Double glazing is the glazing process in which a window is made with two panes of glass with a space between them. The space between the glass is usually between 0.63 and 0.75 inches (16 and 19 mm) wide. In many cases, air is trapped between the panes and forms a layer of insulation. Before the unit is sealed, a drying agent is added to ensure that no moisture is present inside the finished glass unit.
Windows of this type must be airtight. If condensation appears between the panes, it indicates that there is a leak somewhere. These windows cannot be repaired; if condensation appears, the unit must be replaced.
Around 60% of heat loss in the home occurs through standard, single pane windows. Double glazing substantially stops heat loss, and the cost of the windows will often pay for itself very quickly in the money homeowners save from heating bills. Once the windows have been installed, heating costs should decrease by around 10 to 12%.
Double glazing is also very friendly to the environment. Homes cause around 28% of all carbon dioxide emissions, and replacing single pane windows helps to reduce these emissions and combat energy loss. As well as saving on heating bills, these windows are very good at cutting down on noise pollution and internal condensation.
Another reason to have this type of window fitted is the security it provides to a home. The main entry point for an intruder is through windows and doors. Double glazed windows provide extra security, as they are very hard to break and have their own locking system.
Double glazing also usually enhances the appearance of a property. There are a number of styles to choose from in terms of frames for the glass, including unplasticised polyvinyl chloride (UPVC), aluminum and hardwood. UPVC has better insulating properties than aluminum, but aluminum may be more aesthetically pleasing in older properties. Frames come in a wide range of color options.
With such windows, homeowners also have the option of secondary glazing on their existent windows. A house may have sound windows, but the owner may want to have the benefits that double glazing can provide. This can be achieved by fitting an extra glazed window internally against the original window. This can be a cheaper option than having a whole unit fitted and will keep the former look of the windows intact, as the secondary glazing is fitted internally.