A lot of Melbourne homes still have one sheet of glass in each window, often in an old aluminium frame. Those windows let heat out on a cold July night, let it in on a 40 degree afternoon, and let the street noise straight through. On winter mornings the glass fogs up and drips onto the sill.
Double glazed windows fix most of that. Whether they're worth it for your house depends on what bothers you most, how old your windows are, and your budget. Here's what to weigh up before you ask anyone for a quote.
Why Melbourne Homes Lose Heat Through Their Windows
Glass is a poor insulator. A single sheet sits between your warm room and the cold outside, so heat moves through it quickly. In summer it works the other way, and the sun heats the room through the glass.
The frame matters too. Older aluminium frames are solid metal from the outside face to the inside face. Metal carries heat and cold well, so the frame goes cold in winter and carries that cold into the room.
That's why a heater can run all evening and the room near the window still feels cool.
How Double Glazed Windows Work
A double glazed window has:
- Two panes of glass instead of one.
- A sealed gap between them. It's filled with air, or with argon, a gas heavier than air that slows heat down a little more.
- An edge seal that keeps the gap dry and closed. The two panes and the seal together are called an insulating glass unit.
Heat has to cross the first pane, the gap and the second pane. That takes longer than crossing one sheet of glass, so more of your heating stays in and more of the summer heat stays out.
The frame can be upgraded as well. A thermally broken aluminium frame has its inside and outside halves joined by an insulating strip, called a thermal break. The strip stops cold travelling through the metal into the room. Read how thermally broken windows work.
The Benefits You'll Notice In A Melbourne Home
- Warmer in winter. The inside pane stays closer to room temperature, so the room near the window doesn't feel as cold.
- Cooler in summer. Heat comes through more slowly. Low-E glass, which has a very thin coating that reflects heat, does more.
- Heater and air con working less. Less warmth escapes in winter and less heat gets in in summer. How much less depends on your house, so be wary of anyone promising an exact saving.
- Less street noise. Sound has two panes and a gap to get past instead of one sheet.
- Less foggy glass. Condensation forms when warm, damp air meets cold glass. The inside pane of a double glazed window stays warmer, so it fogs up less.
- A more comfortable room. You can sit near the window in July without a blanket.
Double Glazed Windows Vs Single Glazed Windows
| Single glazed | Double glazed | |
|---|---|---|
| Winter | The glass goes cold, and so does the room beside it | The sealed gap keeps the cold on the outside pane |
| Summer | Heat comes through the glass easily | Heat comes through more slowly |
| Street noise | One sheet is the easiest way in for noise | Two panes and a gap to get past |
| Condensation | Cold glass fogs up on winter mornings | The inside pane stays warmer and fogs up less |
| Upfront cost | Costs less | Costs more |
Single glazing only wins on price. On comfort, noise and condensation, double glazing comes out ahead.
Retrofit Double Glazing Vs Full Window Replacement
"Retrofit" means adding double glazing to a house that's already built. It covers two different jobs, so check which one a supplier means before you compare quotes.
New glass in your existing frames. The frames stay, and the single sheet of glass is swapped for a double glazed unit. This can suit frames that are in good condition and deep enough to hold the thicker glass. The frame itself stays the same, so an old aluminium frame will still carry cold into the room.
A whole new window. The old window comes out, frame and glass together, and a new double glazed window goes into the same opening. This usually suits old, damaged, draughty or poorly performing frames, and it's the only way to get a thermally broken frame.
Neither is always better. It comes down to the state of your frames and what you want to fix. We do the second kind, whole new aluminium windows. Here's how retrofit double glazing in Melbourne works, and how whole-window replacement runs from start to finish.
How Much Do Double Glazed Windows Cost In Melbourne?
Prices vary a lot across Melbourne, so any quote comes down to your own house. The things that usually move the price are:
- The size of each window. A big sliding door costs more than a small bathroom window.
- How many windows and doors are being done.
- The frame. Aluminium, uPVC or timber, and whether an aluminium frame is thermally broken.
- The glass. Low-E, argon filled, laminated, acoustic or tinted.
- Access. Upstairs windows, tight side paths and apartments can take more work.
- Retrofit or full replacement.
With us, windows are priced on their size in square metres. Thermally broken windows are about $600 a square metre. Two jobs we've priced:
- A whole house of windows: 44 square metres of thermally broken windows came to roughly $20,000 to $25,000.
- Three sets of bifold doors, each about 3.6 m wide and 2.1 m high: we quoted $25,000. The homeowner's other quotes were $50,000 and $60,000.
The final price is confirmed on your quote after we measure. Our double glazing cost guide shows how to work out your own square metres.
The Best Rooms To Upgrade First
If you can't do the whole house at once, start where you'll feel it most:
- Bedrooms, for sleep, warmth and quiet.
- The living room, where you spend your evenings.
- Street-facing windows, where the traffic noise comes in.
- West-facing rooms, which take the hot afternoon sun.
- Any room with old aluminium windows, where the frame is carrying the cold in.
One room or one sliding door is a fine place to start. Plenty of people do a room first and the rest of the house later.
Is Double Glazing Worth It For Noise?
Yes, for most homes near a busy road. Double glazing reduces the noise coming through the glass because sound has two panes and a sealed gap to get past.
For a main road, a train line or a flight path, the glass matters more. Acoustic glass is laminated glass, two sheets bonded with a layer that damps sound, and it cuts down more noise than standard double glazing.
No window makes a room silent. Noise also gets in through gaps around old frames, vents and open windows, which is one more reason people replace the whole window. How much quieter a room gets depends on the glass, the window and the noise outside. Here's more on noise reduction windows in Melbourne.
What To Check Before Choosing A Supplier
- Which retrofit they mean. New glass in old frames, or whole new windows.
- The frame material. Aluminium, uPVC and timber all do the job. They differ in look, upkeep and price. We supply aluminium only.
- Whether the frame is thermally broken, if you're choosing aluminium.
- The glass in the quote. Low-E, argon, laminated or acoustic.
- The Australian Standards. Ask what the windows are supplied to. For windows it's AS 2047, and for glass it's AS 1288.
- Who measures and who installs. Your own measure, and the business's own install team, means fewer gaps between who quoted and who fitted.
- The warranty, in writing, for the product and the installation.
- A clear quote that shows the square metres, so you can compare quotes by the price per square metre.
The Verdict
Double glazing is worth considering for most Melbourne homes. It pays off most where you feel the cold near the windows, the summer sun heats the house, the street is noisy or the glass fogs up every winter morning.
It costs more than single glazing, and the right choice between new glass and new windows depends on your frames. Get a quote on your own house before you decide.
Get A Quote For Your House
Send us how many windows and doors you have, your suburb and a few photos. We'll come back with a ballpark, then measure every window ourselves before anything is ordered. See our double glazed windows for Melbourne homes.
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