Advances in glass technology have contributed greatly to energy efficiency as well as comfort levels. Temperatures vary considerably between day and night, and from season to season. The greater the temperature difference between inside and outside, the greater the heat flow. Heat travels relatively easily through ordinary glass. In winter from inside to outside, and in summer from outside towards cooler air inside. This process can be slowed with insulation.
The incorporation of Insulated Glass Units (double glazing) into windows and glazing is an established approach to improving the thermal insulation performance. Double glazing can be considered for both cooler climates as well as warm environments to provide improved comfort and more efficient use of energy.
Insulated Glass Units provide an opportunity to tailor performance to needs, or to comply with specific project requirements. Insulated Glass Units can be manufactured with multiple choice of glass using clear, toned, high performance, laminated or toughened glass and with spacer bars of varying widths.
Warmer in Winter
Windows play a significant role in the energy required for heating and cooling. In a typically well insulated building with standard clear single glazing, up to 49% of heat is lost in winter through the windows. The use of Insulated Glass Units allows greater control of how much heat escapes through the windows in winter. By cutting the temperature transfer from warm (inside) to cold (outside), Chevron Insulated Glass Units can significantly reduce the loss of warmth in cold weather.
Cooler in Summer
Heat gain through the glass depends on many factors such as any shading, the elevation, glass type, thickness and temperature. In a typically well insulated building with standard clear single glazing, windows allow the transfer of up to 84% of solar heat gain in summer. By reducing the temperature transfer from hot air (outside) to cooler air (inside), Insulated Glass Units can create a noticeably cooler environment in summer.
Properly selected and installed, Chevron Insulated Glass Units can reduce noise by up to 65% compared to ordinary glass. Chevron Insulated Glass Units can be designed to reduce unwanted noise. Noise can vary, so the selection of an appropriate Insulated Glass Unit may vary to improve the noise reduction. For example:
- maximizing the width of the air space
- using glass of different thicknesses
- Incorporating laminated glass in one or both panes
It is important to note that no matter how effective the noise reduction of the Insulated Glass Unit, entry points for noise such as gaps in and around the window frame, walls, ceilings, vents, loose fitting doors and floors also need to be properly sealed.
Insulated Glass Units must be properly installed in accordance with AS/NZS 4666, (see below). It is essential to seek advice from the material suppliers/ manufacturers that the type of glazing compound, sealant or gaskets is compatible and suitable for the chosen glazing system. When Insulated Glass Units are specified for structural glazing (i.e. structural silicone as the secondary seal), it is the installer’s responsibility to ensure that the glass types and all other components to be used (such as setting blocks, backer rods, structural silicone and glazing compounds) are compatible with the structural silicone used to seal the Insulated Glass Units. It is essential that this is checked with the material suppliers/manufacturers for compatibility and suitability for each project.
AS/NZS 4666 – Insulated Glass Units This standard sets out the performance requirements and guidelines on the selection and installation of Insulated Glass Units.
Understanding terminology relating to thermal transmittance (U-Value) and solar heat gain coefficient (SHGC) are important in selecting glazing that will keep your home or office warm in winter and cool in summer.
Solar Heat Gain Coefficient (SHGC)
Low E Glass
Frames can be timber, aluminum, uPVC, or steel. It is essential to ensure the edges of Insulated Glass Units do not come into contact with or be allowed to remain in contact with water, as this can cause premature seal failure and/or delamination. Chevron Glass requires impervious weather seals and/or an adequate weep or drain system to prevent this from occurring.