How Do Dual Pane Windows Work?

Replacing old, single pane windows with energy efficient dual pane windows saves homeowners a substantial amount on electric bills. Poor-functioning windows contribute to 25 percent of energy costs. Dual pane windows use current technology and construction methods to decrease heating and cooling loss, allowing you to maintain comfortable indoor temperatures without extra energy costs.

Insulation

Dual pane windows feature two panes of glass, spaced ½ to ¾ inches apart, and set into a frame. Some manufacturers fill the space between the glass panes with an inert gas, argon, carbon dioxide or krypton to improve the window’s insulation factor. The gas reduces the amount of heat transferred through the window panes.

Low-E Glass

New dual pane windows often feature glass coated with a low-emissivity, or low-E, protective film. This coating of a microscopic layer of metal or metal oxide applied to the glass improves energy efficiency. Low-E glass keeps heat from transferring out of the house in the winter, and keeps hot air from infiltrating the home in the summer.

Window Frames

The materials and construction used in dual frame windows contribute to their increased energy efficiency. Frames made from vinyl, wood, vinyl-clad and fiberglass with thermal breaks placed between the material conduct less heat than outdated single-pane, aluminum framed windows.

Window Tint

Heat gain from sunlight accounts for approximately 30 percent of cooling costs. New technology gives the option to reduce solar gain with different window tints. Bronze and green window tint keep out more sunlight than clear low-E glass. Glass that is both tinted and low-E provides the most protection from solar gain during the summer months. Know that window tint can reduce your visibility through a window.

Placement

Proper placement of new energy efficient windows should reduce infiltration of heat and increase natural ventilation. Infiltration is the unwanted transfer of heat into or out of a window. Good ventilation allows hot air to escape in warmer months and reduces cooling costs.