reach 200 degrees.”