Any Australian who has been to Europe may have noticed that in cities such as Berlin or Tallinn, double glazed windows are a standard feature of building design. Of course this can be partly explained by colder European winters, but for those of us living in the chillier southern parts of Australia this seems like a missed opportunity.
In Australia, most homes are built with single glazed windows creating a thermal weak spot – up to 87% of heat is increased through thin windows in summer and 40% lost in winter. About 40% of Australian household energy use is for heating and cooling, so double glazing can significantly bring down energy bills while reducing noise levels.
The purpose of double glazing is to create an insulating layer of gas trapped between two (or more) layers of thick glass (known as insulating glass units or IGU’s), thereby increasing sound and comfort levels while reducing energy demand inside your home.
But like many things, double glazing doesn’t come cheap. Navigating the myriad of options on the market can be overwhelming. Here is where to start.
Consider the different options
Living in a century-old art deco apartment in Melbourne’s bayside, my partner and I found ourselves shivering through chilly Melbourne winters and paying increasingly high power bills to warm the apartment using electric heaters.
So we started researching the options out there for double glazing and soon realised it was way more complicated than we’d thought. The first thing to recommend is get at least three quotes. The prices will vary significantly according to the type of double glazing you choose.
“Consumers often think that all double glazing is the same, however this is not the case,” says Clinton Skeoch, the executive director and chief executive of the Australian Glass and Window Association.
“For those in climates that tend to be hotter, you may want to have more solar control or tint to help keep the heat out. If you are in a climate where it tends to be cooler, you will likely be looking for admitting in as much solar radiation as possible and keeping it in your house by changing what surface the glass coatings are on.”
Factor in other costs
The quotes we received for five windows varied between $5,000 for detachable double-glazed window add-ons that are attached with magnets to the existing windows to $20,000 for a complete window rebuild. We decided the cheaper detachable option wouldn’t work for us as we don’t have space to store the windows when we want to let fresh air into the apartment, especially in summer time.
In the end we settled for a mid-price option that placed the new double-glazed windows inside the existing window frames and cost just over $10,000. But that’s when things became even more complicated. As our building has a heritage overlay, our body corporate informed us we’d need council approval to get double glazing done as it would affect the outside appearance of the building.
Our local council charged just over $300 for this approval (you need to provide them with all the work details from the double glazing company) but we managed to convince our building’s body corporate to cover this cost, so it’s certainly worth asking. Once that council approval came through the work commenced after a few months delay (double-glazing companies often have long waiting lists).
Work on making the rest of your house more efficient
Double glazing has been a great addition to our century-old apartment.
We immediately noticed significantly reduced street sounds coming in and we’re looking forward to a more livable temperature in winter. But it’s important to be aware that the windows are only part of the solution.
Tim Forcey, author of My Efficient Electric Home handbook, says double-glazing is a great addition but only part of improving a home’s overall efficiency.
“Don’t expect new windows to solve all your problems,” he says. “Double glazing can have multiple benefits including noise reduction, less moisture condensation inside in winter, they are more secure and generally thermally better.”
Clinton Skeoch agrees, noting that double glazed windows will perform better in a home that has wall and roof insulation in place.
“Ultimately by maximising the performance of a house’s thermal envelope homeowners are investing in a product that works to improve energy efficiency, reduce heating and cooling costs and comfort regardless of if the sun is shining.”
