Most windows in Australia have a single pane of glass, but double glazing—or even triple glazing—can have significant energy saving benefits for reducing winter heat loss and summer heat gain.
This is because they trap air between the panes acting as insulation and helping to make the temperature of the inside of the window as close as possible to the desired room temperature.
Glass balcony or patio doors, especially sliding glass doors, can be much less energy efficient than other kinds of doors as glass is a poor insulator. If you're thinking of buying new glass doors, ensure they have appropriate insulation and glazing.
An energy efficient door may cost more upfront, but you're likely to save money from your heating and cooling costs in the long run.
If you have existing glass doors, consider investing in some window furnishings to prevent heat loss in winter and heat gain in summer.
External windows and doors are generally common property (check your strata plan to make sure). You’ll need a resolution of the owners corporation at a general meeting. The owners corporation will also require a by-law to ensure you’re responsible for ongoing maintenance.
The decision of whether to retrofit double or triple glazing will depend on your heating and cooling needs against the costs.
There’s comprehensive information on glazing at the Australian Government’s Your Home website.
The Australian Window Association website has window climate zone guides for more information on what kind of window is most energy efficient for your climate.
The Window Energy Rating Scheme (WERS) rates the energy-related performance of windows, skylights and glazed doors—the more stars the better.
Window insulation film is a much cheaper DIY alternative if you can’t afford double glazing or you’re renting.
Bubble wrap will also do the job - instructions for bubble wrap glazing.