Your Invisible Barrier

When you consider energy efficiency, perhaps the most critical part of any window is the insulating glass system. It only makes sense: the glass has the largest surface area.

Windows Can Help

To understand how windows can help, you must first understand that energy is lost through windows in three major ways: conduction, convection and radiation.


The framing of all Windgate windows is made from vinyl, a natural insulator. To prevent energy loss through conduction, all insulated glass units utilize Duralite© “warm edge” technology. Using a low-conductance spacer, this method assures maximum resistance to energy flow.


Energy can also be lost through natural convection currents that can form within the insulating glass. That’s why Windgate® glass is 3/4″ thick, shown by government testing to be the optimum dimension to prevent these convection currents.


Radiation occurs when long wave heat energy moves toward cold areas.

The most effective barrier to radiation is an optimal special Low “E” coating, a standard part of our InnovativE® glass.

This special coating actually reflects the long wave radiation back to its source.

This is important to understand, as radiation affects energy consumption, no matter what part of the country you call home.

Solar Gain vs. Heat Loss

The concerns of home owners in the North are quite different than those in the South.

In the North,where heating is a concern, glass must allow maximum solar gain, while preventing heat loss.

The Hawthorne Patio Door: Efficient

Dual Glazed 366 Glass Triple Glazed 366 Glass
U Value 0.27 0.26 0.17 0.16
Solar Heat Gain Coefficient (SHGC) 0.32 0.21 0.28 0.19
Air Infiltration 0.09 0.09 0.09 0.09

The InnovativE® Glass Package comes standard with double strength glass, Low E coating, Duralite® spacer and argon gas fill.

Triple glazed doors will have a U-channel steel spacer.

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