Double Glazing 2015: MetroGlass/RetroDG

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timmmay

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#1360201 6-Aug-2015 17:38

I found aluminium joinery companies about the worst sector ever for service and support. Half of them don't even bother doing quotes after visiting you. The PVC companies I found much better.

oxnsox

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#1360203 6-Aug-2015 17:52

I recently made enquiries from 3 companies regarding indicative costs for double glassing, all were in the same ballpark based on the rough description given.

One indicated a good rule-of-thumb to get an idea on cost was that its about $750 per sq/m of glass.

We're looking at including the UV reducing coating (on some windows) to save the degredation of the carpet and furniture, which we'll need to replace after just 10 years. We see this as an addtional benefit to the desired thermal one

gabba

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#1360229 6-Aug-2015 18:56

We are in the process of doing this also. 1960s brick house with 3 bedrooms kitchen and living room with large number of windows, wooden frames.

Experience so far:
We've had three quotes, one from retrodg and two from glaziers. Retrodg came out the most expensive, just. The glazier using the same system as the retrodg guys was about the same, but so far the experience has been better. Prices for standard non argon, non low e ranged from 28k to 33k. To add low e and argon added about another 5k roughly. I suspect prices vary widely depending on the system used, the work done and to a lesser degree the type of double glazing you chose.

Of course the devil is in the details....
1: there are two systems in use. One called a dry installation method and the other called a wet installation method. The manufacturer of the IGU support both methods but recommends the dry method. Essentially the difference between the two is that the wet method uses silicone sealant to hold the IGU in place. The dry method (thermawood) uses a series of mouldings that support airflow and drainage. Personal view is that even though the silicone is neutral cure, after a number of years I'm guessing there is more likelihood of the wet install leaking, which likely means replacement of the IGU. So even though it's expensive the dry method seems better and this is reflected in the warranty lengths for each system.

2: retrodg came out and measured our windows. The quote arrived reasonably quickly but when I checked, they had missed one room. I rang them back about it and the guy was busy. He was going to ring back but I'm still waiting so have given up on that one. One of the other glaziers also missed a window. I emailed them back about it and had an answer within about 30 business minutes. Potential sale saved!

3: it's important to compare apples with apples. One of the glazier will only quote with Argon gas, the others quoted without, and with. The only other option they quoted was the top end low e solution with thermal spacers, whereas the others only gave the low end low e solutions or didn't make it clear which low e option they were offering.

4: I also noticed that there was some variance in the glass thickness used for each window between the quotes. Glass thickness is important as the thicker the glass the smaller the gap. However there is an optimal gap size depending on if you use argon or not. Onviously different glass thickness will affect your cost. Potentially they may also skimp on safety glass if that is required. One quote may say safety glass for one panel only, but another may say for both.

5: we didn't test this one, but someone has told us that it is worthwhile getting a quote from someone out of town if you can. They can be more hungry for the business and therefore price accordingly.

6: retrodg didn't offer to paint the thermawood timber when they had finished. They just said that for the warranty to be valid the new timber had to be painted within one month. It seemed like a convenient out for them if there were issues. For us painting is a job as some of the windows are up quite high which would have meant scaffolding etc. The two glaziers did, presumably because they wanted to get the job. Worth negotiating.

7: finally, retrodg and the glazier that used the thermawood system also installed seals around the window. Retrodg priced these as an extra. One glazier included them in their quote. The second glazier used the standard raven seal you can pick up from mitre 10. When I asked the first glazier about them he said that the system they use is better because it allows you to get a proper seal on the window so that if the window shape changes over time it will still seal. Maybe I'm gullible but it sounded good to me!

Hope all that helps
Cheers

mattwnz

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#1360278 6-Aug-2015 20:54

timmmay: I found aluminium joinery companies about the worst sector ever for service and support. Half of them don't even bother doing quotes after visiting you. The PVC companies I found much better.

I don't think it is very competitive, as there are only a couple of companies that actaully produce the profiles in NZ. That is what one of the companies told me.

KrazyKid

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#1360339 6-Aug-2015 23:16

Not sure how much difference Argon gas makes in the end. Here is comparisons I found for various frames and DG types.
Due to formatting I've only included the timber frame windows - other frames have lower R values
Doesn't seem to add much more compared to the other options
Full article here

Comparison of typical window (frame and glass) R-values (Rwindow)

Single glazing IGU with 4 mm glass and 8 mm air space : R0.19
IGU with 4 mm glass and 12 mm air space IGU with 4 mm glass, R0.34
12 mm air space and low-e pane IGU with 4 mm glass, R0.47
12 mm air space, low-e pane and argon gas fill R0.51

xlinknz

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#1360553 7-Aug-2015 10:19

wasabi2k: We're in Auckland - Aluminium Joinery - house build in the 80s

42 IGUs - 13 Areas -

3 bedrooms
nursery
lounge (most expensive as one wall is windows + ranch slider - $3k on its own)
dining
stairwell
bathroom * 3
laundry
kitchen

Prices are 11,300 ish for cheapest, 13,189 for better (Climaguard), 14,144 for best (Climaguard + Argon)

1. We considered double glazing but payback was like 25+ years, have you done a cost benefit analysis ?

2. Anyone looked at secondary glazing I recall some new systems that were purportedly as good as double glazing and a lot less ?

macuser

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#1360558 7-Aug-2015 10:29

Here is an alternative to double glazing, which is about half the price.

Called Thermafilm and is a film that goes over your windows. I think it comes out at about half the price of Double glazing with 90% of the performance. I've never used it but a guy I know runs the company.

It doesn't have 100% of the benefits of double glazing, since it won't block sound etc but might be effective if you don't want to replace the windows in your house.

http://www.thermafilm.co.nz/

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andrewNZ

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#1360562 7-Aug-2015 10:40

I predict that PVC will be the next leaky building saga.

It is VERY hard to find info on life expectancy of PVC windows, but the best info I could find was about 20 years. That's pretty terrible in my view. The face that none of the companies I found, advertised life expectancy speaks volumes.

Caravans have been imported for quite some time from the UK with PVC moldings all over them, they don't last long here. The moldings go powdery and brittle.

At this point, I wouldn't install then or buy a house that had them installed, and It would take a LOT of impartial evidence to change my mind.

ratsun81

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#1360566 7-Aug-2015 10:50

Ive had a refit done on our 70's house.

Was originally Aluminium joinery. We got it replaced with Upvc from homerit. Standard double glaze without the extra low-e or argon filled.
Aside from underfloor and roof insulation it has to be one of the best upgrades we have done on the house.

Probably the biggest benefit that i have seen is zero condensation, where before it was so bad that the window sills had rotten and were a nice mold factory.

We had quotes for Alu Joinery, both for Thermally broken and non-thermal break.

prices for 10 windows and 1 door.

Upvc 12k (incl install)
Alu 17k (no install)
Alu Thermally broken 28k (no install)

Wood wasnt really an option for us as i didnt want to have to deal with the maintenance involved.

Dont go for non-thermally broken Alu you will regret it... ive seen how terrible it is for condensation, and it really is one of the best heat transfers around

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timmmay

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#1360591 7-Aug-2015 11:04

I'm not sure caravans are a reasonable comparison - vehicles tend to be replaced regularly so why would you use the best quality materials? It is something to look into though.

From Thermalframe FAQ. Check their testimonials too.

Does Thermalframe PVCu profile stand up to New Zealand UV levels?

The polymer industry world wide has been developed to an extremely sophisticated level. Plastics are now widely used in such applications as the NASA Space Crafts. The science of the industry has advanced to the point where the plastics available to the building industry are of incredible strength and durability. Like all products in all industries, the quality may vary with the integrity of the manufacturer. Thermalframe is second to none when it comes to quality allowing absolute confidence in the stability of the PVCu composition and colour. With the right levels of titanium dioxide added to the PVCu polymer as a UV inhibitor, the Thermalframe suite of windows and doors are currently installed in locations where the uV is much higher than the New Zealand - levels of 100-130Kcal/cm2/yr e.g. Arizona Desert, West Indies. Little degradation has occurred over 30 years and accelerated weather testing confirms longevity.

There's also this. I think 20-30 years is what most people should expect from uPVC.

lissie

495 posts

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#1361173 8-Aug-2015 15:11

timmmay: I'm not sure caravans are a reasonable comparison - vehicles tend to be replaced regularly so why would you use the best quality materials? It is something to look into though.

From Thermalframe FAQ. Check their testimonials too.

Does Thermalframe PVCu profile stand up to New Zealand UV levels? The polymer industry world wide has been developed to an extremely sophisticated level. Plastics are now widely used in such applications as the NASA Space Crafts. The science of the industry has advanced to the point where the plastics available to the building industry are of incredible strength and durability. Like all products in all industries, the quality may vary with the integrity of the manufacturer. Thermalframe is second to none when it comes to quality allowing absolute confidence in the stability of the PVCu composition and colour. With the right levels of titanium dioxide added to the PVCu polymer as a UV inhibitor, the Thermalframe suite of windows and doors are currently installed in locations where the uV is much higher than the New Zealand - levels of 100-130Kcal/cm2/yr e.g. Arizona Desert, West Indies. Little degradation has occurred over 30 years and accelerated weather testing confirms longevity.
There's also this. I think 20-30 years is what most people should expect from uPVC.

This -also I have Thermaframe on order (they are 2 month backlogged at present) - to replace the 29 year old original Aluminum in hte house - the anodised Al is completed corroded on the corners.

Even the Al companies I spoke to wondered about the durabiltiy of power-coasting in the extreme coastal D zone that we are located in

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