DOUBLE GLAZING (IGUs) FOR THERMAL CONTROL
IGU glass products are manufactured with two or more individual panes of glass first separated by a specified spacer bar system, this space is filled with gas or air and then sealed to be air and watertight. The airspace between the panes of glass forms an insulating barrier, which minimises the need for artificial climate control.
The majority of modern energy efficient window systems currently being implemented in the Australian building industry utilise some type of insulated glass (IG) application.
The effectiveness of insulating glass as an energy saver depends on the features that are incorporated into it. When purchasing insulating glass, clients need to consider the type of glass being used to make up the IGUs; the type of spacing material that holds the panes apart; the thickness of the space between the panes of glass; and the type of gas used in the air gap.
Type of Glass
- Clear or Solar Control GlassTinted glass and solar control coated glass can be used to increase the performance of the IGUs by reducing solar heat gain on a building facade and therefore reducing the energy cost of the building. Some of these coatings also decrease the passage of ultraviolet light (UV) into your home, which is notorious for causing fading in furniture and carpets.
- Low-E GlassLow-E glass reflects thermal radiation or inhibits its emission reducing heat transfer through the glass. Further solar radiation control can be added through the use of tinted glass and/ or solar control coated glass.
Type of Spacing Material
The glass panes for double glazed units are separated by a spacer -historically, spacers were made primarily of aluminium spacer bars. However, in this case the ability of the double glazed units to reduce heat flow is reduced because aluminium is a very conductive material. To reduce heat transfer through the spacer and increase overall thermal performance, the spacer may be constructed of a less-conductive material such as structural foam.
Warm Edge Spacer bar (Structural Foam, no-metal spacer system)
Benefits of Warm Edge Spacer bar:
- Thermal PerformanceWindows lose and gain heat by conduction, convention, radiation and air leakage. Unlike metal-based spacers, the all-foam construction of a warm edge spacer bar such as Super Spacer R is non-conductive thus blocks heat flow through the window. By blocking the heat escape path, Super Spacer provides one of the best thermal performances in the building industry.
- DurabilityUnlike metal spacers, warm edge spacer bars can bounce back when put to the test against winds, temperature fluctuation, rain, snow and UV light. The foam construction of the spacer allows it to expand and contract as needed, but always returning to its original shape.
- Mould PreventionThe fact that the warm edge spacer bar is nonconductive means that it also protects a major household threat: mould. Mould needs moisture to grow. Because of its non-conductive properties, a warm edge spacer bar can prevent condensation in the glass.
- Sound AbsorptionThe closed-cell polymer foam transmits very little sound compared to conventional metal spacers. The use of a warm edge spacer bar as opposed to aluminium spacer bar can reduce noise by up to 2dB and heat by 15%.
Super Spacer® TriSeal™ – For architectural and captured glazing IG units
Super Spacer TriSeal offers optimal performance and durability for light to heavy residential and the toughest in commercial glazing applications. TriSeal’s triple-seal design provides superior argon gas retention, low moisture-vapour transmission and optimal structural strength.
Thickness of The Space
The space between the two glass panes plays an integral role in determining the level of heat transfer. The maximum insulating efficiency of a standard IGU is determined by the thickness of this space as it contains gas or air – too little space between the panes of glass results in conductive heat loss between the panes (the inside surface of one pane cools the surface of the other pane) while too wide a gap results in convection current losses (gas begins to circulate because of temperature differences and transfers heat between the panes). Typically, most sealed units achieve maximum insulating values using a gas space of between 12-16 mm.
Type of Gas
In order to increase the insulating performance of IGUs, Argon gas is often used in the space between the panes. Argon gas has qualities that decrease the movement of heat through the space, thus improving efficiency. Higher viscosity reduces convective heat transfer. Argon has a thermal conductivity 67% that of air and is used because of its non-toxic, clear, odourless, chemically inert properties and commercially availability.
ORIGIN OZ is setting the industry standard for double glazed window systems in Australia. Our high performance IGUs are separated by Super Spacer TriSeal™ and filled with non-conductive Argon gas to give the best insulating properties. The space between the glasses significantly reduces any wave transmittance (heat, cold and sound) from the other side of the unit, making it an energy-saving and cost efficient material. Our insulated glass units are then sealed with silicon to comply with structural applications. We also offer a variety of high-performance fenestration products designed to help you improve overall efficiencies and product quality.