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Double glazing works by trapping air between two panes of glass. This trapped air creates an insulating barrier which provides three functions. First of all it prevents heat loss or gain through the window because the barrier insulates the room from differing air temperatures at either side of the glazing unit. Secondly, double glazing helps keep noise pollution down. The third benefit of double glazing is that it helps reduce condensation. Condensation commonly occurs on the inside of single glazed windows due to the warm air inside the house being cooled by the cold outside air. With a double glazed window the insulating barrier prevents the transmission of air temperature and therefore prevents condensation occurring.

Although double glazing insulates against differing air temperatures, it does not insulate against radiant heat. This makes a double glazed unit a good choice for permitting the winter sun to warm the inside of the house. 

Why are the double glazed units filled with Argon gas?

An improvement that can be made to the thermal performance of insulating glazing units is to reduce the conductance of the air space between the layers of glass. In most double glazing units, the space is filled with air or flushed with dry nitrogen just prior to sealing. In a standard sealed glass insulating unit, air currents between the two panes of glazing carry heat to the top of the unit and settle into cold pools at the bottom.

Filling the space with a less conductive, more viscous, or slow-moving gas such as Argon minimises the convection currents within the space, conduction through the gas is reduced, and the overall transfer of heat between the inside and outside is reduced. This phenomenon results from the fact that the density of the gas is greater than the density of the air.

All of the double glazed units we use at Bond Homes are filled with Argon gas*. This type of double glazing has a marked improvement, (up to 30%) in thermal performance over standard double glazing.

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