Low Emissivity (Low-E) Glass - An Improved Energy Budget

We hear a lot about the rising costs of energy nowadays, and whilst some of the doom mongers may be annoying it still obviously makes sense to save energy whenever we can. And Low Emissivity Glass can help with just that, both in summer and winter.

To work their magic; low emissivity windows have in them various very nearly invisible coatings made up from a recipe of metal, metal oxide and metal nitride. These coatings prevent the glass from radiating (giving off) so much heat.

Where these low-e coatings are placed within the structure of insulated windows will affect the job they do.

The Low-E Effect

In hot climates where cooling costs need to be lowered the low-e coatings are placed on the inside surface of the outer pane of glass. This will help to prevent the external heat being transferred from the hotter outer pane to the cooler inner one, and subsequently radiated into the home. Low-e can also be combined with tinted glass for a better performance still.

Whereas in cold climates where it is not a question of keeping the heat out, but keeping it in; the emission stopping metal coatings are therefore on the outer surface of the inner window pane. This will prevent the warmer inner pane of glass from giving out so much heat to the colder glass pane on the outside of the window, where the heat will be lost from the home to the outside air. This coating will also bring a slight reduction in heat gain during hotter weather.

Alternatively the low emissivity coatings can be placed on the relevant sides of a plastic film between the window panes.

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Author Notes:

Anthony Lee contributes and publishes news editorial to http://www.replacement-windows-n-shutters.com. Find everything you need to know about replacement windows, shutters, tinting, basement, fiberglass windows and more.