Is your vinyl siding melting? This is becoming a huge issue all around the country, and it seems that windows are to blame. Particularly the Low-E coating that is used in the production of energy efficient windows. Low-E windows are a valuable tool in helping to reduce the amount of energy to heat and cool homes. The Low-E coating is applied between the two panes of glass and stands for Low Emissivity. The coating is actually a metallic coating that helps increase a home’s energy efficiency by reflecting the heat back in the direction in which it comes from. This helps with cooling a home in the summer by reflecting the sun’s rays back out into the atmosphere, or more specifically, your yard.
As good as window manufacturers have become, some Low-E windows will have some degree of concavity to the glass which can focus the sun’s rays much like you did when you were a kid with a magnifying glass and dried leaves or bugs if you were more like my son. The temperatures that result from the increased reflectance of the windows coupled with the concavity of the window can result in high temperatures in small focused areas that may fall on materials not designed to withstand such temps.
There have been reports all over the country of vinyl siding melting on the North sides of houses due to the Low-E windows on the south side of the adjacent house. The phenomenon occurs any time of the year when the sun is at its highest, just before and after noon. The resulting temperatures can be in excess of 165 degrees F which is hot enough to melt most plastics. There have even been reports of fires as a result of the focused rays on cedar siding.
This past June in North Carolina in the Research Triangle area, NBC reported on public hearings being held to amend the International Building Code to address the problem because they had experienced so many incidents of melting siding within their jurisdiction (https://chatham.mync.com/site/Chatham/news/story/52740/state-now-investigating-melting-vinyl-siding-code-could-change/). Since the new building codes require the energy efficient windows, builders and remodelers are left scrambling to try to find a solution to the growing problem. And since the problem only occurs at certain times of the year and at certain times of the day, you almost have to be a forensic expert to put all the pieces together to come up with a solution.
In some cases, planting large shading trees has been suggested which works if the offending windows are near ground level. However, since the window can be on the second or third floor, screening with plantings is not always the solution. Awnings can help as well as installing full window screens which help cut down on the reflectance. Another possible solution is which side of the inside of the double pane glass that you have the Low-E coating applied to. The installation of replacement windows is now becoming a science!
A great YouTube video on the subject with plenty of pictures of melted siding can be viewed at https://www.youtube.com/watch?v=qdn2HrAWnyE. Good video, however, I must say I don’t advocate the rock throwing idea he includes at the end.
Homes aren’t the only structures affected. In a recent article in the Las Vegas Review-Journal, Joan Whitely tells of a humorous story of a man staying at the new Vdara Hotel in Vegas (https://www.lvrj.com/news/vdara-visitor—death-ray–scorched-hair-103777559.html). The building is a LEED certified structure with lots of glass. The concave, south facing structure has a pool in the center of the buildings arch. This pool happens to be at the focal point for all the glass windows. The man staying at the Vdara, visited the pool just before noon and was lounging poolside when he felt is scalp burning and smelled his burning hair. He jumped up and ran for shade at the poolside bar. The employees affectionately refer to the phenomenon as the Vdara Death Ray. The temperatures are so hot that the resulting hot spot melted the plastic shopping bag he had left behind. The employees said that guests regularly return to their chairs to find their plastic drink cups melted away. Seen any death rays in your neighborhood? Let me know @ info@DanGuinnHomes.com.
