Insulated glazing unit

1.  Call: 1300 812 201 One of the shortcomings of glass is its relatively poor insulating qualities. Multiple panes of glass with air spaces in between improve the insulating value considerably. Figure 3-5 illustrates the performance of single glazing with clear glass. Relative to all other glazing options, clear single glazing allows the highest transfer of solar energy while permitting the highest daylight transmission. Figure 3-6 illustrates the performance of a typical double-glazed unit with two panes of clear glass. The inner and outer panes of glass are both clear, and they are separated by an air gap. Double glazing reduces heat loss (as re?ected by the U-factor) by more than 50 percent in comparison to single glazing. Although U-factor is reduced signi?cantly, the VT and SHGC for a double-glazed unit with clear glass remain relatively high.     Edge Spacers The panes of glass in an insulating unit must be held apart at the appropriate distance by spacers. In addition to keeping the glass units separated, the spacer system must serve a number of functions:

2. accommodating stress induced by thermal expansion and pressure di?erences. providing a moisture barrier that prevents passage of water or water vapour that would fog the unit. providing a gas-tight seal that prevents the loss of any special low-conductance gas in the airspace. creating an insulating barrier that reduces the formation of interior condensation at the edge. Warm edge spacers have become increasingly important as manufacturers switch from conventional double glazing to higher-performance glazing. For instance, edge of glass e?ects are more important for smaller windows, which have a proportionately larger glass edge area. Gas Fills and Gap Width in Multiple-Glazed Units Another improvement to the thermal performance of insulating glazing units involves reducing the conductance of the air space between the layers. Originally, the space was ?lled with air or ?ushed with dry nitrogen just prior to sealing. In a sealed-glass insulating unit, air currents between the two panes of glazing carry heat to the top of the unit along the inner pane and settle down the outer pane into cold pools at the bottom. Filling the space with a less conductive, more viscous, or slow-moving gas minimizes the convection currents within the space, reducing conduction through the gas and the overall heat transfer between the interior and exterior. The use of low-conductance gas ?lls is far less common in commercial glazing than it is in residential windows. This results from the fact that solar control technologies are more important in typical commercial buildings than techniques for reducing heat transfer by conduction. However, as higher performance facades are developed, gas ?lls may become more common in commercial building windows as well. Multiple Panes and Suspended Plastic Films By adding a second pane, the insulating value of the window glass alone is doubled (the U-factor is reduced by half). As expected, adding a third or fourth pane of glass further increases the insulating value of the window, but with diminishing e?ect. Triple- and quadruple-glazed windows became commercially available in the 1980s as a response to the desire for more energy-e?cient windows (Figure 3-10). As each additional pane of glass adds to the insulating value of the assembly, it also reduces the visible light transmission and the solar heat gain coe?cient. Additional panes of glass increase the weight and thickness of the unit, which makes mounting and handling more di?cult and

3. transportation more expensive. Prototype windows using very thin layers of glass (0.5-1.0 mm) have been fabricated but are not in commercial production. It is apparent that there are physical and economic limits to the number of glass panes that can be added to a window assembly. However, multiple-pane units are not limited to glass assemblies. One innovation is based on substituting an inner plastic ?lm for the middle layer of glass. The lightweight of plastic ?lm is advantageous, and because it is very thin, does not increase the unit thickness. As with triple- or quadruple-glazed windows, windows using plastic ?lms decrease the U-factor of the unit assembly by dividing the inner air space into multiple chambers. IGU Installations Double Glazed Melbourne can remove your existing glazing and install high performance double glazed units (IGU). The units are designed to suit the orientation of your home to maximise solar gain in winter and solar re?ection in summer. Giving you a great all-round high performance and comfort level in your home Suburbs we service… View larger map Map Data Terms of Use M av en W i ndow s serv i ces m ai nl y i n the i nner 2 0 k m radi us of the M el bourne CB D . Covering suburbs such as: Albert Park, Ascot vale, Brighton,

4. Carlton, Canterbury, Caul?eld, Clifton Hill, Collingwood East Melbourne, Fitzroy, Elwood, Glen Iris, Hawthorn, Malvern, Middle Park, North Melbourne Port Melbourne Richmond South Melbourne South Yarra, St Kilda, Toorak, Windsor. …just ask if your suburb is not covered. Useful Links Insulated Glazing Units Low-E Coatings Laminated Glass Terms & Warranty Information   Call us: 1300 812 201 Email: darren@mavendoubleglazing.com.au

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