uPVC windows, a good idea or not « Alternative Technology Assn Forums

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uPVC windows, a good idea or not

(44 posts) (20 voices)

Started 1 year ago by Bernardo
Latest reply from Sonja

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Bernardo
Member

I was about to install uPVC windows for energy efficiency but am having second thoughts.

I've just come across reports suggesting a range of problems --- that sunlight discolours the frames and makes them brittle, that they are not necessarily free of maintenance, that misting can occur in the sealed glass section, that they're made from some nasty chemicals and it's unclear whether or not they emit some of these during their life span.

Some reports refer to low quality uPVC frames but how can a consumer distinguish? Are uPVC windows simply not a good idea after all?

Any thoughts?

At this stage, I'm leaning back towards timber.

These windows seem to combine the function of uPVC windows with the known quantity that is timber --- http://www.paarhammer.com.au --- but I suspect they are pricey.

Anyone know if any similar suppliers in Sydney?

Thanks

Posted Thursday 12 May 2011 @ 10:29:15 am from IP #
dymonite69
Member

I have heard that Kommerling, Rehau and Deceuninck are reputable but expensive Euro brands with warranties. Some of these have been tested in harsh conditions.

Misting would seem to be a problem of not having a dessicant in the air gap.

Framing design and hardware quality can significantly alter price e.g. hinges, locks

You could use composite frames with the durability of aluminium externally and the insulation of timber on the inside.

I have also seen a house in Sustainable house day that used aluminium DG frames but asked the builder to place timber infills on the inside of the frame prior to plastering and flushing.

Posted Friday 13 May 2011 @ 11:46:48 am from IP #
Catopsilia
Member

Bernardo
My information is now well out of date. I wrote to Renew about it in 1999(?).
I have been very satisfied with my Rylock double-glazed units built with aluminium frames that are concealed by woodwork on the inside. They were very much cheaper than the uPVC units on the market at that time, and also cheaper than wooden units.
It has always seemed to me that exposed woodwork is bound to need maintenance.

Posted Friday 13 May 2011 @ 12:50:20 pm from IP #
Bernardo
Member

Thanks dymonite & catopsilia,

The uPVC windows I've been looking at are based on Kommerling material. I'm still a little spooked, however, by the thought they may emit nasty chemicals. Perhaps this fear is exaggerated, I don't know.

I'll have a look at the Rylock units, too.

I think the Paarhammer windows are terrific but I just don't know if I can justify the much higher cost. After all, here in Sydney's east is not an extreme climate.

B

Posted Saturday 14 May 2011 @ 6:47:30 am from IP #
Catopsilia
Member

Bernardo, the climate of Sydney's east is indeed benign. Perhaps only houses that have unfavourable sites justify double glazing in that area.
The cost of double glazing should be set against estimated savings in the cost of heating and cooling.

Posted Saturday 14 May 2011 @ 12:49:44 pm from IP #
dymonite69
Member

Its possible that your investment may not be paid of in your lifetime if you:

a) live in a mild climate
b) have wide comfort tolerances
c) have a house which is already quite energy efficient
d) use a cheap form of heating
e) buy relatively expensive DG units

Posted Saturday 14 May 2011 @ 2:42:22 pm from IP #
norbert
Member

Bernardo,back to the core of your question. We have used DG PVC windows for the second time (Certain Teed,Eurotech) an as far as I'm concerned I would never use any other material. I also had PVC windows back in Germany which is pretty much standard for most houses(DG is a requirement anyway.)Plastic doesn't shrink or conduct heat or cold, the frame temperature feels nutural Sommer or Winter.They are maintenance free unless you count cleaning the glass as maintenance. Timber might have a more appealing appearence for many but it still slightly shrinks or expand and needs ongoing treatment to stop it from deteriorating.If you go with a white frame it shouldn't discolour, I heard that coloured PVC frames which are now available can start bleaching after years.Regarding cost yes DG PVC windows cost more but I assure you it is money wisely spent and recouped due to reduced heating and cooling cost and quality of living in the house.

Posted Sunday 15 May 2011 @ 2:35:21 am from IP #
Bernardo
Member

Thanks again catopsilia, dymonite. Thanks Norbert.

Norbert, mind if I ask where you live? I wonder what the climate is like. I'm in Randwick, on a hill not far from the sea, exposed to cooling sea breezes and, at this time of the year, the occasional cold southerly, but sheltered from the west.

cheers, Bernard

Posted Monday 16 May 2011 @ 10:09:18 am from IP #
norbert
Member

We live in Woodend Vic which is at the foot of Mt. Macedon 600m above sea level. We do get the occassional snow in winter and below zero temperature. In general summers are also cooler then average Victoria.

Posted Tuesday 17 May 2011 @ 6:01:14 am from IP #
Bernardo
Member

Thanks Norbert.

I'm pasting below some comments from the uPVC supplier I've been talking to. This is his reply to some of the criticisms I've seen:

"uPVC which discolours and becomes brittle has not be treated with “Titanium Dioxide”. Our German suppliers provide uPVC which has “Titanium Dioxide” which prevents UV (Ultra-Violet) rays from damaging the uPVC.

"Our products do not give off fumes.

"Our products are also lead-free.

"I looked on the internet regarding VOC and they typically refer to PVC adhesives. This does not affect our products as they are not adhesives.

"When uPVC profiles for window and door manufacture was initially introduced in Europe, the competing aluminium and timber window manufacturers started to post this sort of misleading information to scare people way from uPVC so when researching uPVC, read many articles and and look for valid source materials and references."

Probably if we were in a more extreme climate, I would spend more time trying to get to the bottom of these issues with uPVC or, if money were not tight, I'd go for Paarhammer. As it is, I think I'll err on the safe side and go with timber single-glazed with various treatments such as low-e glass or Optilam.

Thanks for all your comments, B

Posted Thursday 19 May 2011 @ 10:48:51 pm from IP #
SCADA
Member

Hi Bernardo, I would recomend you go for uPVC. It is just so better. I came from Europe and renting not far from Melbourne. My energy bill is going throgh the roof. At the same time i do this full time funny job with blind close them every night and open every morning. One more things, the heater that turns on and off every 15 minutes, that long takes the temp drops by 2 degrees. and etc and etc just forgot to say you can also cut a bit of noise if you have neibours with dogs or somone who party all he night.

Kommerling is a vey good brand. I totally agree with you.

"Its possible that your investment may not be paid of in your lifetime if you:"
I would agree with your statement.
Here is how i culculate it.
1. uPVC price - Timber or Allum windows single glaze = (price difference)
2. take your annaul elect and gas bill = (with uPVC you can save up to 40%)
3. Every year you elect and gas price will rise let's say 3-5% or more
For eg. my case.
house with 29 sq m of windows (uPVC w doble glaze - qoute about $15000)
standart single glaze allum for the same house roughly $6000-7000
Price difference $8000
Annual gas and elect bill around $4000 if i can safe $2000 (installing uPVC)
My windows will paid of themself in 4 years PLUS i will get a better life style.

Posted Tuesday 24 May 2011 @ 3:28:33 am from IP #
tintac
Member

If you haven't found them yet, and money's tight, get a quote from Ecovue. They import them from China. But make sure you get supply AND install.

I bought them from this mob, and they are pretty good to deal with, but I made the mistake in believing that installation would be pretty straight forward. It isn't and my carpenters did not do the job as quickly as I was led to believe.

They are terrific as we are on a fairly busy road and they made an instant acoustic difference inside those rooms. I'm confident they'll also improve the environment thermally in most cases. In mine not completely, as the uninsulated timber floors and high ceilings have kept the rooms cool so far. When we put in some underfloor insulation things might be better I hope.

As far as discolouring, I'm told that uPVC is chemically stable.

Posted Wednesday 25 May 2011 @ 9:58:07 am from IP #
Anonymous
Unregistered

Hi,thanks for sharing the information here but i've no idea about it....

http://www.xpresshred.com

Posted Wednesday 25 May 2011 @ 10:28:50 am from IP #
mblewett
Member

Hey bernardo,
we live S/E suburbs of Melbourne and we have the Certainteed uPVC windows and we love them. Yes, they are expensive, but they are worth it. had them for about 5 years now. No signs of fading, no off-gassing that I am aware of.
Very, very happy with the finished product. And certainly very happy with not having to maintain and paint them every 5-10 years. If I was to have a complaint it would be that the double-glazed sliding doors are very heavy and hard for my young kids to open and close properly. Certainteed also do a cheaper chinese version (I don't recall the name) which we used for the 'dead' side of the house. Wish I hadn't now, I much prefer the australian-made ones.

- michigan_frog

Posted Friday 27 May 2011 @ 4:01:55 am from IP #
SCADA
Member

If you go for China option make sure that you are buying a good profile sertified to Aus standard. Ask them for a doc test in aus lab.
I had a couple deals with WindowsFactory, quality is very good, they have two options China and Australia made, the difference might be up to 30%. (you can choose youself) But the advantage is they work only with German profile Kommerling.
The best thing to do, ask for a quote everyone and then make a decision.
I will agree with tintac, istall with the same company who made the windows.

Posted Monday 30 May 2011 @ 9:11:03 am from IP #
Eamon
Member

Something not considered as you get cold southerly's is the frame profile. Some upvc companies use single profile frames, the better coompanies will use a profile which has two or more void spaces within the framework.This has the benefit of preventing a cold 'bridging' on your frame. The problems associated with cold bridging are obviously the drop in temp but when condensation arises and sits on the framework, it then stagnates and turns to mould and bacteria grows. You will see this on most single glazed, aluminium frames. E.

Posted Thursday 2 Jun 2011 @ 11:20:55 am from IP #
Bernardo
Member

Many thanks for all the comments.

I'm impressed by Rylock. The windows seem well made. Also chanced upon a sales rep who was knowledgeable. But you pay a lot for composite frames and their performance is inferior to standard timber as far as I can tell.

I'll probably go for standard timber double-glazed. uPVC is certainly cheaper but I find it hard as a layman to assess quality, plus my wife is lobbying for the look of timber.

I've checked out both Trend and Stegbar. I'll probably avoid Trend. The sales rep seemed to know even less than me about thermal efficiency. Found someone more informed at Stegbar and it seems my builder gets a good discount with them.

I'm also told that the build quality of Stegbar is better though I have no way to assess this yet.

Posted Saturday 18 Jun 2011 @ 10:03:43 pm from IP #
suprok
Member

My first post here, great forums been reading them for awhile. Another resource to read about double glazed windows is the windows & doors section on the homeone forums (http://forum.homeone.com.au/viewforum.php?f=23 - hope the link isn't against the rules).

Dynomite69 also posts some great info there. Also look for ed@ecoclassic's posts - he is very informative & his company appears to have some good DG windows (I have no affiliation other than enjoying his posts).

As for PVC frames, I know nothing about widows but my own company fabricates products from uPVC for the electrical/telco civil market. White conduit intended for above & below ground telco use (think phone lines & fibre optic cable) has UV stabilisers added & lasts 20+ years without discolouring or cracking.

Have a look at most wooden power poles in older suburbs - there is usually a white 61mm OD Telstra conduit running up the side of it. Most have been in place for 10-20 years & are still bright white. There is also usualy a 27mm OD white conduit (or 25/32mm if Austel size) conduit running out of the ground on the facade or side of your house - this houses the phone line conntection from the underground pit nearby. The top of that conduit is also exposed to the sun & will stay white & strong.

The only issue we have ever found is if the white UV stabilised conduit has been left out in the scorching summer sun for many months & then we immerse it in our extremely hot glycerine baths (150+ degrees C) it does turn a murky yellow colour.

I don't think you need to worry about the frame yellowing, since I cannot recall too many days over 100 degrees celcius lately

uPVC conduit extruded in Australia does use a lead based stabiliser. In Europe these are banned & they use an organic compund which is more expensive. Australian extruders will not follow suit until legislation forces them to. The amount of lead leeching out though is so minimal it is way below any health concerns; just the EU seems to be overzealous sometimes. Not sure if the profile extruders use organic compunds though.

Interestingly, PVC conduit is banned in many European countries - they generally use polyethylene based pipe products. Known here as poly pipe, bore pipe or continuous pipe - it is certainly gaining market share here, mainly due to ease of boring large continuous runs without having to dig out trenches & solvent glue 4m lengths of PVC together.

For our own custom house we will be specifying double glazed uPVC. Actually, today we went & looked at a display house just for some inspiration (or to remember what not to do, since some of the techniques are so dodgy!) & was amazed that Henley homes have a new Japanese designed house which had aluminium double glazed windows throughout (think they were A&L brand). Never seen that in a project home before.

Posted Sunday 19 Jun 2011 @ 7:34:06 am from IP #
jeffjj
Member

I looked into uPVC frames 2 years ago when planning a home extension. I decided that the Australian made ones were very flimsy looking and not very cheap. The European ones looked better but were very expensive. Actually the 2 most solid looking windows we found were Paarhammer (wood) and Miglas (composite) frames but the price was just too much.
With regard to SCADA's comment about the payback period, I am not sure why, and I may be wrong, but I actually reached the opposite conclusion when I did the figures for my extension; I calculated that double glazed, locally made aluminium framed windows were so much cheaper than the above mentioned brands that the "pay back" period was very very long and not worth considering- much more energy saving "bang for the buck" could be made in other areas eg extra wall/ceiling insulation.

Posted Wednesday 22 Jun 2011 @ 7:35:23 am from IP #
Bernardo
Member

Hi,

One thing that still puzzles me is the minimum air gap for double-glazing. I've seen it stated that 10-12mm is the ideal minimum. One quote I'm looking at offers only a 6mm airgap. Might that be enough, given that I live in temperate Sydney, by the ocean?

Also, for noise reduction, is the answer to go for different thicknesses of glass --- for example 6mm glass facing the street, air gap, then maybe 4mm glass facing into the room?

Thanks again.

B

Posted Sunday 10 Jul 2011 @ 9:28:54 pm from IP #
dymonite69
Member

12mm is optimum.

http://forum.homeone.com.au/viewtopic.php?f=23&t=17758&sid=d4b3185b5e8fbbc0e77bc9c37fd9af8d

Too narrow leads to conductive loss

Too wide leads to convective loss

Err on the side of too wide than too narrow.

Posted Monday 11 Jul 2011 @ 12:42:03 am from IP #
Bernardo
Member

Thanks dymonite,

Practically, I face a choice between aluminium 4/12/4 and timber 4/6/4.

The U values on WERS do not look dramatically different. And I wonder if a 6mm gap would be sufficient here in Sydney's east, where the temperature variation is not great?

Thanks, B

Posted Monday 11 Jul 2011 @ 9:24:30 pm from IP #
dymonite69
Member

WERS uses a standardised window size calculates whole of window U values that take the frame in account. The smaller the window, the more the aluminium U value predominates and vice versa.

Posted Monday 11 Jul 2011 @ 11:33:55 pm from IP #
suprok
Member

Need to correct my previous post so I don't spread wrong info - was talking to our conduit extruders the other day & realised I was thinking about the wrong specs. Standard white comms & Telstra conduit does NOT have a UV stabiliser added since it is mostly buried underground. The conduit up the side of poles will most likely shatter if you hit it hard - will still last many, many years in the sun, but gets very brittle.

DWV pipe (stands for: drain, waste, vent) does have a UV stabiliser added since it is used on the outside of buildings & designed to last in the sun - think rainwater downpipes, sewerage, etc.

Posted Friday 15 Jul 2011 @ 1:27:08 am from IP #
munter
Member

Bernardo said:
And I wonder if a 6mm gap would be sufficient here in Sydney's east, where the temperature variation is not great?

We are using 4/6/4 in our windows in the lower northshore. There was a reasonable cost reduction in going down from 4/10/4 which seemed like fair compensation for the presumably lower performance of the narrower gap. I'll tell you in 5 months when the job is done whether the windows were worth it or not!

Posted Friday 15 Jul 2011 @ 3:32:26 am from IP #
Jeffbloggs
Member

A silly question maybe, but does the height of the DG window affect the amount of convection loses? What is the temperature gradient from top to bottom of a door height window, in comparison to a wide kitchen bench window? Does this temperature difference over the height of the pane, including the difference between the outside and inside pane of glass promote convective loses by inducing airflow between the panes? Does anybody have any information on this? Thx JB

Posted Friday 15 Jul 2011 @ 4:00:31 am from IP #
dymonite69
Member

Anecdotally, I s

Jeffbloggs said:
but does the height of the DG window affect the amount of convection loses?

Height certainly influences the magnitude of the stack effect i.e. downward movement of air. This accelerates the heat transfer through the pane.

Anecdotally, we find this is quite apparent from our 2.4m2 high DG units. You can feel it if you leave a gap at the bottom of the blind. In future I would break the sections into top and bottom halves.

Posted Friday 15 Jul 2011 @ 7:12:59 am from IP #
Jeffbloggs
Member

Thx D69
Roughly how much does it reduce the DG insulation properties? 5-10%? Or more? How much of a stack effect takes place inside the 2 panes of glass? And would it make sense to reduce the DG gap to reduce the stack effect loses ie less air moving between the panes = reduced velocity and mass transferring heat? So basically a wider window is better than a tall one? I suppose that would apply even more so to a single pane glass window.

Another question is how does rain/water affect SG/DG windows. Will water evaporation off the glass effect the thermal performance?

Posted Friday 15 Jul 2011 @ 9:56:22 am from IP #
Peterws
Member

Ecovue....I can't believe that someone would recommend them.
I have recently shelled out $30k for windows from this company and they are hugely disappointing.
they come in many pieces without an inventory or intructions, with numerous parts missing and not fitting, our bifold door (valued at about $5k) does not open properly the hinges can not support the weight the seals have deformed and you can see daylight through the abutments ........seriously with hindsight I would buy a local product or which there are many and you will not need to pay much more.

Ecovue is a second rate product and the customer support is is even worse........my builder is more angry that I am as he spent 3-4 times in labour than what he expect

Posted Friday 15 Jul 2011 @ 10:56:56 am from IP #
Bernardo
Member

Thanks all. Look forward to hearing your results, munter.

My hunch is that the 10-12mm gap is necessary for climates with big variations in temperature and that here in temperate coastal Sydney a 6mm air gap will still give me noticeably better thermal comfort than single glazing.

Another question: what's the best configuration to reduce noise?

I've been told it's just a matter of going for different thickness in the two panes of glass --- eg 4mm glass facing into the room / 6mm air gap / 6mm glass facing the street.

Is that right?

BL

Posted Friday 15 Jul 2011 @ 11:01:55 am from IP #

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