uPVC vs aluminium windows, which suits an Irish house

1 September 2026 · The Home Upgrade Co.

Most Irish houses end up with uPVC, and most of the time that is the right call. Aluminium wins in specific situations, and they are worth knowing rather than being sold. This is the comparison without the sales pitch, including where we would tell you not to spend the extra.

The short version

uPVC for standard sized windows and better value. Aluminium where the opening is large and the frame width matters.

If you take nothing else from this: on a normal bedroom window the difference between the two is marginal and uPVC is better value. On a large rear opening where the view is the point, aluminium's slim frame is a visible, worthwhile difference.

A lot of houses end up with both, and there is nothing wrong with that.

Frame width is the real difference

Aluminium is stronger, so the same size opening needs less frame and gets more glass.

This is the honest reason to pay more for aluminium. The metal carries a bigger unit in a slimmer section, so on a large window you get noticeably more glass and a cleaner line.

On a small window there is little to see. The slim frame advantage only shows up when there is a lot of glass being framed, which is why it belongs on the big opening rather than throughout the house.

Thermal performance

uPVC is naturally a poor conductor, which helps it. Aluminium conducts heat readily and needs a thermal break to compensate.

An aluminium frame without a thermal break would be a cold bridge straight through the wall, with condensation on the inside face in winter. Any aluminium window worth fitting in Ireland is thermally broken, and it is worth confirming that is specified rather than assuming it.

With a proper thermal break the two perform comparably in a normal house. We do not publish figures here because they depend on the exact unit, and the specification goes in writing with your quote instead.

Colour and finish

Powder coated aluminium holds dark colours better than uPVC does over time.

Dark grey and black are what most people ask for now, and a powder coated finish holds that colour without the fading a dark uPVC surface can show after years of sun on a south facing elevation.

uPVC foils have improved a lot and are perfectly good, but if a dark colour on a very exposed elevation is the plan, aluminium is the more durable answer.

Maintenance

Both are close to maintenance free. Wash them, and keep the drainage slots clear.

Neither needs painting and neither rots. The one job that matters on both is keeping the drainage slots along the bottom of the frame clear, because blocked slots are what cause water to sit and eventually find a way inside.

Near the coast, rinsing salt off aluminium a few times a year is worth doing.

Cost, and where to spend it

Aluminium costs more. The sensible approach is to spend it where it shows.

Rather than committing the whole house to one material, put aluminium on the large rear opening or the elevation you look at, and uPVC on the bedrooms and the side windows nobody studies. Both come in matching colours, so the house still reads consistently.

We will price both on the same quote and tell you honestly where we think the difference is worth paying for. Our uPVC and aluminium pages have the detail on each.

What about timber?

Timber is the answer when planning requires it or when the house needs it, and it is a maintenance commitment.

On a protected structure or in an architectural conservation area, timber may be conditioned, and the profile may be specified too. That is a question for your local authority before anything is ordered.

Outside of that, it comes down to whether the look justifies the upkeep. See our timber windows page for the honest version.

Frequently asked questions

Is aluminium better than uPVC for an Irish house?

Not automatically. Aluminium wins on large openings where the slim frame gives you noticeably more glass, and uPVC is better value on standard sized windows where that difference barely shows.

What does thermally broken mean?

It means an insulating barrier is built into the middle of an aluminium frame so heat cannot pass straight through the metal. Any aluminium window worth fitting in Ireland is thermally broken.

Can I have aluminium at the back and uPVC at the front?

Yes, and it is a sensible way to spend the budget where it shows. Both come in matching colours so the house still reads consistently.

Which lasts longer in the Irish climate?

Both are close to maintenance free and neither rots or needs painting. Powder coated aluminium holds dark colours better over time, particularly on a sun facing elevation.