double glazing existing wood windows

Does anyone have experience of this? Our new house has single glazing - you forget how cold it is! But we don't want to put in nasty aluminium if we can avoid it, so looking to see if anyone has upgraded their wooden joinery from single to double glazing.
Cheers[]

Good to see I'm not the only one who hates aluminium joinery with a passion. It seals too tightly and the condensation can't get out.

Isn't it a bit of a contradiction to install double glazing (which limits heat/noise transfer), while extolling the virtues of wooden joinery which typically 'breathes' by way of its lack of such thermal sealing ? :confused:

I fought tooth and nail to get wooden joinery in our new house...and it's double glazed. I too loathe aluminium joinery.

Double glazing wooden joinery is definitely a good quality option.
Things to check in existing joinery include:
Is the wood in good condition? No rot, borer,
Are the frames and sashes straight and tight fighting? Can seals be added without interfering with the movement of the sashes, and with the weather grooves that help keep water out?
Are the sashes deep enough in section to add the thickness of double glazing? The most efficient space between the panes is 10-12mm, but smaller gaps can be used, and the thickness of the panes of glass is determined by the size of the pane, and the wind strength.
Are the frames, sashes and hinges strong enough for more than double the weight of glass?

If you are counting on the draught around window sashes for ventilation, then it is not controlled by the need for ventilation, but by wind speed, so you end up with ventilation when you least want it. Old aluminium and wood windows both have this problem.

Wooden windows for us too. Jean went to a new house all double glazed in beautiful bush and came back saying never do it, she could not hear any of the sounds from outside, Birds etc. We are planning to just have heavy curtains as the tui's here are to good to miss.

shudder on the aluminium...and my major pet hate is replacing double hung window in villas with ali joinery...

Aside from the pros and cons of aluminium joinery, if you are serious about double glazing, then first of all you will need to make sure you have good insulation on all outer walls (ceiling and floor) If you do, no problem. If you do not, then all that condensation you hope to avoid, will condense on the inside of all outer walls/wallpaper, this now being the coldest area of every room.

Based on our research during a recent reclad that included upgrading our upstairs (bedrooms) ali joinery to double glazed units, not all double glazing is created equal.

Firstly for double glazing to perform optimally the gap between the two layers of glass should be at least partially evacuated of air, and preferably purged with nitrogen or a similar inert gas. At the very least the gap must be sealed and moisture free or else mildew will grow inside your window which is impossible to remove.

Secondly the majority of double glazed aluminium joinery available in NZ has no 'thermal break' in the aluminium frames. A thermal break is essentially an insulating (usually plastic) bead that results in the aluminium on the exterior of the joinery being seperated from the interior joinery of the window. Without a thermal break the aluminium will conduct heat from inside to outside resulting in condensation on the interior of the window joinery and a lot of heat loss through the joinery, especially so in heavy framed items such as bi-folds and ranch sliders.

It is apparent that double glazed joinery is relatively new to the NZ market and many manufacturers are struggling to perfect their designs. It pays to ask a few hard questions before committing to such a purchase. A double glazed 'greenhouse' window that we purchased prior to our reclad was replaced (at the original supplier's expense) due to a total c*ck-up being made of its fabrication []

Double glazing has been available in New Zealand for decades, and the issues with poor quality seals on the double glazing units were more prevalent in the 1980s.
The main problems now may be with North Island companies that have not dealt with many customers wanting to pay for double glazing, and are therefore unfamiliar with the techniques and requirements, until this was forced on them and their customers by changes in legislation in the last 5-10 years.

The air cannot be evacuated from standard double glazing, or the glass would bow in under pressure and the two panes touch. (There is a product available that has a vacuum, but it is imported from Japan, and has visible dots where there are plastic separators between the glass, and metal valves on the panes where the air is extracted.)

The air in the gap is either replaced with dry air, or other gases, and a dessicant is often used as part of the jointer between the panes to reduce the risk of mould growth.

A gas used in the gap is often argon, because this is relatively cheap, and is heavier than air and so does not convect to transmit heat as easily as air.

The cheaper aluminium frames do not have thermal breaks between the inside and outside of the frames, but there have been thermally broken aluminium frames available for many years. These are not quite as good as timber frames thermally.

If you are going for thermally broken frames, also consider the material used for the separator between the panes of the double glazed units. Most use (highly conductive:rolleyes:) aluminium, but there are ones available that don't.

Another thing worth considering is a low-e (emittance) coating on the glass within the double glazed units. This reflects some of the heat back into the building, but does not reflect the different frequency of the sun's heat out.

A low-e coating is no use on single glazing, as it is exposed to condensation and scratching.

I have a friend who is a trades-man glazier, who worked for a company that retrofits old villas with double glazing. They don't replace the joinery, they "adjust" it to take the double glazed glass.

My friend did not stay long at this org as he found their methods to be dubious. Basically, if not done well the windows will leak and mould will develop in places it can't be got at. And essentially the whole window will have been trashed.

So yes it is being done in NZ but you have to be very careful about how.

Better to put a thicker grade of glass in (some types are almost as good as double glazing) and then get good quality curtains or blinds.

And as others have said, make sure your ceiling, underfloors and walls all have good quality insulation.

I lived in Tauranga for a year and remember it as being one of the coldest years of my life [][] So I know that despite its great reputation for lovely weather, it can also get bitterly cold and damp.

Went to the home show yesterday. Have a look at www.kristalbond.co.nz
dubbed as the alternative to double glazing. Haven't had a good look at it yet but sounds promising.

Xartep thanks for that, thicker glass idea never thought of that.

The other thing that just struck me as I sit here in sun through window is double glazing will stop this in winter when wind blowing and sun out

We are double glazing our existing widows on the South side of the house only as that is where the worst weather comes from. We are seriously considering also doing the one big window on the West side. The North side will not be done for the reason sod has just mentioned.

sod;383900 wrote: Xartep thanks for that, thicker glass idea never thought of that.

The other thing that just struck me as I sit here in sun through window is double glazing will stop this in winter when wind blowing and sun out

igor;383913 wrote: We are double glazing our existing widows on the South side of the house only as that is where the worst weather comes from. We are seriously considering also doing the one big window on the West side. The North side will not be done for the reason sod has just mentioned.

I'm at a loss to understand what you both think double glazing is going to prevent. Double glazing is still transparent so will allow the sun to shine in and warm your house :confused::confused:

Thicker glass as good as double glazing. Tui's ad there!