Buying cheap aluminium windows looks like the easy way to save on a renovation, but the lowest quote often leaves out the things you only notice later: the glass, the frame, the finish and the paperwork. This guide explains where cheap windows and doors usually cut corners, what each shortcut ends up costing, and how to get a fair price without them.
For genuine bargains near Johannesburg, see cheap aluminium windows Gauteng.
See also our guide to second hand aluminium windows.
Our Casement 28 windows cost 15% less than the 30.5 mm Standard frame, in every colour; see the full list of aluminium windows and doors prices.
Prices and every standard size are on our aluminium windows page.
In this guide
Why buying cheap aluminium windows can cost more
Aluminium is a good material at almost any price – it does not rot, rust or need painting. The difference between a window that gives decades of service and one that gives trouble in five years is in the details around the aluminium. Buying cheap aluminium windows only works when you know which of those details a low quote has left out. Here are the seven places they usually go missing.
1. Float glass where safety glass belongs
The quickest way to cut the price of a window is thinner, cheaper glass, and many low quotes use 3 mm or 4 mm float glass. Float glass breaks into sharp pieces. SANS 10400-N, the glazing part of the national building standard published by the SABS, calls for safety glass in doors, low-level panes, bathrooms and other places where people can walk into glass. Every Coetz™ window and door comes with 6.38 mm clear laminated safety glass as standard, which holds together if it breaks. See safety glass vs float glass and where safety glass is required.
2. Light frames that flex
Thin, light aluminium sections save material but flex in the wind and under the weight of the glass. Over time the sash drops, catches on the frame and stops sealing. Coetz™ windows come in a 30.5 mm Standard frame, a 36 mm Heavy-Duty frame for bigger or more exposed openings and a 44 mm Commercial frame on selected fixed windows. Read more about aluminium window frames.
3. A finish that chalks and peels
A powder-coated finish is only as good as its pre-treatment and coating, and neither shows on the day you buy. A poor finish can chalk, fade or peel within a few years, and a frame is hard to recoat once it is built into the wall. Coetz™ powder-coated finishes carry a 5-year warranty, subject to normal cleaning.
4. Hardware that fails first
Handles, hinges, friction stays and rollers do all the moving, so they wear out first, and unbranded hardware is a common saving on the cheapest quotes. Our top hung and side hung windows come with wedgeless handles and stainless steel friction stays, and hardware is covered for 2 years against manufacturing defects.
5. Seals that let water in
Leaks are rarely the fault of the aluminium. They come from cheap seals, missing drainage and poor fitting, and fixing them means call-outs, sealant and sometimes damaged walls and floors. If your windows already leak, see aluminium windows leaking.
6. Odd sizes and a poor fit
A window made a few millimetres off size is packed and filled to fit, and that is where draughts and cracks start. Order standard sizes where you can, measure carefully and leave the right fitting gap – our guide on how to measure aluminium windows shows how.
7. No warranty and no paperwork
Buying cheap aluminium windows without paperwork leaves you nothing to claim against, because a verbal promise is worth little once the installer has moved on. Ask for the warranty in writing and, for new work, a glazing certificate from your installer. Coetz™ windows and doors carry a written warranty: 5 years on frames, glass and powder coating, and 2 years on hardware and seals. Read about the importance of a glazing certificate.
Cheap aluminium doors: where the risk is bigger
Doors take more weight, more use and more knocks than windows, so shortcuts show sooner. Cheap aluminium doors with poor rollers drag within a year, and a door panel in float glass is a real injury risk because people walk into doors. When you compare door prices, check the glass in every panel, the rollers and hook lock on sliding doors, and the frame that carries the glass. Our aluminium door buying guide covers each type.
How to get a fair price without cutting corners
Paying less does not have to mean buying worse. If you are buying cheap aluminium windows for a rental or a tight budget, these steps lower the cost without touching the quality:
- Use standard sizes – catalogue sizes cost less than one-off sizes.
- Compare like for like – the same glass, frame and finish on every quote.
- Choose 4 mm or 6 mm clear float glass only where safety glass is not required.
- Collect free from our Laser Park workshop instead of paying for delivery.
- Price every opening at once in the online estimator.
For more ways to save, see cheap aluminium windows: 6 ways to pay less. Every Coetz™ size is priced on its product page, excluding VAT, so you can compare before you buy – start with aluminium windows or aluminium doors.
Buying cheap aluminium windows: frequently asked questions
Are cheap aluminium windows worth it?
Sometimes. Buying cheap aluminium windows works when the savings come from the right places: a simple fixed or top hung window in a standard size can be both affordable and good. The risk is in what a low quote leaves out – safety glass, frame strength, finish and a written warranty – so compare those, not just the price.
Is 4 mm glass safe in aluminium windows?
4 mm float glass is not safety glass. It may be allowed in some window positions, but SANS 10400-N calls for safety glass in doors, low-level panes and other human-impact areas. Coetz™ windows come with 6.38 mm laminated safety glass as standard.
How long should aluminium windows last?
Well-made aluminium windows that are cleaned and maintained last for decades, while hardware and seals wear first and can be replaced. See aluminium window lifespan.
Why do cheap aluminium windows leak?
Usually because of poor seals, blocked or missing drainage holes, or a poor fit in the opening, rather than the aluminium itself.
How do I compare aluminium window quotes?
Put the quotes side by side and check the glass type and thickness, the frame size, the finish, the hardware, the warranty in writing, and whether delivery and VAT are included.
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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