Low E is an invaluable material designed to reflect heat. Did you know that in most homes, the registers or heat vents are purposely located beneath the windows? The reason the builder of that home did that, was because the walls are considerably warmer in the wintertime than the window. So in order to compensate for the heat loss the builder would place the vents in front of the windows in order to warm that area. The problem is, as the heat rises from the vent, it literally rises up and escapes through the window. Heat always gravitates to colder temperatures.
Low E is so efficient that it reflects heat as quick as a mirror would reflect your own image. That allows your furnace to fill your home with heat much faster and allows the furnace to stay off much longer once the home has been heated to the required temperature.
In the Summertime. Low E works just the opposite. The outside summer heat is reflected back into the atmosphere , allowing your air conditioner to cool much faster and to stay off much longer. Not only does the consumer save money on utilities , but also the unexpected benefit of prolonging the life of the life of heating /AC system.