Double or Triple glazing

Coburger

I have had quotes over the past week for windows to be replaced in my house. One company proposes to put in double glazing, the other triple glazing. Both types have a U value of 1 but there is quite a large price difference (triple glazing is twice as expensive).

Does anyone have any experience of double or triple glazing? Does triple glazing make that much of a difference - this confuses me if both companies are advertising their product to have the same U value. Thanks.

Coburg

massy086

Coburger wrote: »

I have had quotes over the past week for windows to be replaced in my house. One company proposes to put in double glazing, the other triple glazing. Both types have a U value of 1 but there is quite a large price difference (triple glazing is twice as expensive).

Does anyone have any experience of double or triple glazing? Does triple glazing make that much of a difference - this confuses me if both companies are advertising their product to have the same U value. Thanks.

Coburg

are both a rated glass

Dudda

Also check if it’s the u-value for the glass they’re providing or the u-value for the window. Some sales people give the u-value of the glass which is better than the u-value of the window. I’m not saying the double glazed person is doing this but they could be to try and show you a better u-value.

mrsWhippy

Are you saying the U-value you were given for both double and triple glazed was 1?

That's either really really bad triple, or really really good double. Something doesn't sound right there! Otherwise what's the point in forking out double the money ...

Anyway, in general, you should be able to get u-values around 0-6 - 0.8 ish, then triple all the way.

T-Maxx

The price difference should only be around 15%. Double is good enough in normal circumstances, triple typically only for sound insulation.

BryanF

T-Maxx wrote: »

. Double is good enough in normal circumstances, triple typically only for sound insulation.

Care to elaborate?

LadyBetty

We started building recently and have been debating about double versus triple glazed windows. Builder pushing for double glazed to keep costs down but I am willing to spend more if triple glazed will make the house more comfortable all year round.

One of my concerns is that we have so much glazing on the south facing side that on a sunny day, winter or summer, it could get way too hot. Is it true that triple glaze will help keep out some of that heat, so we don't bake in the house?

Builder scoffed when I told him this. The BER expert originally told me this but then he put double glazed down on his assessment to keep the costs down.

It might sound like a silly concern to have in Ireland but it is genuinely bothering me.

mike_2009

Triple Glazing will reduce overheating as they let in less light and heat through but you should have other methods designed in to deal with the overheating issue (blinds, external shading, opening windows etc). Shop around to make sure you're getting the best quotes for Triple Glazing. If you have a LOT of south facing glazing, well, it's going to cost...no doubt about it.

By the way, you can get film you add to the glazing afterwards from companies like 3M that might help if you go with double glazing and it's getting too hot. The film works hardest when the sun is at it's highest and let's in more heat when it's lower. I don't know anyone using it or if it's available in Ireland but it may be an option...ideally see what the manufacturer can provide and if adding 3M later would affect warranty etc?
https://www.3m.com/3M/en_US/home-window-solutions-us/

Suggested article: Window Shopping - latest self build Ireland magazine pages 66-69.
https://issuu.com/selfbuildireland/docs/winter_2017

BryanF

mike_2009 wrote: »

Triple Glazing will reduce overheating as they let in less light and heat through but you should have other methods designed in to deal with the overheating issue (blinds, external shading, opening windows etc). Shop around to make sure you're getting the best quotes for Triple Glazing. If you have a LOT of south facing glazing, well, it's going to cost...no doubt about it.

By the way, you can get film you add to the glazing afterwards from companies like 3M that might help if you go with double glazing and it's getting too hot. The film works hardest when the sun is at it's highest and let's in more heat when it's lower. I don't know anyone using it or if it's available in Ireland but it may be an option...ideally see what the manufacturer can provide and if adding 3M later would affect warranty etc?
https://www.3m.com/3M/en_US/home-window-solutions-us/

Suggested article: Window Shopping - latest self build Ireland magazine pages 66-69.
https://issuu.com/selfbuildireland/docs/winter_2017

Triple can reduce solar gain by as little as 10% over double. But in the evening when your trying to keep the heat in triple will be better.

Careful with glass films. The glazing manufacture would want to sign off on this .

LadyBetty

That's the other side of it; it's a fairly windy exposed site so with all that glazing I wonder will it feel cold / draughty on stormy winter nights if we get double glaze.

Builder's quote is for Munster Joinery double glazed. He reckons they are the best value.

Thanks for replies, plenty to think about. Never heard of that film before, interesting point.

g1983d

You can also do a mixture by having triple on North facing and double on south facing.
I got triple glazing from -snip- when building 2 years ago and I'm delighted with them uvalue is 0.7 as far as I remember

BryanF

g1983d wrote: »

You can also do a mixture by having triple on North facing and double on south facing.

Why would anyone do this. It makes zero sense

dubrov

BryanF wrote:

Why would anyone do this. It makes zero sense

Because it is sunnier on the south side so you might be happy to allow more heat to get out as long as more heat can get in

g1983d

BryanF wrote: »

Why would anyone do this. It makes zero sense

If you'd like triple glazed for better uvalue or sound proofing, but can't stretch to the cost for the whole house.
Then put it where you'd get most value from it

BryanF

dubrov wrote: »

Because it is sunnier on the south side so you might be happy to allow more heat to get out as long as more heat can get in

Rubbish
It’s the opposite.

g1983d

BryanF wrote: »

Rubbish
It’s the opposite.

If it's the opposite then put the triple on the south side and double on the north side :-)

It was only an idea and surely some triple glazing is better than none

chicorytip

LadyBetty wrote:

That's the other side of it; it's a fairly windy exposed site so with all that glazing I wonder will it feel cold / draughty on stormy winter nights if we get double glaze.

Triple glaze is effective at blocking out traffic /road noise so if your house is situated in a busy urban location it would be of benefit but otherwise the extra expense would not be justified.

Metric Tensor

Be careful not to mix up "best value" and "cheapest" - they are two completely different things!

dubrov

BryanF wrote:

Rubbish It’s the opposite.

For a moderator your posting style is pretty abrasive.

You may be right but could you at least detail what part is rubbish and why?

fatty pang

massy086 wrote: »

are both a rated glass

What's 'a rated glass' ?

fatty pang

LadyBetty wrote: »

Builder scoffed when I told him this. The BER expert originally told me this but then he put double glazed down on his assessment to keep the costs down.

It might sound like a silly concern to have in Ireland but it is genuinely bothering me.

I wouldn’t expect a builder to know much about it and the quality of BER assessors is a very mixed bag, as is DEAP.

Article in today’s Sunday Times about a flagship refurb in Dublin shows how even the expensively acquired ‘experts’ can make a balls of it.

https://www.thetimes.co.uk/article/go-ahead-council-transforms-unrentable-block-ofbedsits-into-energy-efficient-apartments-b7rg2lrbb?shareToken=1904929876cb3e57a582c5e7b1806d1f

“There is a downside, however, and that’s overheating. “In summer, we have had great difficulties with heat. On one day in May, we had 27.3C inside our apartment, and it was uncomfortably hot on quite a few days in summer.”
There is no shading or other features to mitigate this problem, so Falconer has installed Venetian blinds and bought fans for bedroom and living room areas.
The opening sections of the windows are quite small, and because his apartment faces away from prevailing winds, it is difficult to introduce any natural air movement into the living room or bedroom.
The passive house software does evaluate overheating risk. In order to meet EnerPHit criteria, the internal air temperature should not climb above 25C any more than 10% of the time during the year. In Rochestown House, the analysis concluded that there was zero risk of overheating, that the temperature would not move above 25C at any time.”

I’m sure the consultants involved will no doubt be compensating the client for the cost of rectifying the problem.;)

fatty pang

mike_2009 wrote: »

Suggested article: Window Shopping - latest self build Ireland magazine pages 66-69.
https://issuu.com/selfbuildireland/docs/winter_2017

That article is riddled with errors.

fatty pang

chicorytip wrote: »

Triple glaze is effective at blocking out traffic /road noise so if your house is situated in a busy urban location it would be of benefit but otherwise the extra expense would not be justified.

Standard triple-glazing makes no discernible difference to sound attenuation when compared with standard double glazing when it comes to traffic noise. Look up the data from the glass manufacturers rather then relying on hearsay.
The extra expense (circa 10-15%) can be justified by a typical reduction in heat loss of 30-40% when compared to typical double-glazing and improved occupant comfort when sitting close to windows when its cold outside.

fatty pang

Metric Tensor wrote: »

Be careful not to mix up "best value" and "cheapest" - they are two completely different things!

Prominent refurbishment project in Dublin did just that recently. Change in window supplier mid-project. A Q/S will often give as much thought to choosing windows as they will to choosing toilet paper.

fatty pang

dubrov wrote: »

You may be right but could you at least detail what part is rubbish and why?

It’s not a case of he ‘may’ be right. It‘s basic building physics. Everybody is entitled to an opinion but you’re not entitled to have it taken seriously.

chicorytip

fatty pang wrote:

Standard triple-glazing makes no discernible difference to sound attenuation when compared with standard double glazing when it comes to traffic noise. Look up the data from the glass manufacturers rather then relying on hearsay. The extra expense (circa 10-15%) can be justified by a typical reduction in heat loss of 30-40% when compared to typical double-glazing and improved occupant comfort when sitting close to windows when its cold outside.

No, I am not relying on hearsay but am speaking from direct experience. I happen to live on a busy road with heavy traffic and have recently installed triple glazed front windows. The reduction in noise from outside is very significant.

Gumbo

chicorytip wrote: »

No, I am not relying on hearsay but am speaking from direct experience. I happen to live on a busy road with heavy traffic and have recently installed triple glazed front windows. The reduction in noise from outside is very significant.

How old are were the windows you took out?

chicorytip

kceire wrote:

How old are were the windows you took out?

Fifteen years old - double glazed.

fatty pang

chicorytip wrote: »

Fifteen years old - double glazed.

If the new window that was installed had standard double-glazing there would be a difference of 1dB between that and standard triple-glazing. It’s to small of a difference for the human ear to notice.
The new window will likely have replaced an old window that had old seals of limited effectiveness. Its probable that the installers will have used a foam sealant around the perimeter which will also help with attenuation.
You will get a significant reduction in sound transmission from putting in a new window even if it was single-glazed when compared with an old double-glazed window that has missing or well worn gaskets.
in saying that you did the right thing by putting in triple-glazing for heat retention.

Lumen

Do window vents let noise through?

I'm planning to upgrade from 1980s wooden framed single glazing but still want to hear the birds sing when I wake up.

dubrov

fatty pang wrote: »

It’s not a case of he ‘may’ be right. It‘s basic building physics. Everybody is entitled to an opinion but you’re not entitled to have it taken seriously.

Maybe you would like to share your wisdom then. What part was rubbish and why?

fatty pang

dubrov wrote: »

Maybe you would like to share your wisdom then. What part was rubbish and why?

The inference that a window in this climate will gain more heat then it loses.

fatty pang

Lumen wrote: »

Do window vents let noise through?

Not half do they. Some manufacturers will have tested windows with trickle vents in the open and closed positions and should be able to give you an indication of what to expect.

dubrov

fatty pang wrote: »

The inference that a window in this climate will gain more heat then it loses.

Ok. Thanks for clarifying.
I don't see how that was inferred though.

It wasn't what I meant anyway

Dudda

fatty pang wrote: »

dubrov wrote: »

Maybe you would like to share your wisdom then. What part was rubbish and why?

The inference that a window in this climate will gain more heat then it loses.

Not true and this is how passive houses are designed. If you look at the PHPP calculations below in the highlighted right hand column you'll see the numbers with a positive value are all the windows in my house which gain more heat than they loose over a year. Yes the house overheats a small bit in summer.
The PHPP takes into account climate (in my case Belmullet in north Mayo), shading, exposure of the site, orientation, frame thickness, g-value, etc.

Now my windows are high quality triple glazed passive house certified windows. The ones BryanF referred to as rubbish on page one of this thread were double glazed in which case you won't get more heat in than you loose over the year so he's correct in the saying the statement was rubbish but could have clarified this.

Windows vary widely in quality and performance so it's not the case that all triple glazed windows will provide more heat through thermal gain than they loose. It would also more depend on other aspects like frame to glazing ratio, orientation, shading, etc.

Personally with windows I'd always spend as much as you can. It's not something you can or will change easily later. You'll replace the kitchen, refurbish a bathroom, replace a floor covering, etc long before you replace windows.
As per my first post (3rd in this thread) I'd question the sales guy on the u-value of the double glazed windows. It doesn't sound right.

fatty pang

Dudda wrote: »

Not true and this is how passive houses are designed.

You’re correct. A very small proportion of windows installed here, suitably sized and orientated, dependent upon the fabric, form & internal layout of the building, with adequate winter sunshine may provide a useful net heat gain during the heating season – no point in having it in summer. As you point out some of the windows in a Passive House will meet these criteria. I will have to mind my language.

MartinHD

I've recently had a salesman in quoting me for replacement of older double-glazed units by the 'new' low-e glass ones in an add-on conservatory which has teak window frames in fine condition. He told me that all my existing units had lost all their argon gas, which he said explained why the room was so cold! He did this by holding a small hand-held device up to the glass (on the inside) and it glowed red or not depending on (he said) the presence of argon gas inside the glazed unit. I was a bit sceptical I have to say.

Does anyone know if it is so simple to actually detect argon gas inside a sealed double-glazed unit?

Pat.

BryanF

MartinHD wrote: »

I've recently had a salesman in quoting me for replacement of older double-glazed units by the 'new' low-e glass ones in an add-on conservatory which has teak window frames in fine condition. He told me that all my existing units had lost all their argon gas, which he said explained why the room was so cold! He did this by holding a small hand-held device up to the glass (on the inside) and it glowed red or not depending on (he said) the presence of argon gas inside the glazed unit. I was a bit sceptical I have to say.

Does anyone know if it is so simple to actually detect argon gas inside a sealed double-glazed unit?

Pat.

Ignoring the sales pitch - how old are the windows?
And are you trying to take the ‘conservatory’ and turn it into a room as opposed to a sun room?
Argon dissipating is not the reason it’s cold - the reason it’s cold is it’s a conservatory


Pat I closed the other thread, can you stick to 1 topic / 1 threadin future. Thanks https://www.boards.ie/vbulletin/showthread.php?t=2057797491