What Affects the Cost of Double Glazed Windows?

Double glazed windows cost different amounts from one home to the next because every price is built from the same handful of factors: window size and number, opening style, frame material, glass package, installation complexity and compliance needs. At RJV Industries, we supply and install uPVC double glazed windows across Nowra, the Shoalhaven, Wollongong and the Illawarra, and in this guide we explain what drives the cost of double glazed windows so you can make sense of a quote before you get one.

Key Takeaways

• There is no single per-window or per-square-metre price for double glazing. The cost depends on size, style, frame material, glass, installation and compliance.
• Online averages rarely match real quotes because they ignore site access, removal of old windows, bushfire (BAL) requirements and finishing work.
• Our uPVC double glazed windows are WERS rated, designed and manufactured in the USA, and available supply-only or supply and install.
• Matching the glass package to each room, instead of upgrading everything to the top specification, is one of the simplest ways to control cost.
• The only reliable figure comes from a free, no-obligation measure and quote. Call RJV Industries on 0457 431 660.

How Double Glazing Is Priced (and Why There's No One-Size-Fits-All Cost)

Double glazing is priced per opening, with each window or glazed door quoted on its own size, frame, glass, hardware and labour. That's why two homes with the same number of windows can get very different totals, and why a figure you read online for Melbourne or Perth tells you little about a home in Bomaderry or Figtree.

National "average" price tables are a common source of confusion for South Coast homeowners. They usually leave out the parts of a job that move the price the most: removing existing windows, making good around new frames, meeting bushfire or safety glazing rules and getting materials onto a tricky site. We'd rather you understand what goes into the number than anchor to a figure that was never about your house.

At RJV Industries we prepare an itemised quote after a site measure, so every opening reflects what it actually needs. If you're budgeting early, think in terms of total glazed area and how complex each opening is, then let a measure and quote turn that into a real figure.

Window Size, Quantity and Configuration

The total area of glass and the number of openings are the first things that shape the cost of installing double glazed windows. Bigger windows need more glass, more frame and heavier hardware, and very large panes may need thicker glass or reinforced frames to meet structural and safety standards.

Small windows aren't always cheaper per square metre, though. Every opening carries its own seals, hardware, frame sections and installation time, so a row of small windows can cost more per square metre than one larger panel.

The opening style matters as much as the size:

• Fixed windows are the simplest: no moving parts, fewer seals and minimal hardware.
• Awning and casement windows add hinges, stays, locks and weather seals.
• Sliding and double hung windows need tracks, rollers and balanced sashes.
• Sliding and bi-fold doors carry the most glass and hardware, and usually the most installation work.

A small fixed bathroom window and a large sliding door onto a deck in Berry sit at opposite ends of the scale, even with the same frame and glass. Style is one of the main reasons two quotes can look so different.

Frame Material: Why uPVC Often Delivers the Best Value

Frame material affects both what you pay upfront and what you spend looking after your windows over time. Across NSW, the three common choices are uPVC, aluminium and timber.

• uPVC frames are rigid and naturally insulating, they never need repainting, and they won't rust or rot in salt air. Our uPVC frames are WERS rated and designed and manufactured in the USA.
• Aluminium frames conduct heat and cold readily, which works against the insulated glass they hold. Thermally broken aluminium closes some of that gap, but the extra manufacturing lifts the price.
• Timber frames have a traditional look but need regular painting or staining and can swell or rot in coastal moisture, which adds ongoing cost in Shoalhaven and Illawarra conditions.

If you're weighing up frames in more detail, our guide to why uPVC windows and doors are a durable, low-maintenance choice covers the long-term side. For most South Coast homes, uPVC gives the best balance of upfront cost, thermal performance and low upkeep.

Glass Type and Performance Options

The glass inside each double glazed unit is one of the biggest variables in both performance and price. Clear double glazing, Low-E coatings, gas fills, laminated and toughened glass all cost different amounts and do different jobs.

• Clear double glazing: two panes with a sealed gap. A solid step up from single glazing.
• Low-E glass: a microscopically thin coating that reflects heat, helping keep warmth in during winter and limit heat gain on west-facing windows.
• Argon gas fill: a denser gas than air between the panes, which slows heat transfer.
• Laminated glass: holds together if broken and helps with security and sound.
• Toughened glass: required in certain positions, such as doors, low windows and wet areas.

Our standard Premium glass package pairs one Low-E pane with one clear pane and an argon fill. We also offer triple pane Advanced and Advanced Max packages; you can compare all three on our glass options page. Not every room needs the top specification. Matching glass to each room's use, orientation and noise exposure is a smart way to manage the overall cost. For more on why the glass matters, see how double glazed windows are more energy efficient.

Installation Complexity and Site Access

Installation is where a window's thermal and acoustic performance is either locked in or lost, and it's also where costs vary most from job to job. Proper sealing, alignment and weatherproof flashing are non-negotiable, and the effort to get there depends on your home.

• Single-storey homes with clear access are the most straightforward.
• Second-storey windows may need scaffolding or lifting equipment.
• Steep, narrow or hard-to-reach blocks, common in older parts of Wollongong and around Kiama, add time and logistics.
• Replacing windows in a lived-in home means protecting interiors, managing dust and carefully removing old frames.

RJV Industries offers supply-only for builders and experienced renovators, and full supply and installation for homeowners. We don't recommend DIY installation, because poor sealing can lead to leaks and undo the performance you've paid for.

Working With Existing Windows: Retrofit vs Replacement vs Secondary Glazing

Many South Coast homes already have aluminium or timber windows, and how you deal with them has a big influence on cost. There are three broad approaches.

• Retrofitting puts new double glazed units into existing frames. It only works when the frames are sound, square and deep enough for a thicker sealed unit, and adapting old frames can add labour.
• Secondary glazing adds a separate inner pane behind existing single glazing. It keeps the outside appearance unchanged, which can matter for heritage or strata homes, but it doesn't perform like a factory-sealed unit in a new frame.
• Full replacement with new uPVC double glazed windows gives the cleanest result: a complete, rated window system with new seals and hardware.

During our free measure and quote, we check the condition of your existing windows and tell you which approach makes the most sense for each opening.

Compliance, BAL Ratings and Local Climate Considerations

Building rules and local conditions can add requirements that change the cost of double glazed windows. Australian Standards set requirements for window performance and safety glazing positions, and compliant products and installation matter for safety, insurance and resale.

In bushfire-prone parts of the Shoalhaven and Illawarra, including semi-rural areas like Nowra Hill and Worrigee, windows may need to meet a specific Bushfire Attack Level (BAL). A BAL rating can dictate frame, glass and screening requirements, which changes the specification and the price. We supply BAL-rated windows manufactured to meet relevant Bushfire Attack Level requirements, so let us know your property's BAL rating when you enquire.

Coastal exposure matters too. Salt air, strong sun and wind call for corrosion-resistant hardware and UV-stable materials, which is one reason uPVC frames are popular along the South Coast. Our windows are WERS rated, and we supply products to suit BASIX and NCC requirements.

Project Scope: Whole-Home Upgrades vs Targeted Replacements

How much of the house you upgrade at once has a direct effect on the total. Doing several openings in one visit shares the site setup, travel and access planning, which is usually more efficient than lots of small jobs.

If a whole-home upgrade isn't in the budget yet, start with the rooms that will make the biggest difference:

• Street-facing bedrooms where traffic noise is a problem
• West-facing living areas that cop the afternoon sun
• Rooms with old windows that leak, rattle, stick or fog up with condensation

We're happy to help you plan a staged upgrade that fits your budget and renovation timeline. If you're still deciding whether the upgrade is worth it at all, our article on double glazed windows as an investment walks through the long-term benefits.

How RJV Industries Puts Your Double Glazing Quote Together

RJV Industries is a locally owned window business based at 20 Berry Street, Nowra, with more than 10 years' experience supplying and installing windows across the Shoalhaven, Illawarra and South Coast. Here's how we put a quote together:

1. Initial chat: what you need, which rooms matter most and your rough timeline.
2. Free on-site measure: we measure each opening, inspect the existing frames and check access.
3. Frame and glass selection: we talk through window styles, glass packages and hardware against your comfort, noise and energy goals.
4. Itemised quote: each opening is listed with its style, glass package and installation allowances, so you can see where the cost comes from.

You can choose supply-only or full supply and install. To see the windows themselves, visit our double glazed windows Nowra page.

How to Prepare for Your Double Glazing Project

A little preparation keeps your quote accurate and helps avoid changes once work starts. Before you book a measure, it helps to know:

• How many windows and doors you'd like to upgrade, and their rough sizes
• Which rooms are the priority for noise, heat, cold or security
• Any problems with existing windows, such as leaks, rot, condensation or sticking sashes
• Whether your property has an assigned BAL rating
• Any heritage, strata or estate rules about how the outside of the home can look
• Whether future renovations might change any window openings

Write down your questions about glass, frames, ventilation and how the quote splits between supply and installation, and we'll work through them during the site visit. Our guide on how to choose the right windows for your home is a good starting point.

Frequently Asked Questions About Double Glazed Windows Cost

Can I get a rough cost per square metre for double glazing?

A per-square-metre figure is only a rough budgeting tool, because frame, glass, opening style and installation can make two windows of the same size cost very different amounts. For a figure you can rely on, book a free, no-obligation measure and quote with RJV Industries.

Is it cheaper to retrofit double glazed units into my existing windows?

Retrofitting can save on materials when your existing frames are in good condition and deep enough to take a sealed unit. The extra labour to adapt old frames can eat into those savings, so we assess each opening on site and recommend retrofit, secondary glazing or replacement case by case.

Does secondary glazing always cost less than full replacement?

Not always. Secondary glazing avoids changing the outside of the home, but it still needs careful fitting to perform. Whether it works out cheaper depends on the number of openings, access and preparation, and its performance won't match a new frame with a factory-sealed unit.

How much does professional installation add to the overall cost?

Installation covers removing old windows, fitting, sealing, trimming and checking operation, and it varies most with storeys, access and the condition of the existing openings. Our quotes show supply and installation separately, so you can see exactly what the labour covers.

How do I get a tailored quote from RJV Industries?

Give RJV Industries a call on 0457 431 660 or get in touch through our website to book a free, no-obligation measure and quote. We'll measure each opening, check your existing windows and talk you through frame, glass and access options for your home in Nowra, Wollongong or anywhere across the Shoalhaven and Illawarra.