Aluminium has largely replaced steel as the default window material in new South African homes. Here is why, and whether steel still has a place.
The case against steel windows
Traditional steel windows rust. The paint system on a steel window degrades under UV, moisture gets underneath and oxidation begins. Once started, rust in steel window frames is difficult to stop without stripping back to bare metal, treating and repainting - work that needs to be repeated regularly. In Bloemfontein, where summer afternoon thunderstorms alternate with months of dry UV exposure, steel windows deteriorate faster than coastal areas.
Why aluminium performs better
Aluminium does not rust. When exposed to air, it forms a thin oxide layer that actually protects the metal beneath - unlike iron oxide (rust), which is porous and accelerates the corrosion underneath. Aluminium frames are powder-coated rather than painted, which is more durable and UV-resistant than paint. The result is a window that looks good and seals well 20+ years after installation with basic cleaning.
Thermal performance
Standard single-pane aluminium windows conduct heat and cold readily - aluminium is a good thermal conductor. In Bloemfontein's cold winters and hot summers, this means heat loss in winter and heat gain in summer is higher than with timber or uPVC framing. Thermally broken aluminium frames (with an insulating material between inner and outer sections) significantly reduce this. Double glazing further improves performance.
Steel windows still have a place
In heritage properties and restored older homes in suburbs like Westdene and Arboretum, replacing steel windows with aluminium changes the architectural character. Some property owners restore original steel windows rather than replace them - a specialist job requiring lead paint removal precautions on very old frames. For all new installations, aluminium is the practical choice.
Frequently Asked Questions
Can aluminium windows be made to look like steel windows in a heritage home?
Yes. Slim-section aluminium profiles can approximate the look of traditional steel windows and are available in black powder coat finishes. The architectural result is similar; the maintenance requirements are far lower.
How long do aluminium windows last?
Quality aluminium windows with proper powder-coat finish last 30–40 years with basic maintenance. The glass and seals may need attention sooner than the frames.
Need professional help?
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Aluminium & Glasswork in Bloemfontein