uPVCorSystemAluminium:ADesigner'sGuidetoWindowsinIndia

Two materials, one decision

A window is the hardest-working detail in a facade. It has to stop water, wind, dust, noise and heat at the same time, and it almost never fails at the glass. It fails at the joint, the gasket and the fixing. That is why the choice between uPVC and system aluminium is really a choice about how a frame is engineered and who stands behind it, not about the material alone.

Across ten years of specifying fenestration for homes from Hyderabad to the Konkan coast, the first thing I ask a client to do is separate two words that get used loosely: uPVC and aluminium. One is a plastic profile. The other, done properly, is an engineered system. Confuse either with the cheap sliding window from a local fabricator and you will pay twice, once to install it and again to replace it.

What actually separates uPVC from system aluminium

uPVC is unplasticised polyvinyl chloride, extruded into a multi-chamber profile and reinforced inside with galvanised steel. The chambers trap air, so it insulates well and stays quiet. It does not rust, rot or conduct much heat, and it sits in the middle of the price range. Its limits are physical. Profiles read as visually heavier, section sizes are finite, and very large openings need extra mullions or the sash begins to flex.

System aluminium is a different proposition. A single manufacturer designs a matched family of profiles, gaskets, drainage paths, hardware and a thermal break, then tests the whole assembly for air, water and wind performance. You buy the tested system, not a length of metal. It gives slim sightlines, carries large spans and heavy glass, and reads as architecture. Bare aluminium conducts heat, so any serious residential system uses a polyamide thermal break to slow that transfer.

The distinction that matters on site: system aluminium is not the fabricated aluminium sliding window sold by weight. That older product has no thermal break, thin gaskets and no test data behind it. Everywhere this guide says aluminium, it means the engineered systems named below.

The coastal question: salt, sun and the thermal break

On the coast the rules change. Salt-laden air is the most aggressive thing a window faces in India, and it settles the question of longevity more firmly than any brochure figure.

uPVC has one clear advantage here: it is chemically inert to salt, so it will not corrode in Visakhapatnam, Chennai or Kochi. Its weakness is the sun. Sustained UV and heat can, over years, chalk or slightly fade lower-grade profiles, so specify one with proven UV stabilisers, and in dark colours ask for documented heat resistance.

Aluminium can outlast everything on the coast, but only if it is finished for it. Ask for marine-grade treatment: a Qualicoat Seaside class powder coat at 60 to 80 microns, or architectural anodising, not a thin decorative coat. Hardware should be stainless steel, ideally grade 316, because ordinary rollers and friction stays are the first parts to seize in salt air. A thermal break earns its place in air-conditioned coastal homes for a second reason beyond energy: it keeps the inner frame warm enough to stop condensation forming on the metal.

uPVC brands worth specifying

For uPVC, understand one split before you choose. Some names sell you a finished, installed window and own the whole chain. Others sell only the profile, and you buy the completed window from an authorised fabricator, whose workmanship then matters as much as the label on the frame.

System aluminium brands worth specifying

System aluminium is where the European and Japanese houses lead, with Indian systems now genuinely credible at the accessible end. Here a fabricator is always part of the deal, because even Schueco is only as good as the workshop that cuts and assembles it. Insist on a fabricator approved by the brand and working with its tooling, then check a reference project before you commit.

What it costs, fully fitted

The figures below are indicative for 2026, per square foot, supplied and fitted, before GST, for a normal-access ground or low floor. Glass specification, colour, hardware and site conditions move them significantly, so treat them as bands, not quotes.

As a working rule: good uPVC lands between Rs 450 and Rs 1,300 per square foot fitted. Standard fabricated aluminium sits around Rs 1,000 to Rs 1,400 and buys you little in performance. Real system aluminium with a thermal break runs Rs 1,800 to Rs 3,500, and beyond it for the top German houses. Seasoned hardwood overlaps the upper band and asks for the most upkeep of the three.

Maintenance, without illusions

Maintenance is where the honest differences show, and where clients are most often surprised.

uPVC asks for very little. Wash the frames a few times a year, keep the drainage weep holes in the sill clear so water never pools, and lightly oil the hinges and locks once a year. The profile itself needs nothing else.

System aluminium is similarly low-effort but finish-dependent. On the coast, rinse the frames with fresh water every one to two months to lift salt deposits before they etch the coating, and have the rollers and gaskets serviced once a year. A good marine-grade powder coat or anodised finish then holds its colour for decades.

Wood is the demanding one: reseal or repaint every three to five years, and expect some swelling in the monsoon and movement in the dry heat. It is the most beautiful option and the only one that is a standing commitment rather than a fitting.