Once you have decided on double glazing, the next choice is the frame, and for most homeowners that means aluminium or uPVC double glazing. The glass in the sealed unit can be much the same in both, so the frame material is what changes the warmth, the look and the price. This guide compares the two fairly, so you can pick the one that suits your home rather than the one a salesperson pushes hardest.
Both are excellent, modern choices. uPVC is warmer for the money and the most affordable option, which is why it is on so many homes. Aluminium is stronger and lets you have slimmer frames and bigger glass, at a higher price. Neither is "better" in every way. It depends on what you want from the windows.
This is where a lot of the old myths live, so it is worth being clear.
In practice, both can meet current energy standards comfortably. If squeezing the best warmth from the smallest budget is the priority, uPVC has the edge. If you want the aluminium look with strong performance, the thermal break gets you there.
This is where aluminium shines. Because the metal is strong, the frames can be much slimmer while still holding large panes of glass. That gives you more glass, less frame and a clean, contemporary look that suits modern homes and extensions beautifully.
uPVC frames are chunkier by comparison, though modern designs are slimmer than the old ones and come in a wide range of colours and woodgrain finishes. For period and traditional York homes, that softer look often fits better anyway. For a sharp, minimal, big-glass feel, aluminium wins.
Our aluminium windows page shows the slimline frames in real installations, and the uPVC windows range shows the styles and finishes on the warmer-value side.
As a rough 2026 guide, supplied and fitted per window:
Aluminium typically costs more, often noticeably so, because of the material and the thermally broken frame. Over a whole house that difference adds up, so it is worth being honest with yourself about how much the slim look matters versus the budget. These are guide ranges, and size, glass spec and access all move the figure, so get a quote before you plan firmly.
Both last a long time and neither needs much looking after. A wipe with soapy water keeps them clean. uPVC can be prone to discolouring over many years on very sunny elevations, though good modern uPVC resists this well. Aluminium holds its powder-coated colour for a long time and is very tough, which is part of why it costs more. Either way, you are buying windows that should serve you for decades.
Choose uPVC if you want the best warmth for your money, a wide choice of colours, and a look that suits a traditional or period home. It is the sensible, value choice for most houses.
Choose aluminium if you want the slimmest frames, the biggest glass, and a modern look, and the budget allows for it. It is the premium choice for contemporary homes and statement windows.
If you are mixing styles across the house, there is no rule that says you cannot use uPVC on the bedrooms and aluminium on a big feature window downstairs. A good installer will help you get the balance right.
uPVC is naturally a good insulator and tends to give strong warmth for the price. Aluminium conducts heat, but modern frames use a thermal break to insulate well. Both meet current energy standards, though matching uPVC's warmth in aluminium usually costs more.
Because the material costs more and the frames use a thermal break to insulate properly. You are also paying for slimmer sightlines and the ability to hold larger panes of glass. Over a whole house the difference is significant, so get a quote to compare.
Yes. Aluminium is strong, so the frames can be much slimmer while still holding large glass panels. That means more glass and less frame, which is why it suits modern homes. uPVC frames are chunkier, though newer designs are slimmer than older ones.
Both last decades with very little upkeep. Aluminium is extremely tough and holds its powder-coated colour for a long time. Good modern uPVC resists discolouring well too. For most homes, lifespan is not the deciding factor, so choose on warmth, looks and budget.
Want to see both frame types up close? Download our latest brochure, or request a free quote and we will pop out for a look.