What your windows are made of may not exactly be your favourite dinner party conversation, but here are a couple of stats to prick your ears up!
According to a study, in winter, windows are responsible for up to 49% of the heat lost from your house and up to 87% of the heat gained by your house in summer. Yikes!
With Australia having some of the highest energy costs in the world, plus the obvious impact of cooling and heating on the environment, getting the most energy-efficient glazing is worth considering.
At Ecovue, we are passionate about double-glazing. Here’s our guide to how double-glazed windows stack up compared to other window types, so you can make the right choice for your home.
What is Double Glazing?
Double glazing refers to windows that are constructed from two panes of glass.
The key feature is that the glass panes do not touch each other. Instead, there’s a gap filled with either air or a vacuum, which acts as an insulator. This is where the major benefits of double-glazing come from.
They come in a variety of styles and whether you're looking for double-hung windows or casement windows, you install double glazing. It can help solve a number of issues associated with other types of windows. Speaking of which, let’s check out the other options on the market.
Checking Out the Competition
Double-glazed windows are common in Europe but have been less quick to catch on in Australia. Some of that could come from a 1970s oil crisis, which led to a drive for greater energy efficiency in those countries. Double glazing fit the bill.
Whatever the reason, many Australians still plum for more traditional window types. Here are some examples:
Single Glazing
Single glazing does exactly what it says on the tin – one sheet of glass per window.
This is probably what most of us grew up with, and we often find it in traditional sash windows. It looks good, and you can see through it – but that’s about the sum total of its benefits.
Triple Glazing
At the other extreme, we have triple glazing. This is similar to double glazing but has three layers, along with two layers of insulation.
As you’d expect, this produces pretty awesome energy efficiency. However, that has to be offset against the cost and practicality of them – more on that later.
How Do They Compare?
These days, we ask far more of our windows than simply keeping the draft and rain out.
Three important markers of good windows are energy efficiency, durability, and cost.
Let’s put the three types through their paces and see how they stack up.
Energy Efficiency
The science of heat transfer is at the heart of energy efficiency.
Homes lose heat in the winter as the cold air outside is attracted to the warm air inside, entering through the windows.
In summer, the cool inside air is attracted to the warm outside air – leading to a loss of cooling. The energy efficiency of a window gets measured in something called a U-value. Look for options with a lower U-value, which means that it insulates more efficiently.
Single-glazed windows do little to stand in the way of this unwanted and costly heat exchange. In fact, they positively support it.
On the other hand, triple glazing is even more energy efficient than double glazing. So what’s the snag? The insulation benefits have to be weighed against its incredible weight – requiring stronger frames – and the resulting higher cost.
Durability
Double glazing is usually supplied in uPVC frames.
They’re made in a variety of styles and colours and don’t need to be painted. That’s a major advantage, as it means that they are better suited to Australia’s varied climate.
Whether you’re by the beach in Sydney, coping with high levels of heat, or getting lashed by rain and cold in Tasmania, uPVC frames will stand up to whatever nature throws at them.
Triple glazing is also very durable. However, the weight of the panes often requires stronger fibreglass frames. While these look great, it adds a lot to the cost.
Single-glazed windows have traditionally been supplied in wooden frames or aluminium frames in recent years. Unlike uPVC frames, which are easy to seal and give a lot of protection from the elements, wooden frames require constant attention.
Think of the thousands of dollars you’d have to spend in the lifetime of a set of single-glazed windows on repainting and repairing damaged frames.
When they've been correctly installed, you should expect a lifespan of 20 years or more from your double-glazed windows.
Cost
When considering the cost of installing new windows, two factors need to be kept in mind.
Firstly, the cost of installation. Many people forget to look beyond this headline cost to the second – the money the windows will either save you or cost you on ongoing maintenance and on your energy bills.
As mentioned earlier, triple glazing is very energy efficient. However, more glass means more weight, needing stronger – and more expensive – frames. Currently, this outlay is prohibitive for most households.
Single glazing is usually in aluminium or sometimes wooden frames, which are more expensive. Aluminium framed single-glazed windows usually cost less upfront. However, as they are less energy efficient, you will pay more for your energy bills in the long run.
Double glazing with uPVC frames does cost a little more initially. However, once installed, it can dramatically improve the energy efficiency of your home. This means that you’ll make savings year on year and have less of an impact on the environment.
The Takeaway: Why Double-Glazed Windows Win
You’ve looked at all the evidence, and what’s the verdict?
Yes, there’s a clear winner. On energy efficiency, durability and cost, double-glazed windows are the way to go.
Single glazing has had its day. There’s no reason to allow heat to flood in or cool to pour out because of poor quality glazing anymore.
And while triple glazing is pretty awesome, until the cost comes down, this will continue to mean that it is not the most practical option for most households looking to replace their windows.
At Ecovue, we have an awesome range of double-glazing options for your home, so get in touch for a free quote today!
