Aluminium versus plastic windows?

[Bobsyouruncle]

We have aluminium ranch sliders and windows all through our 70's house by the beach. All working perfectly. Why would you replace it with a 20 year life product????
Of course cold areas may be different but in Auckland why on earth would you bother for no benefit and lining up a huge bill before you die to replace them?? I don't get it at all.

[Lanthanide]

You haven't actually presented any evidence that it's a "20 year life" product. Only anecdote. Talking about products that are named uPVC in other countries is irrelevant, if the product named uPVC in this country is different.

Just like talking about aluminium windows in other countries is irrelevant, if those windows are constructed differently to the ones available in New Zealand.

Here's a local website that talks about uPVC windows in NZ: http://homerit.co.nz/why-pvc-u-windows/long-lasting/

[Bobsyouruncle]

Come back and tell us in 20 years. I've checked forums and non marketing sites in OZ, NZ, UK and USA. ALL NZ windows are imported so the deal is the same. THe info is pretty consistent. The UPVC itself will last but other parts of the windows fail. 40 years is a good theoretical timeframe, still being less than half of Ali or timber. However people in all 4 countries have issues within 10 years. A LOT of them. So why risk it for no benefit.

[Bobsyouruncle]

This is from a research university study in the UK.

Table 2 Survey analysis results

Window(frame type)	Estimated service life			[IMG]file:///page10image5056[/IMG] Characteristics [IMG]file:///page10image5824[/IMG]
Mean	Median	Inter-quartilerange
Aluminium	43.6	40	12.5	Low maintenance
PVC	24.1	22.5	15	Low maintenance, difficult torepair
Timber	39.6	35	16.3	High maintenance, easy torepair
Al-clad Timber	46.7	45	10	[IMG]file:///page10image24888[/IMG] Low maintenance, easy to repai

[Lanthanide]

Where's the link to the study?

Found it:

http://ohp.parks.ca.gov/pages/1054/files/uk%20window%20frame%20lca.pdf

The windows surveyed were PVC, not uPVC. Not the same thing, sorry. It was also published in 2002. Technology has moved on since then.

http://www.bpf.co.uk/enviromental_matters/Life_of_a_PVC_U_Window.aspx

From the linked PDF:

The Green Guide uses 25 years as the typical service life for PVC-U windows which translates tinto the environmental burdens from initial installation and two further replacements during the 60 year life cycle assessment period. The service life was based on information available at the time of the publication of the guide.

The British Plastics Federation (BPF) commissioned BRE to examine new evidence an to review the serivce life of 25 years for PVC-U windows.


With the help of BPF, BRE identified a representative sample of PVC-U window manufacturers that together provide some 80% of the manufactured product in the UK. These were sent a questionnaire requesting evidence of the service lives of their products.


BRE has found strong evidence, provided by the VPF and its member manufacturers that PVC-U windows show now expect to have a (reference) service life of at least 35 years under normal urban and non-aggressive conditions. This conclusion has been supported by a desk analysis of common serice life data sources.

PVC-U windows now account for 85% of the market of new and replacement windows in the UK.

Now the obvious difference between the UK and NZ is the UV exposure, but the point I'm making is that technology has improved since your study done in 2002, which had no idea what the composition of the PVC windows they studied were.

[Thinkingbutnotdoing]

Why replace 70s aluminium ranchsliders? Because they are stuffed from 35 years (in my case) of use, and need a lot of work to repair them at the end of which they'll still be bendy and single glazed. (Remember also we have been through a few EQs and things are not quite square anymore - which means there are gaps.) The windows are on the second floor and do not have safety glass (though we are not replacing those ones this time as the windows are still fit for purpose).

[Bobsyouruncle]

You need to read what I said. I will replace them with new aluminium. I don't want to replace them again in 20 years. That's stupid.

[Learning]

We replaced six of our timber framed windows with uPVC double glazing five years ago. We're very happy with the product so far.

We had lived a few years in the U.K. so were fimilar with the product. Basic alumni frames would of been cheaper but with thermal transfer you've still got condensation on the frames. Thermal broken alumni was more expensive and had none of the 'free' extras.

Our uPVC frames came from Germany. The double glazed window cassettes were made locally. (Same glass supplyer as our local alumni gets from). 5 point locking system, key locks, lockable ventilation gap (2cm) all standard. Child locks $20 each (10cm opening). 80 degrees opening angle when fully open.

Two of our friends have the same from the same supplier, one older install and one more recent, and we've discovered all the window keys are exactly the same. So sort of defeats that security.

[Lanthanide]

Two of our friends have the same from the same supplier, one older install and one more recent, and we've discovered all the window keys are exactly the same. So sort of defeats that security.

Locks are only for keeping honest people out. If people want to get into your house, they'd break the glass.