Simulate Low-E Glass

What Is a Low-E Window?

A Low-E window provides energy benefits year-round. That’s because it not only helps to reduce solar heat gain in the summer, but also heat loss in the winter, thanks to an extra metallized coating added to the glass during the manufacturing process. This added benefit is particularly useful in northern climates during the fall, winter, and early spring months. Homes and buildings with Low-E windows typically consume less energy for heating as compared to similar homes and buildings that do not have Low-E windows.

Why Are Low-E Windows Important?

Simple science tells us that heat travels from places of hot to cold. As such, the heat generated from an HVAC system (furnace, boiler, etc) wants to go where it’s cold, which is outside where it is significantly cooler. That heat travels outside through the path of least resistance, which is typically through a window (as well as other parts of the building envelope). The metallized coating of a Low-E window increases the resistance of that heat to pass through the glass by reflecting it back inside, thereby reducing the amount of heat that is lost to the outside. Reducing heat loss means that the HVAC system consumes less energy which lowers heating bills (gas, electric, steam, oil).

Do I Have Low-E Windows?

Newer homes and buildings typically have Low-E windows, especially where required by local code, but there are two ways to know for sure:

Check the lower right or left corner of the glass for the appropriate indication
Use a commercially available Low-E coating detector

A common misperception is that all double or triple pane windows are Low-E units. They are not.

What Is Low-E Window Tint Film?

Imagine taking the same Low-E coating found on a Low-E window and applying it to a piece of clear polyester that is then installed on regular window glass. That’s exactly what Low-E window film is.

Low-E window tint, or insulating window film, is a retrofit polyester film with a Low-E coating that is applied to an existing window to make it a Low-E window. It is much easier and more cost-effective to turn an existing window into a Low-E window using special polyester film than it is to replace it. Window replacement is costly and disruptive to occupants, tenants, and residents.

3M Company has been manufacturing Low-E window films since the early 1970s, helping buildings and homes reduce their heating consumption during winter months. Lowering heating consumption helps building owners and homeowners reduce their carbon footprint by relying less on heating fuels such as gas, oil, electric, or steam.

Not only does Low-E window film help to improve the energy efficiency of a window during the winter months by reducing heat loss, but it also helps during the summer months by reducing solar heat gain, saving you money year-round. In technical terms, a Low-E window tint reduces a window’s U-Value as well as its Solar Heat Gain Coefficient (SHGC). A reduction in SHGC translates into air-conditioning savings while a reduction in U-Value translates into heating savings.

Cooling Season

During the cooling season (hotter months), window film increases the amount of the sun’s incident energy that is reflected and absorbed by the glass, thereby reducing what is transmitted into the building.

Heating Season

During the heating season (colder months), window film increases the amount of man-made heat from the HVAC system that is reflected back inside the glass, thereby reducing what is lost to the outside.

At a Glance