[thezorbster]

Has anyone had retro fit double glazing fitted to a house with timber window frames? Just wondered how efficient you found it. We have loads of windows and have just had a surprisingly reasonable quote to do the whole house. We will be asking to see examples of homes they've done it on but wondered if anyone had personal experience. We really don't want aluminium frames as we feel that will destroy the character of the house.
Thanks

[holland]

Hi, Hubby a glazier I will ask him when he wakes up!!!!

J x

[Asli&Mark]

With my my work I have seen a few versions.

One is to take out your glass and fit a sealed unit (double glazing) in it's place, its good because it keeps the stlye of your house easily. The only down fall is the weight, as you have twice as much glass, some frames cannot cope, and sash windows can close of thier own accord. But the person selling it to you, will be able to advise if it is suitable for your frames.

Another I have seen, only once, was new units, wood on the inside, and aluminium on the out side, seamed well made wasn't told a price, but can guess they are not going to be the cheapest.

Hope that helps.
Mark

[Super_BQ]

Although i'm not an advocate of taking an old home and making it more energy efficient, I do believe changing the windows and doors can make a remarkable difference. However, we need to clear up some terminology.

What is exactly "Double Glazing"? Is it just 2 pane windows with an air gap in between?

The reason I ask is because in N. America, windows come in all sorts of specifcations regardless of how many panes (single, double, & triple). Are you looking at "Low E" windows with argo gas filled in between the panes in a sealed unit? Are we talking about the glass that has a Low cut UV coating? Actually, I would not believe low UV cut windows would be popular in NZ as many homes rely so much on "passive" heating (getting heat from the sunshine), whereas in climates like in Canada, houses depend on limiting the amount of energy being TRANSFERRED from inside to outside of the house (regardless of which way the house is facing just to grab passive heating).

What can be worse than aluminum framed windows for energy efficiency? Copper framed? There is nothing wrong with wood framed windows (it's biggest drawback being the maintenance of painting). Actually I don't think there's much benefit changing the glass in an aluminum framed window for double pane.

BQ

[JandM]

In the UK, double glazing implies fitting a sealed unit with a layer of air trapped between the two panes of glass. I've not heard of using another gas, or any particular kind of glass. The intention is to improve insulation, which being the case, UPVC or wood frames are to be preferred to aluminium (although there's some improvement, even with that). The standard double glazed fitments are said to reduce heat-loss by 50%, and therefore cut down energy consumption, especially installed in conjunction with other insulation measures in the walls and roof. http://www.energysavingtrust.org.uk/home_improvements/home_insulation_glazing/glazing
There are also advantages in sound insulation and security.

[renew]

hi,
Alluminium window frames have moved a long way, at least in the UK. Older frames would have been solid allumium which is not ideal particularly in terms of condensation. Newer frames have a thermal break - basically the inside and outside parts are seperated by a insulting material. In the UK you now have to install low-e glass which improves the energy performance.
One issue that has been an issue with double glased units in wooden frames is condensation leading to premature failure of the double glazed unit. Currently they are required to be installed with drainage ( or basically a slot to the outside at the bottom of the wooden unit)

cheers

Ian

[Hackswell]

Y'all don't use vinyl double-paned windows? =blink= Aluminum lets the cold right in where I live in Ohio, USA! =brrrrr!=

[JandM]

I think your vinyl is the same as our UPVC, probably, as the last bit stands for poly-vinyl-chloride. (MUCH used in the UK.)

[thezorbster]

With my my work I have seen a few versions.

One is to take out your glass and fit a sealed unit (double glazing) in it's place, its good because it keeps the stlye of your house easily. The only down fall is the weight, as you have twice as much glass, some frames cannot cope, and sash windows can close of thier own accord. But the person selling it to you, will be able to advise if it is suitable for your frames.

Another I have seen, only once, was new units, wood on the inside, and aluminium on the out side, seamed well made wasn't told a price, but can guess they are not going to be the cheapest.

Hope that helps.
Mark

Thanks Mark
Option 1 was the one we were quoted for. They remove existing glass from the wood frames & insert 2 panes with a gap which can be argon filled if we want. Hadn't thought about the extra weight issue, we don't have any sash windows but have some openers that this might effect so will ask them about this. Do you know if the examples you've seen have had any problems with condensation?
Cheers

[holland]

Hi,

Hubby says they would probably have to be a stepped unit, unless you have got ultra wide frames...which is unlikely. To get any real benefit you would need at least a 14mm spacer plus 2 x 4mm glass, which equals a 22mm unit...which wouldnt fit in the timber frame. Hubby says anything less than this may be a waste of time, although you would get slightly better heat insulation and better sound insulation. You have to bear in mind, the latest UK specs are 32mm units with K-glass which reflects heat back into the rooml, which you won't get over here in a standard unit.

You would get some benefits...you'd be better buying pink bats ( rock wool)..I think this would be more beneficial.

[thezorbster]

Thanks for info Jade - very useful.

Re your suggestion about pink batts - see my separate post about our airfoam experience yesterday!!!!:laugh

[Super_BQ]

They remove existing glass from the wood frames & insert 2 panes with a gap which can be argon filled if we want.

I would be curious on how they can effectively seal the 2 glass panes so the argon gas can not escape? (effectively to fit for your window frames?) As far as I know, these windows are sealed and gas vacuumed at the factory. Quite common for even fully sealed units to have the argon gas leak out over a decade.

IMO, I don't think such Low E argon gas filled windows would be suitable for NZ homes because of the difference in home designs. NZ homes typically are built for the 'passive' heating, meaning that houses with lots of windows that face the sun side are done to capture that free heat.

An energy efficient home is not one that can capture passive heat from the sun. It is one that can limit the amount of energy TRANSFERRED between the inside of the house and the outside (regardless what time of the day or night or how much sun). As long as you apply this building concept, then it makes logical sense to use the low E argon filled windows. You get the best of both worlds with this concept. During the hot summer, the inside temperature of the room would be easier to cool as ie your air conditioner/heat pump is not competing with the heat from the sun light. Likewise in the cold winters, the heater isn't competing with the coldness outside trying to suck all the heat through the window.

Lately the TV has been heavy on advertising insulation. But they miss a crucial fact that NZ homes were never built for high energy efficiency. For starters the house has to be AIR TIGHT. Adding insulation to a wall would have minimal effects if the windows & doors have air gaps. Then there's the issue of the open roof cavity designs where the winds can freely blow cold air through the roof tiles, thus robbing all the heat away (yes hot air rises).

I'm also a sceptic about the HRV recirculating system as an install for older homes. Really, how much heat in the atic space during the winter months (a time where you really need heat the most). Same argument with heat pumps, a small unit really can't get much heat with it's well below 0 - at least not enough heat to maintain an indoor room temperature of 20°C (we could be talking a 30 degree temperature change which is pretty hard to do with only a 3kW mains supply).

BQ