Emissivity in Single Vs. Dual Glazing

Heat Transfer

• Window glazing is a building practice designed to cut heat transfer through windows, where builders use double glass windowpanes to cut emissivity. Reducing heat transfer can save energy costs, because the heating or air conditioning unit does not have to work as hard to counteract discrepancies in the building's temperature, caused by heat entering and exiting the windows. The unit consumes less fuel, saving money. Dual glaze windows do not let as much heat pass through as single pane windows, according to the Lawrence Berkeley National Laboratory. The actual temperature of the single pane window during the winter is only somewhat higher than the outside air. Windows often have energy ratings that let homeowners know the extent that the window prevents heat transfer.

Inert Gas

• Double glazed windows have two panes of glass with a gap between them, which creates an insulation barrier. Single glaze windows do not have the space to create the extra barrier. Dual glaze windows sometimes have gas between them, which inhibits the passage of heat. These gases can be krypton, argon or xenon. When the space between the two panes of glass is vented, the window cannot contain inert gas in the space, since the gas will leak out. This reduces the window's insulation properties.

Carbon Output

• Since the dual glaze windows use up less energy, and since fossil fuels that power heating and cooling appliances release carbon emissions during combustion, dual glaze windows have a smaller impact on the overall global carbon output, which some scientists fear contributes to global warming.

Comfort

• During the winter, areas near windows can develop uncomfortable cold spots where heat escapes through the window. Dual glazed windows minimize these cold spots. Also, windows let sound waves travel through them. Dual glazed windows block more sound waves than single glazed.

Affordability

• Single glaze windows are cheaper than dual glaze when the homeowner also uses curtains to block heat transfer. Single glaze windows cost less to repair when broken. Otherwise, dual glaze are more economical in the end, due to lower energy consumption.