An average home loses 10% of its heat through windows and doors. Good, energy efficient glazing reduces this heat loss, keeps the home warmer and reduces heating bills. It can also make the home quieter.
Double-glazed windows have two sheets of glass with a gap between them which is usually 16mm wide. It is this gap which creates an insulating barrier to slow down the rate at which heat escapes from the home. Triple-glazed windows are now also available which have three sheets of glass, and therefore two insulating gaps, to provide even better insulation.
How to choose a double-glazed window
Choosing replacement windows for a property can be a complicated process; there are many factors to consider including the type of glass, the window frame material and whether the windows are suitable for the style of property. Here are some tips you can follow when looking for replacement windows.
The most energy efficient glass for double glazing is low emissivity (Low-E) glass. This type of glass often has an invisible coating of metal oxide on one of the internal panes of glass next to the gap. The advantage of this type of glass is its ability to let light in but cut down on heat loss. In addition, the gap between the two panes of glass in very efficient double glazing is filled with an inert, non-toxic gas. This gas has a greater density than air, so it more effectively reduces the heat loss from the property. Argon is the gas most commonly used in double-glazed windows, as it is extremely cost-effective, colourless, is non-flammable and does not react to other gases.
When your windows are replaced it is important to make sure that the property remains well ventilated, as the replacement windows will be more airtight than the originals. Ventilation is necessary as it allows fresh air into your home, and allows moisture to escape. If your property does not have much natural (passive) ventilation, look for replacement windows which have trickle vents. These allow a small amount of controlled ventilation.