Melting Surfaces

New Commercial and Residential Low-E Windows May Melt Nearby Objects

Windows reflect a certain amount of heat. When the reflected heat surpasses a certain level, it can cause damage to plastic surfaces nearby such as vinyl siding, composite decking, patio furniture, and plastic automobile trim. Lawns, turf, shrubs, and other landscaping are also susceptible to damage.

According to the Department of Energy, approximately 80% of residential windows and 50% of commercial windows sold annually feature a low-emissivity (Low-E) coating. A Low-E coating makes a window more energy efficient but also reflects more longwave infrared (IR) energy and shortwave ultraviolet (UV) light. It is the increased IR and UV energy that can cause damage to objects nearby.

In addition to a window’s Low-E coating, another cause for melted surfaces is that double pane windows may warp due to changes in barometric pressure between the glass panes and outside air pressure. Once warped, the glass forms a slight curvature that concentrates the sun’s rays onto nearby surfaces similar to that of a magnifying glass. This concentration can cause temperatures of 200° Fahrenheit, well above the requirement to cause damage to plastic surfaces and nearby turf.

A window’s Low-E coating and curvature aren’t the only causes of damage. The National Association of Home Builders (NAHB) cites several other contributing factors:

Angle of the sun relative to the horizon
Proximity to neighboring buildings
Wind speed
Air temperature
Presence of buffering foliage

Reduce Melting and Other Damage Caused by the Sun with 3M’s Exterior Prestige Series Window Films

3M’s Exterior Prestige Series Window Films reduce the amount of the sun’s incident energy that is transmitted through the glass pane of a window by increasing the amount that is reflected and absorbed. What is absorbed is part of the sun’s longwave IR before it hits the Low-E coating to be reflected back outside. In addition, 3M Exterior Prestige Window Films reduce, but not eliminate, the intensity of the concentrated energy that is reflected from a window’s curvature.

While 3M’s Exterior Prestige Window Films have successfully reduced or eliminated the damage caused from Low-E windows and curved glass, there are a variety of other factors, such as those listed above, that will ultimately determine whether 3M Exterior Prestige Series Window Film is a viable solution for any particular situation. As such, the elimination or reduction of damage is not guaranteed.