Aluminium vs uPVC vs timber windows: choosing the right fram

Aluminium vs uPVC vs timber: choosing the right window frame

Aluminium is the cheapest and most durable per dollar — best for coastal exposure and modern aesthetics. uPVC offers the best thermal performance per dollar — the right choice if energy efficiency is the top priority. Timber suits heritage and character homes where the streetscape and the building’s age justify the higher maintenance and price. The right answer depends on your home’s age, location, exposure, and how long you’ll own it.

The frame material question is the second decision after “do I need new windows or can I retrofit”. Get the frame material right and the rest of the spec falls into place; get it wrong and you’ll regret the choice every time you go to clean the window or pay the heating bill.

The three options, in plain terms

Aluminium — extruded metal frame, powder-coated finish. Strong, light, immune to rot and termites. Conducts heat readily (cold to touch in winter, hot in summer) unless thermally-broken.

uPVC — unplasticised polyvinyl chloride. A multi-chamber polymer profile. Excellent thermal performance because the polymer doesn’t conduct heat. Common in Europe; growing fast in SA.

Timber — historically western red cedar, Victorian ash, or kauri pine. The original window frame material. Looks the part on heritage and character homes; needs maintenance every 5–8 years.

Cost — apples to apples

For a standard 1200×1500mm awning window, fitted, in 2026:

Material	Price band
Aluminium single-glazed	$1,000–$2,200
Aluminium double-glazed	$1,800–$3,800
uPVC double-glazed	$2,500–$5,000
Timber casement single-glazed	$1,800–$3,500
Timber casement double-glazed	$2,800–$5,800

uPVC is rarely worth specifying as single-glazed — the thermal win comes from the combination of frame and glazing.

Thermal performance — frame matters more than people think

A double-glazed unit in an aluminium frame loses up to 40% of its theoretical thermal performance through the frame itself. The same unit in a uPVC frame retains 85–95% of theoretical performance. In real numbers:

System	U-value (W/m²K)
Single-glazed aluminium	6.5
Double-glazed aluminium	3.5
Double-glazed thermally-broken aluminium	2.5
Double-glazed uPVC	1.8–2.2
Triple-glazed premium uPVC	1.0–1.4

If energy efficiency is the priority, uPVC with double-glazing wins per dollar.

Durability — different definitions

Aluminium and uPVC are essentially zero-maintenance. Powder-coated aluminium lasts 30+ years with no attention; quality uPVC lasts 25+ years. Both ignore termites and rot.

Timber needs attention. A well-finished timber window with a quality external coating needs re-coating every 5–8 years. Cheaper timber, poor original finishing, and harsh exposure can bring that to every 3–5 years. Done well, timber lasts 50+ years; done poorly, it can fail in 10.

Coastal exposure

For homes within 5km of the coast — Glenelg, Henley Beach, West Lakes, Brighton, Aldinga — salt accelerates wear on cheap aluminium. Marine-grade aluminium (a higher-spec extrusion with better coatings) is the right choice; standard aluminium’s powder-coat can chalk and discolour within 5–8 years on direct salt exposure. Marine-grade extrusion costs ~15% more.

uPVC is largely unaffected by salt. Timber, properly finished, can last 30+ years on the coast — but only if the coating discipline is rigorous.

Heritage and character homes

For Federation, Edwardian, and Victorian homes in heritage overlay zones, timber is usually the only sympathetic choice — and increasingly, the only choice the council will approve for street-facing windows. Modern profiled timber windows can accept double glazing without losing the heritage detail; we run that conversation as part of the on-site measure.

For 1960s–1990s homes outside heritage overlay, all three materials work. uPVC’s growing visual acceptance means it’s increasingly a valid choice even on character homes.

What we install most in Adelaide

Rough split, 2026:

• Aluminium: ~50% (cost-effective, salt-rated, every aesthetic style)
• uPVC: ~30% (energy-conscious owners, growing fast)
• Timber: ~20% (heritage and architectural)

Decision framework

Three questions:

1. What’s your priority — cost, thermal, or aesthetics?
   • Cost: aluminium
   • Thermal: uPVC
   • Aesthetics on a heritage home: timber
2. How long will you own the home?
   • <5 years: aluminium probably
   • 5–15 years: uPVC, recover the energy premium
   • 15+ years or forever home: best fit per priority
3. Coastal or BAL exposure?
   • Coastal: marine-grade aluminium or premium uPVC
   • BAL-FZ: certified system in any of the three; depends on overlay

Getting it right at the on-site measure

The right call comes from looking at the existing windows, the streetscape, the orientation, and the overlay constraints. We bring sample profiles to every measure visit so you can compare the three side-by-side against your existing windows. Request a quote →