Windows: uPVC vs Aluminium vs Timber
What they are
- uPVC: Rigid vinyl frames with multi-chambers; steel/aluminium reinforcements where needed.
- Aluminium (thermally broken): Slim metal frames separated by an insulating “thermal break.”
- Timber (engineered wood): Laminated wood sections; often factory-finished. (Bonus: Alu-clad Timber = timber inside, aluminium cap outside.)
Quick take
- Thermal: All three can meet low U-values; aluminium needs thermal breaks to compete.
- Aesthetics: Aluminium = slimmest sightlines; timber = warm, premium; uPVC = clean, value.
- Durability & upkeep: uPVC low maintenance; aluminium long life/paint stability; timber needs periodic care (unless alu-clad).
- Spans: Aluminium best for large panes/sliding doors; timber next; uPVC least stiff (more profiles/transoms).
- Acoustics: Heavier frames + laminated glazing win (any material); timber/uPVC frame mass helps slightly.
Pros & cons
uPVC
- Pros: Great value, very low maintenance, good thermal/acoustic performance, corrosion-proof near coast.
- Cons: Bulkier profiles, limited colours/finishes vs aluminium, thermal movement needs careful detailing in large spans.
Aluminium (thermally broken)
- Pros: Slim frames, crisp modern look, high strength for large openings, excellent colour stability (powder coat/anodise), fire-friendly for façades where required by code.
- Cons: Needs quality thermal breaks & gaskets to avoid condensation; coastal sites need marine-grade coatings.
Timber (engineered)
- Pros: Warm, natural finish, good thermal performance, easy to repair/refinish, sustainable when sourced responsibly.
- Cons: Requires periodic maintenance (recoat intervals), sensitive to detailing in sun/wet exposures; movement with humidity.
Alu-clad Timber (hybrid)
- Pros: Timber interior feel + aluminium exterior durability; reduced maintenance.
- Cons: Highest upfront %, more complex joinery details.
Performance notes (frame + glazing as a system)
- Energy: Low-E double/triple glazing, warm-edge spacers, airtight installation drive most gains; frame choice fine-tunes results.
- Condensation control: Thermal break (Alu), multi-chamber (uPVC), and correct interior humidity/ventilation.
- Security: Multi-point locks, reinforced frames, laminated panes; similar across materials when spec’d correctly.
- Fire/smoke: Check local code; aluminium systems commonly used in façade assemblies; timber/uPVC may need specific ratings in stair cores/escape routes.
- Coastal/UV: uPVC and marine-grade aluminium both work; timber needs rigorous finishing & detailing.
Costs (percentages only; baseline = uPVC = 0%)
(Supply + typical install for comparable sizes and spec; varies by glazing, hardware, opening type, and finish.)
- Standard thermally-broken Aluminium: +25–60% vs baseline
- Premium slimline Aluminium / large sliders: +60–120% vs baseline
- Engineered Timber (factory finished): +20–50% vs baseline
- Alu-clad Timber (hybrid): +50–100% vs baseline
Lifecycle & maintenance over ~10–15 years
- uPVC: −10–25% vs baseline painted timber (least upkeep)
- Aluminium: −15–30% vs baseline (wash + occasional hardware service)
- Timber (exterior paint/oil cycles): +10–30% vs baseline
- Alu-clad Timber: 0–10% vs baseline (exterior cap cuts maintenance)
Programme/installation (time impact)
- Aluminium large sliders/curtain modules: +10–25% vs baseline (heavier handling/alignment)
- Timber with on-site finishing: +10–20% vs baseline (if not factory finished)
Benefits (owner outcomes)
- uPVC: Best value thermal upgrade, quiet rooms, minimal upkeep.
- Aluminium: Contemporary lines, large glass areas, colour/finish stability, robust sliders/bi-folds.
- Timber: High-end feel, tactile interiors, easy to refinish/change colour, heritage approvals.
- Alu-clad Timber: Premium interior + durable exterior for harsh climates.
Risks & how to avoid them
- Poor installation (all): Air/water leaks, racking. → Use level plinths, packers, perimeter membranes, tested installers.
- Thermal bridging at frames (aluminium): Cold edges/condensation. → Specify high-quality thermal breaks, foam inserts, warm-edge spacers, proper interior seals.
- UV/chalking (uPVC low grade): Discoloration. → Choose UV-stabilised profiles from top brands.
- Finish failure (timber): Peeling at sills/exposed faces. → Factory finish, drip edges, correct sill pitches, scheduled recoats.
- Coastal corrosion (aluminium): Pitting at fixings/edges. → Marine-grade coatings/fasteners; rinse schedule near surf.
- Sound leaks (all): Weak seals. → Double gaskets, laminated glass, correct trickle vents if required.
Quick choice guide
- Value + low maintenance (most homes): uPVC
- Slim frames + large spans/modern look: Thermally-broken Aluminium
- Warm natural interiors/heritage: Engineered Timber
- Premium hybrid in harsh climates: Alu-clad Timber
Spec tips (Dubai & hot climates)
- Low-E solar-control glazing to cut heat gain; consider laminated panes for acoustics/safety.
- Trickle ventilation or mechanical ventilation to manage indoor humidity and reduce condensation.
- Shading (overhangs/external screens) improves comfort regardless of frame type.
- Hardware: choose corrosion-resistant hinges/rollers, especially near the coast; multi-point locks on sliders.
One-line FAQ
- Do aluminium windows always lose on insulation? No—modern thermally broken systems with quality glazing can match typical residential targets.
- Can uPVC do large sliders? Possible, but aluminium is usually better for very wide/heavy panels.
- Does timber survive in hot, sunny climates? Yes—with factory finishing, proper detailing, and scheduled recoats; alu-clad reduces exposure.
