Work by JW Projects
Job photo by JW Projects

Price guide · Aluminium Doors and Windows

How Much Does Double Glazing Cost?

5.0 11 Google reviews

Quotes in Johannesburg, East Rand, Vaal Triangle, Durban and 7 more areas

  • Prices checked November 2026

Price guide

What it costs

Work by JW Projects
Aluminium Doors And Windows job by JW Projects

Double-glazing upgrade surcharge

From 2 businesses' published prices in Gauteng, checked November 2026.

More prices

  • Replacement aluminium window supplied and installed

    From Felix Glass & Aluminium's published prices in Gauteng, checked November 2026.

What these prices include: Double glazing is priced as an upgrade per square metre of window, on top of the window itself. Replacement window prices include taking out the old frame and fitting the new one.

What changes the price: The size, the opening type (fixed, side-hung, top-hung, sliding), standard or custom sizes, the frame colour, clear or obscure glass, and the fitting.

Recent work by these aluminium installers

Tell us the job and an aluminium installer that covers your area calls you with a written quote.

  • Work by JW Projects
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Job photos by JW Projects.

What you can ask for

  • Aluminium windowsNew or replacement aluminium windows, made to size.
  • Aluminium doorsHinged aluminium doors for patios, kitchens and entrances.
  • Sliding doorsAluminium sliding doors, supplied and fitted.
  • Stacking doorsAluminium doors that fold or stack open across a patio.
  • Other aluminium workShopfronts, louvres, balustrades and other aluminium work.

What is inside a double glazed unit

A double glazed unit is two or more panes held apart by a sealed spacer. The gap does the insulating, and also cuts noise and solar heat.

The gap
The cavity is usually 6 to 18mm wide, with 12mm the preferred gap; wider cavities insulate better.
Spacer and desiccant
A metal or polymer spacer holds the panes apart and contains a desiccant that dries out any moisture left in the cavity.
Argon
The cavity can be filled with an inert, low-conductivity gas such as argon instead of dry air.
Seal failure
A badly sealed unit with too little desiccant lets moisture in, which then condenses on the colder pane in cold weather.
Safety glass
The building regulations call for safety glass in places such as doors and sidelights up to 2100mm, windows with sills under 500mm, shower and bath glazing and balustrades, and that applies to a double glazed unit too.
Energy rules
SANS 10400-XA and SANS 204 set the energy rules for glazing; a home with up to 15% glazing to floor area per storey meets the minimum without more calculation.

Builders (South African building supply chain), how-to of building: glazing, blog.builders.co.za, checked 12 Nov 2026.

Aluminium installers near you

3 aluminium installers take requests here. Pick your area to see who covers it.

KwaZulu-Natal

Western Cape

  • Northern Suburbs

Who gives you the price

Your request goes to one that covers your area, not all three, so you get one call, not a string of them.

  • Work by JW Projects

    JW Projects

    Covers Centurion, East Rand and 3 more areas

    5.0 / 11 Google reviews

    On Local Pros since 2024

    • 6 years in business (since 2020)
    • Team of 4 to 6
    Yuanita A. says, “Very well priced!! Quick with quote and installation was done within a week!!!” Google

    In their words: JW Projects offers quality aluminium windows, doors, and related products in Pretoria, Centurion, Johannesburg, Vaal Triangle, and East Rand. With over 15 years of experience, we provide custom-sized solutions for residential and commercial clients.

    Profile and reviews ›

  • Home Pros team

    Home Pros

    Covers Durban and Durban North

    5.0 / 2 Local Pros reviews

    On Local Pros since 2024

    • 10 years in business (since 2016)
    • Team of 10 to 20
    • Owner managed
    Billa says, “I would absolutely recommend Homeprokzn , they always willing to go the extra mile and job well done” Local Pros

    In their words: Home Pros offers a wide range of services including awnings, balustrades, building construction, burglar bars, cladding, decking, driveway gates, drywall, flooring, gate motors, garage doors, fencing, general maintenance, carports, PVC fencing, shadeports, and aluminum products.

    Profile and reviews ›

  • Regency Aluminium And Glass logo

    Regency Aluminium And Glass

    Covers Atlantic Seaboard and CBD, Blouberg and surrounds and 2 more areas

    On Local Pros since 2024

    • 11 years in business (since 2015)
    • Team of 7 to 10
    • Gives a warranty

    In their words: Regency Aluminium And Glass offers aluminium products and services including balustrades, windows, doors, stack doors, sliding doors and more in Cape Town’s Northern Suburbs, Southern Suburbs, Atlantic Seaboard, CBD, Blouberg and surrounds.

What customers say about price and quotes

5.0

Average from 11 reviews of the 2 aluminium installers above on Google and Local Pros, checked November 2026.

  • Yuanita A.

    2 months ago

    Very well priced!! Quick with quote and installation was done within a week!!! Friendly team 👍

    Review of JW Projects left on Google

  • Kelly P.

    a year ago

    Great team, came out to quote, on time, received a quote the next day. Work was then carried out within 48hrs. I can definitely recommend Itumaleng and his team. Thanks guys, I can’t wait for the next phase.

    Review of JW Projects left on Google

  • Mahlatse M.

    a year ago

    I'm very happy with JW projects....Thy made our home very beautiful...I'll recommend everyone to consider their projects and their Pricing as very very reasonable....thank you very much JW projects ur the best 👌

    Review of JW Projects left on Google

More checked prices

Questions about these prices

Where do these prices come from?

From Felix Glass & Aluminium and Coetz Glazing: businesses that publish their own prices. We copied the figures as published and checked them on 13 November 2026. They are not quotes; every pro sets their own price.

How are these aluminium installers rated?

5.0 out of 5 on average, from 11 reviews of 2 aluminium installers.

Do I have to hire the pro who quotes?

No. You decide once you have the written quote.

The full guide

General advice, written April 2024.

Getting double-glazed windows can be among the very best ways to minimize heating and cooling expenses and do your part in saving energy. However, is it worth the additional cost?

This short article will assist you to find out about:

  • What is double glazing?
  • Why install double glazing?
  • Window designs and types
  • How much does double glazing cost?
  • Working with a window installer

Double glazing

What is double glazing?

A double-glazed window has 2 panes of glass separated by an air or gas pocket in between the panes (normally argon). This pocket is what makes a double-glazed window an efficient insulator, and it can also help reduce sound pollution entering your house. Technically, double-glazed windows are likewise called Insulated Glass Units (IGUs) due to the fact that the panes of glass should be effectively sealed into a single system to supply sufficient insulation. The space in between the panes can be anywhere between 6 mm and 20 mm, with a higher space providing better insulation. IGUs with argon gas filling the space are said to offer even better insulation.

Why install double glazing?

Numerous homeowners are having their windows changed or re-glazed to enhance energy efficiency and make their houses more comfortable. Double-glazed and/or low-e (low emissivity) windows can likewise decrease heat transfer substantially. While they cost more, they pay for themselves with time and continue conserving as much as 25% of your energy expenses. If your window frames remain in great condition, working with a window installer to install more energy-efficient glass can be more economical than changing your windows.

Depending on your individual energy consumption, it might take 5 years to recover the additional cost of double-glazed windows. Nevertheless, your one-time financial investment in windows will make your life more comfortable and help battle increasing energy expenses for many years. If you're remodelling, it makes good sense to pay extra for double-glazed windows in locations where you and your household spends a great deal of time. Aside from helping to reduce your energy usage, double glazing helps avoid cold and hot areas near windows and glass doors, providing you with greater convenience throughout the space.

Make the effort to compare the "R-values" and "U-values" of the double-glazed windows. This will tell you how energy-efficient the windows are. For even higher convenience and thermal performance, think about double glazing with Low-E glass panels.

What type of new windows?

What kind of brand-new windows?

If you are thinking about double glazing possibilities, you are most likely installing brand-new windows. This means you need to get your head around all the different window types and how they operate. The most typical are:

  • An awning is a window that opens externally and articulates and changes on a chain winder. Awning windows benefit challenging-to-reach areas in your house.
  • Bi-fold - these are concertina-like folding making them fantastic for optimum airflow.
  • Casement windows are some of the most typical window designs, select casement windows if you require optimal ventilation, as they open really wide.
  • Double-hung: with 2 different panels that go up and down separately, double-hung windows are low-profile windows that are fantastic if you need to fit flyscreens.
  • Fixed Pane: these windows are fixed sheets of glass in a frame and cannot be opened.
  • Louvres: these windows are comprised of a series of glass panels that can be manipulated to control airflow.
  • Sliding windows slide horizontally along a runner. They are really flexible windows and are fairly low-cost. Sliding windows match most house designs, use up little space, and are low upkeep. They are lockable for additional security.
What type of new windows?

How much do double glazed windows cost?

When you begin pricing double glazed windows, you'll discover the following will impact the cost:

  • The window design
  • What the frames are made of
  • The kind of glazing utilized
  • The size of your window

The price of a double-glazed window will depend upon its quality and insulation properties, but you can anticipate paying a minimum of 35%–50% more than for normal windows. The best prices for aluminium windows can be obtained at Aluminium Pros.

Composite window frames are typically less expensive than timber-framed windows.

How much does double glazing cost?

Hiring a glazier

When it comes time to employ a glazier, here are some questions to ask to ensure that you select the right contractor:

  • Are you a certified window installer?
  • Do you guarantee the work that you completed?
  • Can you offer a detailed quote?
  • Do you have any referrals I can follow up on?

Getting quotes for double-glazed windows

If you're in the market for glass or windows, get quotes from double-glazed window installers who service your area. They can help you pick the ideal window for your requirements and stick within your budget plan without compromising energy effectiveness or convenience.

How it works

  1. 1

    Tell us the job

  2. 2

    An aluminium installer who covers your area calls you

  3. 3

    Get a written quote and decide

Get quotes

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