Both are good products. They are good at different things — here is how to decide based on your span, your budget and which way your wall faces.
Almost every enquiry we get starts with the same question, and the honest answer is that neither material wins outright. They fail and succeed in different places. Here is how we decide on site.
Thermal performance
uPVC wins, and it is not close. Plastic conducts heat poorly, and a multi-chambered profile traps still air inside the frame itself. Aluminium conducts heat about a thousand times better than uPVC, which is exactly what you do not want in a window frame.
A thermal break closes most of that gap. A polyamide strip splits the profile into an inner and an outer half so heat cannot simply walk across the metal. A thermally broken aluminium window is a genuinely efficient product — but it will still trail an equivalent uPVC window, and it will cost more.
Span and sight lines
Aluminium wins, and again it is not close. Steel-reinforced uPVC is strong, but there is a size beyond which the frame has to get visibly fatter to stay rigid. Aluminium carries the same load in a much slimmer section.
So if the drawing shows a three-metre-tall sliding panel, or the architect wants a 40mm sight line, that is an aluminium job. A 4ft × 4ft bedroom window is not.
Cost
For a standard residential opening, uPVC typically lands 20–35% below thermally broken aluminium. The gap narrows as sizes grow, because uPVC needs more reinforcement to get there.
Maintenance
Both are low maintenance. uPVC needs nothing but soap and water. Powder-coated aluminium needs the same, though coastal air is harder on it and marine-grade coating is worth specifying within 30km of the sea.
How we usually split a house
On a typical Delhi NCR project we specify uPVC for bedrooms, bathrooms, kitchens and utility areas — every ordinary opening, where the thermal and acoustic gains matter most and the sizes are modest. Then aluminium for the living room slider onto the terrace, the stairwell picture glazing and anything above about 2.4 metres tall.
That mix usually gives the best result per rupee. If you would like it worked out for your own drawings, send them across and we will mark up a room-by-room recommendation.
