# Should I buy triple pane windows?



## Unicornz0 (May 22, 2012)

I’m in Michigan & planning on buying Wallside Windows insulated replacement windows.
The Salesman has advised against buying triple pane windows.
The increased cost to me is 25%.
One Salesman said the R rating for their double hung is 4, &
4.2 for the triple pane. 

Their specifications are not anywhere in their brochures, &
I forgot to snap a picture of the energy efficiency sticker on the window pane.
That’s probably just for the glass anyway. 

I’ve received conflicting information from the Company.
The Salesman says the triple pane will provide some extra sound deadening, but not much in the way of energy efficiency heat/loss.
A different Salesman said, anyone saying triple pane insulate more than double panes against sound is mistaken (Sales professionals, gotta love ‘em).

It seems like a no brainer to me to buy the triple pane windows instead of the double pane windows, despite the info from the Salesmen.
Heating & cooling costs will continue to rise.
I’m thinking the profit margin must be less on the triple pane windows.

What do you think?

Thanks,
Uni


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## joecaption (Nov 30, 2011)

I think you need to go back and add your location to your profile for a better ansewer.
Just go to Quick links to edit.
I know in my area I've never seen anyone buy triple pane windows.


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## Unicornz0 (May 22, 2012)

joecaption said:


> I think you need to go back and add your location to your profile for a better ansewer.
> Just go to Quick links to edit.
> I know in my area I've never seen anyone buy triple pane windows.


Thanks Joe,

The subject house is in Michigan.


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## sixeightten (Feb 10, 2009)

Triple pane windows are not much more efficient than double pane. We do a lot of high end homes, and have only used triple pane a couple of times. It is for those who just have plenty of money, and want to go the extra mile on everything. I am sure the commission is why the salesman is pushing them.


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## Unicornz0 (May 22, 2012)

sixeightten said:


> Triple pane windows are not much more efficient than double pane. We do a lot of high end homes, and have only used triple pane a couple of times. It is for those who just have plenty of money, and want to go the extra mile on everything. I am sure the commission is why the salesman is pushing them.


Thanks,

But the case is just the opposite. I think the Salesman doesn't want me to purchase the "triples" because his commission will be lower.


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## sixeightten (Feb 10, 2009)

Unicornz0 said:


> Thanks,
> 
> But the case is just the opposite. I think the Salesman doesn't want me to purchase the "triples" because his commission will be lower.


Sounds like reverse psychology. I think he wants you to think that.
One piece of glass adds how much to the total price of each window? :laughing:


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## concretemasonry (Oct 10, 2006)

That is the fault of the salesman and the supplier he works for. As I recall, the "R" value is based on heat transmission (hot box test) and does nor really represent average radiant heat loss that can be very high in the winter (cold and dark), so sheet hung over the opening would be many times better and extra panes a funny/exotic gasses.

You could be better to fill the "hole in the wall" with uninsulated concrete block from energy standpoint, since they are always better that glass when it comes to radiant heat loss in the cold MI winters. - A little extreme, but I hope that puts things in perspective since a 3 pane is minimally better for insulation that a good pane day and night or summer to winter.

Dick


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## 747 (Feb 11, 2005)

Triple pane would help with sound. For energy efficiency. low e argon filled is pretty much the best.


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## HomeSealed (Jan 3, 2008)

Triple pane glass has very little effect on sound. Here are some bits and pieces from Oberon (please let me know if I take anything out of context):
_"When considering window glass performance there are three primary products to take into account for maximum possible sound attenuation. 

"First is laminated glass. 

Second is a wider airspace between the lites. 

Third is different thickness lites within the IGU or Insulating Glass Unit. 

Fourth would be a combination of all three. 


Airport windows, as an example, generally have laminated glass on both sides of an IGU in an aluminum frame and with a maximum airspace between the lites. In an airport the primary concern is sound attenuation and energy efficiency is secondary. I mention this because the width of the airspace and the choice of window framing material affects both sound and energy efficiency. 


Some folks will suggest triple pane glass for its sound deadening ability, and while triple pane may be a slight improvement over standard double pane at lower frequencies due to the additional density of the extra lite, overall there is no difference in STC rating between triple and double pane provided that the overall airspace between the panes is constant between the two constructions. 


In other words, a triple pane with two 1/4" airspaces and a dual pane with a 1/2" airspace – both using 1/8" glass – will have the same STC assuming that windows are otherwise the same...
...So why do folks with new dual pane windows, after living with single pane, often comment that the improvement in blocking unwanted outside noise? Often, this is due to the replacement window being tighter than the previous older window, but also the addition of the airspace between the lites of a dual pane – rather than to the effect of the additional lite, unless as mentioned the lites are different thicknesses – can have an effect on sound propagation. So in that sense, the additional lite in a dual pane window improves performance over a single pane by the formation of the airspace. 

But this doesn’t always apply when adding triple pane due to the decrease in the airspace between the lites overriding the potential advantage of the additional lite._

Regarding energy efficiency, triple pane is undoubtedly more efficient than double pane. The question becomes by how much, and at what added cost. In a cold climate like yours, it certainly would not be unwise provided that the price is right. At 25%, that sounds about right if you are talking product only (not installed).
I'd also add that the U-value, while the primary indicator of thermal performance, is not the only thing to look at. The SHGC rating will tell you how much passive solar gain is allowed to pass through the unit, and you want that to be higher (.25+) in your climate. You can even customize it based on the direction each window faces (higher gain on south wall), landscaping, etc, although the impact of that becomes slightly less important for most urban homes surrounded by neighbors, trees, etc. 
You will also want to pay attention to the structural ratings of the unit, primarily air infiltration. A window that leaks more air will be less efficient, and have a measurable difference in sound transmission as well (certainly more than double vs triple pane glass). The best performing products on the market are achieving AI ratings as low as .o1cfm. Baseline is .30cfm, so you can see a pretty substantial difference.


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## RWolff (Jan 27, 2013)

I dont feel triple is worth the extra cost not for 0.2 more R value over double pane, it's miniscule


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## oberon (Apr 29, 2006)

Unicornz0 said:


> I’m in Michigan & planning on buying Wallside Windows insulated replacement windows.
> The Salesman has advised against buying triple pane windows.
> The increased cost to me is 25%.
> One Salesman said the R rating for their double hung is 4, &
> ...


Very odd, I think.

A whole window R-value of 4.0 (U-.25) is very good for a dual pane window, but a whole window R-value 0f 4.2 (U-.24) is not very good for a triple pane window.

I am not sure the salesman is giving you an apples to apples comparison.

According to their website, Wallside windows uses one of the Climagard RLE Low-E coatings from Guardian and PPG's Intercept spacer in their window systems. 

Taking that into account, and not saying for certain, but I suspect that the salesman was passing "center-of-glass" values for the dual pane rather than whole window performance numbers when he quoted the R-4 based on the values that you were given.

A dual pane IGU using Guardian's Climaguard 70/36 RLE applied to surface 2 and with a 90% argon-fill airspace will result in a center-of-glass U-.25...I suspect this isn't a coincidence.

I am at a loss where the salesman came up with an R-4.2 for the triple though - assuming he was only passing glass-only numbers. 

A three pane, 3mm glass, IGU with 1/2" airspace but without LowE-coating or argon fill is going to top out (center-of-glass) about R-3.2. 

Adding 90% argon to both airspaces isn't enough to get to R-4.2, and adding the Low-E coating to just one lite is going to exceed the R-4.2 that he quoted you. 

Possibly he did quote whole window performance for the triple, but once again, R-4.2 for whole window triple really isn't that good.

Just for comparison, the glass-only performance of a triple with the Climagard RLE coating on two glass surfaces (either 2 & 4 or 2 & 5), as well as 90% argon fill to both airspaces is going to achieve center-of-glass performance of R-8.25 (U-.12).

Total window performance will be less than center-of-glass number's because the best insulating portion of any window is the center-of-glass, by definition the entire glass surface that isn't within 2 1/2" of the edge of the glass. 

As a side thought, when I hear about window salesperson's quoting R value rather than U value for window performance numbers, I immediately wonder if he/she is actually quoting center-of-glass...but I know that some salespeople do quote R value for full window performance because consumers are more attuned to R than to U. 

So a question for window salesfolks reading this, do you prefer R value or U value when quoting potential customers, and why?


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## Unicornz0 (May 22, 2012)

oberon said:


> Very odd, I think.
> 
> A whole window R-value of 4.0 (U-.25) is very good for a dual pane window, but a whole window R-value 0f 4.2 (U-.24) is not very good for a triple pane window.
> 
> ...


Thanks Oberon,

The salespeople are trying to steer me toward their double pane window.
I get the feeling 1 of the salesmen is not being honest with me.
I have had their windows installed at another residence & am pleased with their service. I really can't speak to the performance of their windows.
I'm trying to be an informed Consumer & make the best choice. I now have more relevant questions for the Salesman.

Thanks again Oberon for your research & explanation.
Uni


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## HomeSealed (Jan 3, 2008)

oberon said:


> So a question for window salesfolks reading this, do you prefer R value or U value when quoting potential customers, and why?


I find cog U values to offer little value in terms of educating consumers on a window purchase, and R-values to have very limited benefit -- primarily used only to explain what U-value means and put things in perspective, as R-value is more familiar to most folks. Total unit u-value is the most effective measure IMO. It is the number that is most readily available (on NFRC.org), comes printed on the NFRC sticker affixed to every window, and actually gives the most accurate and comprehensive portrayal of how the window unit will perform. In my experience, cog values and R-values are used most often by unscrupulous salespeople to manipulate and mislead homeowners. Not to say that is the case here, but this situation certainly is a good example of why it is best to stick to one common rating when comparing. 
I didn't look at the rating details at first, but I would agree that something appears off. A window that gets a .25 total unit u value in double pane (low-e argon) should see a drop in the ballpark of .05 (give or take) by upgrading to triple pane (low-e argon).


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## Unicornz0 (May 22, 2012)

HomeSealed said:


> I find cog U values to offer little value in terms of educating consumers on a window purchase, and R-values to have very limited benefit -- primarily used only to explain what U-value means and put things in perspective, as R-value is more familiar to most folks. Total unit u-value is the most effective measure IMO. It is the number that is most readily available (on NFRC.org), comes printed on the NFRC sticker affixed to every window, and actually gives the most accurate and comprehensive portrayal of how the window unit will perform. In my experience, cog values and R-values are used most often by unscrupulous salespeople to manipulate and mislead homeowners. Not to say that is the case here, but this situation certainly is a good example of why it is best to stick to one common rating when comparing.
> I didn't look at the rating details at first, but I would agree that something appears off. A window that gets a .25 total unit u value in double pane (low-e argon) should see a drop in the ballpark of .05 (give or take) by upgrading to triple pane (low-e argon).


Thanks Again.

Is the "Total unit u-value" the "U" value on the glass pane?
I want to ensure I'm reading the "Total unit u-value".


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## HomeSealed (Jan 3, 2008)

The total unit u value tests the complete window unit, fully assembled (glass, frame, weatherstripping, etc)


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## Unicornz0 (May 22, 2012)

HomeSealed said:


> The total unit u value tests the complete window unit, fully assembled (glass, frame, weatherstripping, etc)


Will it be listed on the window as the "U" value or the "total unit u value"?

Thanks Again,
Uni


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## concretemasonry (Oct 10, 2006)

Just try to find a documented and universally accepted "U" value for window assembly.

A wall with R19 insulation can have an actual R9, just as a comparison with the real world. The "Pink Panther" does not like it or dispute it, since the test is a universally accepted laboratory testing industry (costly and realistic).

Actual product assemblies depend on all materials and cannot the claimed for other size, shape, weight and configurations, but window people ignore the facts in the interest of peddling and advertising.

Dick


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## oberon (Apr 29, 2006)

Unicornz0 said:


> Will it be listed on the window as the "U" value or the "total unit u value"?
> 
> Thanks Again,
> Uni


No problem, you are welcome.

If windows have an NFRC label it will list "U-factor" (same thing as U-value) and it will be the rating for the entire unit, not just the glass.

CoG U value is only useful when comparing specific glass package make ups - for example if you wanted to compare the perfomance values of two different Low-E coatings in an identical IGU configuration.


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## Windows on Wash (Aug 30, 2011)

concretemasonry said:


> Just try to find a documented and universally accepted "U" value for window assembly.
> 
> A wall with R19 insulation can have an actual R9, just as a comparison with the real world. The "Pink Panther" does not like it or dispute it, since the test is a universally accepted laboratory testing industry (costly and realistic).
> 
> ...


CM,

U-Factor is the entire assembly tested as a complete unit. 
*U-Factor *

_U-factor measures how well a product prevents heat from escaping. The rate of heat loss is indicated in terms of the U-factor (U-value) of a window assembly. U-Factor ratings generally fall between 0.20 and 1.20. The insulating value is indicated by the R-value which is the inverse of the U-value. The lower the U-value, the greater a window's resistance to heat flow and the better its insulating value._

You are correct in that there are different performance values for other operators and glass packages, but if it has a sticker on it, it has to be tested and certified at that value. 

They don't require a size to be tested as that would require a bunch of tests but because the glass is typically the more high performance aspect of the window compared to many frame materials, the larger size is not usually any more detrimental to the U-Factor.


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## Windows on Wash (Aug 30, 2011)

In Michigan, I would go with triple pane windows and perhaps some higher SHGC windows on the Southern elevation.

After that, CM is 100% correct in that drapes and thermal shades will help out quite a bit and should be used. Beware of condensation issues when you run blinds and shades though.


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## Unicornz0 (May 22, 2012)

First, I want to thank everyone for their input & help with my window purchase.

What do you think?

Now to the point, I’ve asked Wallside Windows for their specifications.
The Salesman told me his Manager had him send me the spefications sheet.
I’m thinking all is fine & well, until I went to the NFRC website & see none of the (CPD #) model numbers match!

I’ve asked the Salesman to clarify & direct me to the specifications on the NFRC website, for my proposed installation (double Slider) since the (CPD #) model numbers on the specifications sheet sent are not listed on the NFRC website.
I’m waiting for a reply.

Does anyone know of any reputable, local Michigan replacement window companies?
I’ve called Majic Fiberglass Window, & am not at all pleased with them & their Better Business Bureau ratings.

Thanks Again,
Uni


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## HomeSealed (Jan 3, 2008)

Sunrise is a nice product made right in MI. I'd contact them and ask them to give you a dealer referral (or 2) in your area. The Restorations line is very good. Softlite, Okna/HiMark, and Polaris are great options as well.


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## Unicornz0 (May 22, 2012)

HomeSealed said:


> Sunrise is a nice product made right in MI. I'd contact them and ask them to give you a dealer referral (or 2) in your area. The Restorations line is very good. Softlite, Okna/HiMark, and Polaris are great options as well.


Thanks HomeSealed,
I will.
Uni


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## Windows on Wash (Aug 30, 2011)

You are in Sunrise territory there in Michigan. 


Very solid window along with the different brands that HomeSealed mentioned.


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## Unicornz0 (May 22, 2012)

HomeSealed said:


> Sunrise is a nice product made right in MI. I'd contact them and ask them to give you a dealer referral (or 2) in your area. The Restorations line is very good. Softlite, Okna/HiMark, and Polaris are great options as well.


Hello Again,

I’m also interested in fiberglass windows because of their specifications on NFRC.org
I had a sales call with Majic Window, & their salesman was abysmal.
He was very insulting & told me the information on NFRC.org is BS, & crap!
He was very upset when I asked about the model # of the Inline Fiberglass window, which would be used for my installation. I showed him on the PC the different Inline Fiberglass Ltd models. He didn’t want me to make any comparisons.
He told me he didn’t want my business because of my questions (which he couldn’t answer), & walked out of the sales call.
I’m waiting to hear from his sales mgr.

Please tell me are there any other retailers of fiberglass windows in southeast Michigan?
Also how are fiberglass windows bonded at the seams?

Thanks Again,
Uni


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## HomeSealed (Jan 3, 2008)

Fiberglass windows are mechanically fastened. This is a MAJOR detriment as vinyl products go (that is why the vast majority are welded), but not quite as big a deal for fg since it doesnt move quite as much. 
I'm sorry to hear about your experience with that dealer. The Inline product is one of the higher performing fg products that you'll find available in the US.


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## Windows on Wash (Aug 30, 2011)

I would look for a Marvin Infinity as well. Should be a dealer somewhere out there by you.


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## Unicornz0 (May 22, 2012)

HomeSealed said:


> Fiberglass windows are mechanically fastened. This is a MAJOR detriment as vinyl products go (that is why the vast majority are welded), but not quite as big a deal for fg since it doesnt move quite as much.
> I'm sorry to hear about your experience with that dealer. The Inline product is one of the higher performing fg products that you'll find available in the US.


Some of my lower level windows are joined mechanically at the seams.
They were in the house when I purchased it.
How can I tell if they are FG, or even which manufacturer?

Thanks Again,
Uni


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## HomeSealed (Jan 3, 2008)

Those appear to be of the cheapo vinyl variety. You may be able to find a sticker somewhere in the jambs that has some identifying marks.


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## Windows on Wash (Aug 30, 2011)

Slider + Mechanically fastened sill = problems down the road in most cases.


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## Unicornz0 (May 22, 2012)

Hello Again,

Buying Windows should not be this difficult.

Salesmen from 3 different companies have been out to make their pitch,
None have been able or willing to tell me the complete NFRC CPD# so I can make sure what they are telling me is what will be installed.
They all seem to be less than candid, & 
seems no other Buyer has asked then for this information.

I may have identified 1 of the windows I’m interested in because it is the only triple pane Wallside Window with the ratings: 
U-.22/ SHGC-.26 / VT- .42 on the NFRC website (the condensation rating is not on the windows sticker).
This window does not let in nearly as much light as their double pane,
but if it will buffer me significantly better from outside noise, &
will save me significantly more money on utility bills,
I’d likely buy this 1 instead of the double pane.
How can I get a reasonable idea of how much more I will save on utility bills if I buy the triple pane?
Seems to me there is now way to know because of all the variables involved.

I’d like to get more specifications as discussed on the NFRC website, but the information is not readily available.
I’m still waiting to hear back for WW Sales Mgr.

The Wallside Window Double pane is rated U-.30/ SHGC- .29/ VT- 53
The Triple is rated: U-.22/ SHGC-.26 / VT- .42

Please tell me what you think of the Wallside Double & Triple pane windows?

Thanks Again,
Uni


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## Windows on Wash (Aug 30, 2011)

Numbers are okay.

That VT number drop from double to triple is pretty consistent with what the averages are but the thermal numbers are a bit below what you will see out of the really top notch performers.

Example: I know of triple pane argon windows that get to U-Factor of 0.20 and as low as 0.15.

May not seem by much when dealing in the hundredths, but a drop from 0.22 to 0.19 is 16% improvement. 

If you are going to have a darker window, you might as well have the much better thermal performance as a result. 

At a 0.22, I would prefer to have a window that is 0.25 in double pane.

Don't buy the triple thinking the sound attenuation will be that much better, it will not.


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## Unicornz0 (May 22, 2012)

Windows on Wash said:


> Numbers are okay.
> 
> That VT number drop from double to triple is pretty consistent with what the averages are but the thermal numbers are a bit below what you will see out of the really top notch performers.
> 
> ...


Thanks for letting me know the numbers are OK.
I can't find any sound specifications on the windows I've been seeing.
I can only assume the triple pane is "somewhat" better than the double.

I'm a bit rusty on my math, but I think there is only a 3% difference between
the .22 & the .19 specification.

Thanks Again,
Uni


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## Windows on Wash (Aug 30, 2011)

There are 3 Hundredths of a difference but U-Factor is not a percentage representation. It is the inverse of R-Value.

U-Factor of 0.19 = R-5.25
U-Factor of 0.22 = R-4.55


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## Unicornz0 (May 22, 2012)

I've narrowed my selection to 3 choices below.
The Wallside Windows are vinyl & the Majic Windows are fiberglass.

WALLSIDE DOUBLE HORIZONTAL SLIDER
U-FACTOR .30-SHG .29-VT .50-CR 58

WALLSIDE TRIPLE HORIZONTAL SLIDER
U-FACTOR .21-SHG .26-VT .42-CR 69


MAJIC HORIZONTAL SLIDER-DOUBLE PANE

U-FACTOR .29-SHG .22-VT .50-ER.16


I'm gravitating towards the Wallside triple pane windows.
The Majic fiberglass windows are 42 % more expensive than the Wallside triple pane windows.

I don't really like the low VT on the WW triple pane, but I think this will be my best choice.
They will be installed in 2nd story bed/bathrooms.

What do you think?

Thanks Again,
Uni

P.S. There is another Wallside triple pane window, krypton gas between the panes:

UI7-SHG26-V42-CR69

The Salesman says the krypton gas will cause the price of the window to triple.

Does this price increase seem justified just for the addition of krypton gas?


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## concretemasonry (Oct 10, 2006)

Buy waht you like since you will never really notice the differences in the numbers between the brands (with plenty of zeros and decimals).

The important thing is make sure the installation is good enough to get the benefits. The biggest problems with windows is the installation, so a bad window with good installation is far better than a good window with bad installation. - I learned this doing mosture/mold investigation and problems due to the structural deformation. I never got into the infiltration problems, but they were evident, but when you are brought in by insurance companies to address certain problems with claims. Check to see if the installer is certified (there is usch a thing that required by some window suppliers that provide installation)

Dick


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## Unicornz0 (May 22, 2012)

*Jointed fiberglass window frames*

I think I have jointed fiberglass window frames, The sides of the frame are not soft & flexible like my newly triple pane installed vinyl windows, & the frame material is only 1/8" thick
My vinyl window frames are ~1/4" thick.
The problem with them, is the joints are transferring or leaking cold air.
What is the best material to use to seal the joints? 

Thanks,
Uni


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## Windows on Wash (Aug 30, 2011)

Quality sealant with a good joint class rating.


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## Unicornz0 (May 22, 2012)

Windows on Wash said:


> Quality sealant with a good joint class rating.


Thanks,

Which is a suitable sealant & what is a good joint class rating for this application.


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## Windows on Wash (Aug 30, 2011)

What color is the frame?


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## Unicornz0 (May 22, 2012)

Windows on Wash said:


> What color is the frame?


White.


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## concretemasonry (Oct 10, 2006)

A repeat - The installation is the most critical item since about 2/3 of all windows are installed improperly, so all the decimals and lab tests mean little by comparison, especially if the is from moisture from the sides (within 10 feet) or from the top (20 feet).

If you have any FG near a poorly installed window it will never dry out and every R-value can be cut by well over 50% (forgrt about the advertised claims with a lot of zeros for imply accuracy in the ideal world.

Remember - a window is just a complicated hole in a wall that decreases thermal efficiency, but can be pretty.

Dick


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## DIYHomefit (Aug 28, 2013)

Haha Dick, loved your quote "Remember - a window is just a complicated hole in a wall that decreases thermal efficiency, but can be pretty" !

This is really a first I'm hearing about triple pane (or triple glazing for us in the UK). Living in a cold country, I'm thinking about triple pane - should be cost effective in the long run. But if I have double panes fitted in already, is there really any point? :huh:


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## Unicornz0 (May 22, 2012)

This is really a first I'm hearing about triple pane (or triple glazing for us in the UK). Living in a cold country said:


> I've got double pane windows installed elsewhere in the house, & I'm thinking I will have someone hold a heat lamp outside near the windows, then put my hand against the inside pane to judge the heat gain. Since my double pane windows are intact, this is the simplest way I can judge their efficiency, since I do not have the name of their manufacturer or their specifications.
> 
> One of the salesmen did this test with windows he was trying to sell me.
> Seems reasonable to judge heat gain (& loss?).
> Now I have to find a cheap heatlamp!


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