Choosing between aluminium vs wooden windows is really a choice about how much maintenance you are willing to do. Both materials work well in Cape Town. They just ask very different things of you over the twenty years you own them.
Here is the practical comparison, without the sales pitch.
Aluminium vs wooden windows on upfront cost
Aluminium generally costs less to buy. Standard frames from major suppliers start at roughly R1,050 for a small unit, and fitted sliding windows are commonly quoted from R1,500 to R4,000 each.
Hardwood frames of a similar size typically cost more, and the gap widens as the units get bigger. Meranti sits at the affordable end of timber, with hardwoods well above it.
If the budget is the deciding factor and the openings are large, aluminium usually wins on day one.
The maintenance gap is the real difference
This is where the two materials genuinely part ways.
Powder-coated aluminium needs washing. That is close to the whole job. Rinse off salt and dust, keep the drainage holes clear, and check the seals every year or two.
Timber needs sanding and resealing or repainting on a cycle. In a sheltered inland suburb you might stretch that to five years. On an exposed coastal elevation facing the southeaster, it can be every two to three years.
Over two decades that difference is thousands of rands and a lot of weekends.
Coastal durability
Cape Town is a salt air city. That single fact settles the argument for a lot of homes.
Aluminium does not rot and does not swell. It can develop surface pitting if it is never cleaned, but it will not fail structurally.
Timber swells in wet winters and shrinks in dry summers. Windows that stick in August and rattle in February are the usual symptom. Once the seal coat is breached, moisture gets into the grain and rot follows.
Untreated steel is the worst option near the sea and is best avoided entirely.
Insulation and comfort
Here timber has the honest advantage. Wood is a natural insulator. Aluminium conducts heat, so a large aluminium window on a north or west face will transmit more heat than a timber one of the same size.
In practice this matters less in Cape Town than in a very cold climate, and it is usually solved with shading, overhangs or better glass rather than by choosing timber.
If you want the thermal performance of timber with the upkeep of aluminium, aluminium-clad timber exists. It costs considerably more than either.
Looks and heritage
Timber suits period properties. On a Victorian or Cape Dutch home, slim timber sashes look right and aluminium often does not. Some heritage overlays will also require you to match the original.
Modern aluminium sections are slim and come in a wide powder-coat range, which is why they dominate contemporary builds and large glazed openings. If you want a big stacking or folding door, aluminium is the practical choice.
So which should you choose
Choose aluminium if you want low upkeep, you are near the coast, you have large openings, or you simply do not want to repaint frames every few years.
Choose timber if you have a heritage home, you want the warmth of real wood, and you accept a regular maintenance cycle as part of owning it.
For most Cape Town homes we are asked to quote on, aluminium is the sensible answer. We install aluminium doors and windows across the city and quotes are free. See finished installations in the gallery, browse our services, or look at current aluminium window prices before you decide.
Already committed to aluminium and near the sea? The coastal care guide explains how to keep frames in good order.
The twenty year cost, not the day one cost
Comparing quotes on purchase price alone hides the real difference. Timber carries a repainting cycle. Assume sanding and resealing every three to five years depending on exposure, priced per window, for as long as you own the house.
Aluminium carries close to nothing beyond cleaning. Over two decades that gap routinely exceeds the original price difference between the two materials, which is why the cheaper-looking option on day one is often the more expensive one overall. Current figures are in our window price guide.
Mixing materials in one house
You do not have to choose one material for the whole property, and on some homes you should not.
A common approach on a period house is timber to the street-facing elevation where the look matters and heritage rules may apply, with aluminium to the rear and to large new openings onto a patio or garden. That keeps the character at the front and the low maintenance where nobody is looking.
It is worth thinking about this at design stage rather than later. If you are already planning work, the sequencing is covered in our renovation budget guide, and you can see both materials in finished projects in the gallery.
Frequently asked questions
Which lasts longer, aluminium or wooden windows?
Well maintained timber can last as long as aluminium, sometimes longer. The difference is that aluminium reaches a long life with almost no work, while timber only gets there if you keep resealing it on schedule.
Are aluminium windows bad for insulation?
Aluminium conducts more heat than timber, so it is the weaker insulator. In Cape Town the practical fix is shading and appropriate glass rather than switching material.
Can I put aluminium windows in a heritage home?
Sometimes, but not always. Heritage overlays often require you to match the original profile, and slim timber sashes are difficult to replicate in aluminium. Check with the local authority first.
Which is better near the sea?
Aluminium, in most cases. It does not rot or swell, and salt air only causes surface marking that regular rinsing prevents. Timber needs a much tighter maintenance cycle on exposed coastal elevations.
Is aluminium cheaper than wood?
Usually yes, both to buy and to own. Timber can be competitive on small windows but the gap widens on large openings, and timber carries an ongoing repainting cost that aluminium does not.
