While most energy assessors will quickly jump to the most obvious solution to improve the energy rating of your home, the energy assessors at Energy Rating Perth offer advice that includes several alternative solutions that can help achieve the same object at a lower cost.
Several glass types and window Treatments can help improve your energy rating. They are summarised below:
This consists of two (or three in case of triple) sheets of glass separated by an insulating layer such as air or an inert gas like argon. It is a very efficient system in reducing the U-value of a window but does not affect the SHGC much. This glazing system is preferable for climates when the external temperature is extreme for a long period of time or even in milder climates where a large amount of glazing is an aesthetic preference. While this may be the first preference of most energy assessor, installing double or triple-glazing is a costly exercise.
- Secondary glazing:
This is a retrofit system which converts an existing single glazing unit into a double glazed one by attaching another sheet of glass or acrylic to the window pane with a magnetic strip. This creates an air space, which reduces the U-value and the solar radiation transmission. This system can be used for older buildings to improve their thermal performance.
- Toned/Tinted glass:
This consists of a darkened glass that limits the amount of solar energy transmitted through it. It prevents unnecessary solar gain in a hot climate especially when external shading is not possible. Toned glass reduces the SHGC but has a nominal impact on the U-value. It can also inhibit the entry of visible light.
- Reflective glass:
This treatment is a thin metal film or a pyrolytic coating, which makes the surface of the glass reflective due to which unwanted incident solar radiation is reflected. Like toned glass, it is used in hot climates but can also reduce the VLT and cause glare which can be distracting for neighbours and motorists.
- Low-e Film:
Applying a low-e film reduces the emissivity of the glass, which means it will absorb and emit much less radiant heat. This can dramatically reduce both U-value as well as the SHGC. It is recommended for warmer climate where the aim is to reduce the amount of solar heat gain while maintaining a good level of visible light transmittance.
- Internal and External Shading systems:
Shading is an important component in the reduction of solar radiation transmission. While obvious shading solutions are eaves, pergolas and overhangs, shading can also be provided by internal vertical/venetian blinds and external roller shutters. This can significantly reduce unwanted solar radiation from penetrating the building. Although external shading is far more efficient than internal by reducing the solar heat gain by almost 75% it may not always be preferred aesthetically.
If you have completed the design for your home and it does not comply with the glazing requirements our energy efficiency assessors at Energy Rating Perth are experts in devising a way out to improve your energy rating and eventually achieve compliance with the NCC energy efficiency requirements. Contact us today for more info!