Double glazed windows in South Africa are no longer a special order. In our shop you can double glaze a top hung, side hung or fixed aluminium window online, see the price change as you choose it, and pay for it there and then. This guide shows real prices by size, explains how the price is worked out, and helps you decide where double glazed windows are worth it in your home.
If noise is the main reason for double glazing, read soundproof windows.
Buying in Johannesburg? See aluminium windows Johannesburg and aluminium doors Johannesburg.
All prices are for standard sizes, excluding VAT, and the same in every colour. You can browse every size in our aluminium windows shop or start with top hung aluminium windows, the window most people double glaze. For the reasons to double glaze at all, read the benefits of double glazing.
In this guide
What is a double glazed window?
A double glazed window has two panes of glass sealed together with a gap between them, instead of one pane. Our double-glazed unit is 24.76 mm thick: a pane of 6.38 mm laminated safety glass, a 12 mm cavity, and a second pane of 6.38 mm laminated safety glass. Both panes are safety glass, so you lose none of the protection of our standard glazing.
The sealed cavity is what does the work. Still air carries heat and sound far less readily than glass, so a double glazed window keeps more warmth inside on a winter night, lets less heat in through a sunny pane, and takes the edge off traffic and neighbourhood noise.
Double glazed windows South Africa prices by size
The table compares the same window single glazed in our 30.5 mm Standard frame, the double glazing price on top, and the total. The last column is the Casement 34 frame, a top hung window that always comes double glazed. Prices are regular prices excluding VAT, in any of our five colours.
| Window | Single glazed (30.5 mm) | Double glazing | Double glazed total | Casement 34 (double glazed) |
|---|---|---|---|---|
| Top hung 600 × 600 mm, single opener | R1 481 | +R748.24 | R2 229.24 | R1 564 |
| Top hung 900 × 900 mm, single opener | R2 439 | +R1 649.54 | R4 088.54 | R3 091 |
| Top hung 1 200 × 900 mm, single opener | R2 796 | +R2 222.05 | R5 018.05 | R4 672 |
| Top hung 1 200 × 1 200 mm, single opener | R3 475 | +R2 970.30 | R6 445.30 | R6 750 |
| Top hung 1 500 × 1 200 mm, twin opener | R4 243 | +R3 690.20 | R7 933.20 | R7 456 |
| Top hung 1 800 × 1 200 mm, twin opener | R4 978 | +R4 410.10 | R9 388.10 | R8 823 |
| Side hung 600 × 900 mm, single opener | R1 946 | +R1 111.03 | R3 057.03 | – |
| Side hung 1 200 × 1 200 mm, twin opener | R4 600 | +R2 992.97 | R7 592.97 | – |
| Fixed 1 200 × 1 200 mm, 1 pane | R1 858 | +R2 902.28 | R4 760.28 | – |
| Fixed 1 800 × 1 200 mm, 1 pane | R2 605 | +R4 330.75 | R6 935.75 | – |
Every size has its own page with the exact price, so if your window is not in this table, search the shop by width and height, for example 1500 x 900. Our cheaper Casement 28 frame is not made for the weight of double glazed windows, so double glazing is offered on the 30.5 mm Standard frame and the Casement 34 frame.
How the double glazing price is worked out
On a 30.5 mm Standard window, double glazing costs R1 952.50 per square metre of the window size, plus a small allowance for the deeper glazing bead that holds the thicker unit. On a 1 200 × 1 200 mm top hung window that is 1.44 m² × R1 952.50 = R2 811.60 for the glass, plus R158.70 for the bead, so R2 970.30 in total.
Three things set the final price of double glazed windows: the size of the window, because the unit is priced per square metre; the frame you choose; and the opening layout, because a twin opener has more glazing bead than a single opener. Colour makes no difference, and neither does the window style.
The rate is the same in every colour, and it replaces nothing: the window keeps all its hardware and simply takes the thicker glass. When you choose double glazing in the Glass list on a product page, the price on the page updates before you add it to the cart.
30.5 mm frame plus double glazing, or Casement 34?
Top hung windows give you two ways to get double glazed windows. You can take the 30.5 mm Standard frame and add double glazing, or choose the Casement 34 frame, which is built around the double-glazed unit from the start.
- Small and medium windows: Casement 34 is usually cheaper. A 1 200 × 900 mm single opener is R4 672 in Casement 34, against R5 018.05 for the 30.5 mm frame with double glazing.
- Larger windows: compare both. At 1 200 × 1 200 mm the 30.5 mm frame with double glazing is R6 445.30, slightly less than R6 750 for Casement 34.
- Side hung and fixed windows: these use the 30.5 mm Standard frame with double glazing.
Both options use the same 24.76 mm unit, so the double glazed windows perform the same. The difference is the frame profile around it.
Which windows can be double glazed online?
- Top hung windows in the 30.5 mm Standard frame or the Casement 34 frame.
- Side hung windows in the 30.5 mm Standard frame.
- Fixed windows in the 30.5 mm Standard frame.
Sliding and vertical sliding windows are supplied single glazed, as are louvre and clad designs. All our doors except the Patio sliding range can be double glazed too; see our guide to double glazed sliding doors for those prices.
Is double glazing worth it in South Africa?
Our climate is milder than Europe’s, so double glazed windows in South Africa earn their keep in particular rooms rather than everywhere. They pay off most where one of these is true:
- Cold Highveld winters. Bedrooms and living rooms in Johannesburg, Pretoria and the Free State lose a lot of heat through single glass on frosty nights.
- Noise. Bedrooms facing a busy road, a school or a neighbour’s entertainment area.
- Big glass facing the sun. North and west-facing living areas that get hot in summer afternoons. Here, also compare Solarshield laminated glass, which cuts glare and heat at a lower price.
- New builds. SANS 10400-XA, published by the SABS, sets energy rules for glazing in new homes, and better glass makes them easier to meet. Your architect or energy assessor will confirm what each plan needs.
Bathrooms, sculleries, garages and small windows on a quiet side of the house rarely need it. Many homeowners choose double glazed windows for the bedrooms and main living area and keep standard 6.38 mm laminated safety glass elsewhere. Our guide to window energy efficiency goes deeper into heat and sun.
Double glazed windows or performance glass?
Double glazed windows are not the only way to make a room more comfortable. Our single-pane glass options cost less and can be the better fit, depending on the problem you want to solve.
| Problem | Best choice | Why |
|---|---|---|
| Cold rooms in winter | Double glazed windows | The sealed cavity slows heat escaping through the glass at night. |
| Traffic or neighbour noise | Double glazed windows | Two laminated panes and an air gap cut more sound than one pane. |
| Hot afternoon sun and glare | Solarshield laminated glass | It reflects and absorbs more of the sun at a lower price than a double-glazed unit. |
| Privacy in a bathroom | Obscure laminated glass | It blurs the view while still letting light in. |
| A tight budget | Standard 6.38 mm laminated safety glass | It is included in every window price and is safety glass. |
If a room has more than one problem, such as a west-facing bedroom on a busy road, double glazed windows usually solve both. Every option is chosen in the same Glass list on the product page, so you can compare prices before you decide.
Living with double glazed windows
Double glazed windows need no special care. Clean the glass and frames as you would any window, with mild soapy water and a soft cloth, and keep the drainage slots at the bottom of the frame clear. Do not use a pressure washer on the seals.
Condensation on the room side of the glass on a cold morning is normal in a humid room; open the window to air it. Mist that appears between the two panes, inside the sealed unit, means the seal has failed and the unit should be replaced. Because each unit is made to the size of the opening, replacements are ordered to the same size.
Double glazed windows are heavier than single-glazed ones, so lift and carry them upright with two people, and let your installer know they are double glazed before the delivery day.
How to order double glazed windows
- Find the size of your double glazed windows in the shop, or price every window in the house in the online estimator.
- Choose the colour and frame, then pick double glazing in the Glass list, or choose the Casement 34 frame on a top hung window.
- Check the price, add it to the cart and pay online by card or instant EFT.
- We make it to order in 3 to 5 working days. Collect free from Laser Park or have it delivered; delivery is worked out at checkout by distance.
Our windows are supply only, so your own builder or installer fits them. A double-glazed unit is heavier than a single pane, so tell your installer the glass is double glazed when you book.
Double glazed windows South Africa: frequently asked questions
How much do double glazed windows cost in South Africa?
In our shop a 600 × 600 mm top hung window starts at R1 564 double glazed in the Casement 34 frame, and a 1 200 × 1 200 mm top hung window costs R6 445.30 in the 30.5 mm frame with double glazing, excluding VAT. Every standard size is priced online.
What is the double glazing price per square metre?
R1 952.50 per square metre of the window size, excluding VAT. On a 30.5 mm Standard window a small amount is added for the deeper glazing bead.
What glass is in your double glazed windows?
A 24.76 mm sealed unit: 6.38 mm laminated safety glass, a 12 mm cavity and a second pane of 6.38 mm laminated safety glass.
Can I double glaze a sliding window?
Not in our shop at the moment. Double glazing is offered on top hung, side hung and fixed windows, and on most of our doors.
Does double glazing cost more in Black or Bronze?
No. The double glazing rate and the window prices are the same in all five colours.
How long do double glazed windows take to make?
Like all our windows, double glazed windows are made to order in 3 to 5 working days once payment clears, then collected from Laser Park or delivered.
Do you install double glazed windows?
No. Our windows are supply only and are fitted by your own builder or installer. We deliver across South Africa or you can collect free from Laser Park, Johannesburg.
Coetz™, Unit 2, 84 Ridge Road, Laser Park, Johannesburg. Call 010 412 0062, WhatsApp 076 613 4418 or use our contact page.
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