The short answer
Aluminium wins on durability, maintenance, and long-term value. Steel wins on nothing, unless your budget cannot stretch beyond a short-term patch. If your steel frames are 15+ years old and showing rust, replacement is cheaper over 5 years than continued repair.
The real comparison
Most homes built from the 1940s through the 1990s across the West Rand, Krugersdorp, and greater Gauteng were fitted with steel window frames. For decades, steel was the standard. It was affordable, available, and it worked. But Highveld weather has taken a toll on those frames, and the older homes carry a real vintage character that is worth protecting with a proper modern upgrade.
Here is how the two materials actually compare in practice:
| Factor | Steel Frames | Aluminium Frames |
|---|---|---|
| Rust resistance | Rusts from the inside out. Requires regular sanding and repainting. | Does not rust or corrode. Zero maintenance. |
| Lifespan | 15-25 years before major deterioration | 30-50 years with no structural decline |
| Weight | Heavy. Limits opening size. | Lightweight. Allows wider spans and bigger openings. |
| Thermal performance | Poor. Single-pane glass is standard. | Better. Can accommodate double glazing. |
| Maintenance | Needs repainting every 2-3 years. Putty cracks and needs replacing. | Wipe down occasionally. Nothing else. |
| Security | Adequate when new. Weakens as rust sets in. | Multi-point locking systems available. Stays strong. |
| Resale value | Dated look reduces buyer appeal. | Modern finish increases property value. |
| Cost (installed) | R800-R1,500 per window (repair/repaint) | R2,500-R6,000 per window (new install) |
When to replace steel frames with aluminium
Not every steel frame needs replacing. If your frames are still structurally sound, with minimal rust and no warping, a repaint can buy you another 3-5 years.
Replace when you see any of these signs:
- Rust bubbling under the paint surface (the frame is corroding from inside)
- Frames that no longer close flush or seal properly
- Visible gaps between the frame and the wall
- Putty that has cracked and fallen out, leaving glass loose
- Condensation between panes (if double-glazed) indicating seal failure
- Difficulty opening or closing windows and doors
If two or more of these apply, repair costs will exceed replacement costs within 2-3 years.
The cost reality for SA homeowners
The upfront cost of aluminium is higher. A full home window replacement (8-12 windows) typically runs R25,000 to R60,000 depending on sizes and specifications. A steel frame repaint for the same home might cost R5,000 to R12,000.
But here is the catch: you will repaint those steel frames again in 2-3 years. And again after that. Over 10 years, the total cost of maintaining steel often exceeds the one-time cost of switching to aluminium. And aluminium gives you a property that looks better, feels better, and is worth more when you sell.
What about uPVC?
uPVC (plastic) frames have become popular in South Africa. They are cheaper than aluminium and do not rust. However, they expand and contract significantly in the Highveld heat, discolour over time in direct sun, and cannot support the same span widths as aluminium. For most residential applications in Gauteng, aluminium is the better long-term choice.
How the process works with Alu-Value
- Free on-site measure. We come to your property, assess the existing frames, and measure every opening.
- Quote within 48 hours. Clear pricing, no hidden costs. We explain exactly what you are getting.
- Manufacturing. Frames are manufactured to your exact measurements. No off-the-shelf sizing.
- Installation within 15 working days. Our own team installs. No subcontractors.
- Final payment after installation. You only pay the balance once the work is done and you are satisfied.
Every installation is backed by our 2-Year Installation Guarantee. Alu-Value has been on the West Rand since 1996 and based at 96 Rustenburg Road, Krugersdorp since 2010. We are not going anywhere.
Ready to get a quote?
If your home still has the original steel frames, whether it is a 1940s vintage build or a 1990s suburban family home, it is worth getting a professional assessment. We will tell you honestly whether replacement makes sense now or whether a repair will hold for a few more years.
Get a free quote on WhatsApp or call us at 082 550 3115.