Timber or PvC Sash Windows

karlsoden

Hi

Im looking to buy sash windows at the moment and need to achieve a u value of 1.4 or lower for an SEAI grant, is this possible and can anyone recommend companies that would meet the low u value in the sash style.

I prefer the look of timber frames but from what I've been told they can't achieve the lower u values of PvC. Is this correct?

thanks

C. Eastwood

https://www.boards.ie/discussion/2058259585/timber-or-pvc-sash-windows

uPVC will give you 40 years maintenance free. Timber will shrink and expand and twist with the relative humidity and will need painting every few years. Painting timber windows is very time consuming. Buy uPVC.

awec

https://www.boards.ie/discussion/comment/119503461#Comment_119503461

Wouldn't agree with this at all, timber (or alu-clad) will look far better than PVC. PVC will make your sash windows look cheap.

bemak

you can get very good uPVC windows now that have a bit of 'grain' in them - they look very convincing to be fair.

C. Eastwood

https://www.boards.ie/discussion/comment/119504445#Comment_119504445

Timber is Hygroscopic.

awec

https://www.boards.ie/discussion/comment/119506191#Comment_119506191

Yes, that is why you maintain them.

Using PVC for a sash window, which is a traditional window style, is going to look wrong IMO. PVC windows are generally the cheapest option and they will look it.

pjdarcy

From what I understand you can achieve low U-values with any of the available window frame materials but uPVC will have better performance (i.e. a lower U-value) at a price point compared to other available materials.

Lumen

Not sure you'll achieve the required u-values with timber, but if you don't mind having them painted them on the inside, Accoya is worth considering.

Yellow_Fern

https://www.boards.ie/discussion/comment/119503461#Comment_119503461

I want to stress it depends on the location. A very exposed south facing window wont last as long as a more sheltered one. I have seen windows frames that are grand after 70 years of abandonment on the right location.

You can easily get wooden windows of 1.4 U-value now.

If the building is listed (Dublin Corpo have listed entire roads/areas) you may only be allowed to use period wooden sash windows. We had issues with them when renovating a house and used uPVC sash windows. Argued and kept them in the end, looked better than most of the other houses on the road, many with old aluminum single glazed windows.