Energy Efficient Windows in Canberra

Windows have traditionally been treated as just any another building material.  They are sourced as cheaply as possible and the same traditional style is put into the design and the build.  What a lot of builders, architects and home owners don't take into account is that they provide a massive opportunity to improve the insulation of the home.  

They provide light into the home along with fresh air but they also provide the opportunity to save heat loss in winter and heat gain in summer.  The frames play just an important part of the insulation process as the glass.  These are the best frame materials for energy efficient homes:

1. uPVC frames
2. Timber frames
3. Thermally broken aluminium frames

Combine the insulated frames with double glazed units and you will experience comfort, cheaper energy bills and still have light coming into your home.

Australia has a wide range of Climate Classes.  Canberra is a heating climate and is in Zone 7.  In Canberra we want to draw the sun into our home and then trap it there to benefit from free solar heating.  In summer we want to keep the heat out but be able to open our windows to benefit from the air flow.

In Canberra we want our windows to have a low U-value and high solar heat gain coefficient (SHGC) (see below).  It is important to ensure that each window and elevation (N,S,E and W) are considered to ensure they let the sun in during winter and keep the sun out during summer.  www.wers.net show the ratings of all rated windows and you should consider these when selecting your windows and doors.  Solace Creations provides a wonderful advisory service on new plans and existing homes to help you to select the best windows for your home www.solacecreations.com.au.

When you are building a new home or extending an existing home, ACT Government requires that a glazing calculator is completed or an energy audit to make sure that the required star rating is achieved.  The U-value and SHGC are important factors for the calculations and can be found on www.wers.net or from your window supplier.

What is a U-value

Wall insulation such as batts have an R-value rating.  This best batts for insulation is as high a rating as possible.  Windows and doors have U-values and for Canberra you want a low rating.  The U-value is a measurement on how well the windows and doors prevent heat from escaping.  Ratings can be from 2.0 to 10.  This should include the frame, glass, seals and spacers.  If a window such as ours has a U-value of 1.8, that means that 1.8 watts per metre is lost per hour.  Some aluminium windows are rated at 5.8. This shows that those windows lose heat much quicker than those with a lower U-value.  You can double glaze standard aluminium but the frame will still leak a lot of your heat.

What is Solar Heat Gain Co-efficent (SHGC)?

SHGC is a measure on how well the windows and doors block heat caused by sunlight.  This measure is a combination of how much sun is directly transmitted towards the window, absorbed by the window and ultimately released inwardly.  The SHGC is a number between 0 and 1.  The lower the number, the less heat it transmits.  The low ratings are excellent for the west side, however, you need to remember that if you have a low SHGC in summer, it will also be a low SHGC in winter meaning that you won't get as much of that lovely afternoon sun through your windows and doors in winter.  You can't beat natural shading from a tree or an awning for the summer westerly sun.

Orientation

Nothing beats perfect orientation and more aspects of energy efficient homes will be discussed in further blogs.  If you orient your home correctly, seal up the whole building envelope with insulation (including windows and doors) then you will not have to rely on heating or airconditioning.  This will save you $$$ on your bills and you are contributing to our planet.

Picture source:  www.wers.net

17 Townsville Street Fyshwick www.solacecreations.com.au