R-10 on a window?

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mman
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R-10 on a window?

#1 Post by mman » Fri May 05, 2006 3:25 pm

There is a company here that boasts an R value of 10. How is that possible when that translates to a U-Value of .10? I understand that it is triple pane with a foam core frame, but even so, all data I've seen on similar products goes to (lowest) a .20 or there abouts. Maybe even a .18 is beleivable, but a .10? Any help here would be appreciated.

Tru_blue
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R-10

#2 Post by Tru_blue » Fri May 05, 2006 4:26 pm

They are probably citing the CENTER OF GLASS as R-10. The lowest U-value that you mentioned of .20 to .18 is presumably the honest, OVERALL TOTAL UNIT U-value. If a window has a total unit U-value of let's say .18 (about as low as it goes), the corresponding center of glass could possibly be close to R-10 but the overall R-value would usually be in the upper 4s. People should not fool with mother nature, spit into the wind, tug on Superman's cape, or mix their center-of-glass and total unit R and U values!

XSleeper
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#3 Post by XSleeper » Fri May 05, 2006 5:44 pm

When window salesman start talking about the R-values, that's usually a good time to look in the yellow pages for someone else. Besides the points that tru_blue mentions, they could also be referring to a foam-filled frame, which "hypothetically" would be R-10 or more. But since 90% of the window is glass, the overall energy efficiency of the window is a bigger concern.

My advice to people I talk to is to ignore talk about r-values when dealing with windows and rely soley on the NFRC u-value ratings. The NFRC ratings may not be perfect, but at least they seem to compare glass fairly.

mman
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#4 Post by mman » Mon May 08, 2006 9:55 am

I agree 100%. Some sales people just don't see the logic of those statements and insist on using R values for windows when we all know R values for windows stinks... a wall being R 30 and a window being R 3?? Not that impressive. Stick to the industry standards and the consumer becomes more educated rather than confused.

Integra
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Re: R-10 on a window?

#5 Post by Integra » Thu Jan 14, 2010 2:52 pm

Southwall Technologies just announced that they have been able to achieve an R-20 rating. It's pretty fascinating stuff. Check their website.

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Windows on Washington
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Re: R-10 on a window?

#6 Post by Windows on Washington » Thu Jan 14, 2010 4:34 pm

When this technology is affordable, it will have applicable value at that point.

For right now, there are a myriad of things that homeowners can do to make a more substantial impact on consumption besides +$1,000/per unit windows.

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Window4U (IL)
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Re: R-10 on a window?

#7 Post by Window4U (IL) » Thu Jan 14, 2010 11:38 pm

The product he's talking about is the glass package put in to Serious's U-.09 casement. At over $2000 per single window dealer cost it is not practical.

Integra
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Re: R-10 on a window?

#8 Post by Integra » Fri Jan 15, 2010 8:18 am

We have a lot to be thankful for with this tax credit. It has really awakened the window industry and forced innovation where things have been rather stagnant for a while. We're seeing new glazings, spacers, extrusions at a rate that we haven't seen in many years.

The central issue that keeps coming back in my mind is that we're putting R-4 to R-8 windows into walls that are R-11 to R-15. That leaves a lot of room for improvement. That means a bright future for us as technology increases, and the price of that technology grows more affordable.

Exciting times are ahead!

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Windows on Washington
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Re: R-10 on a window?

#9 Post by Windows on Washington » Fri Jan 15, 2010 8:36 am

The difference between an R-6 window and an R-10 window on overall wall R-Factor is very light when you run the numbers. The price differences are not slight at all.

2 windows at 3' by 6' in a wall that is 12' wide by 9' tall. Overall impact in R-value on an R-15 wall:

R-6 window (at $800 per opening) makes the overall wall an R-12

R-10 window (at $2,000 per opening) make the overall wall an R-13.3

It will take 50+ years for the consumer to recover that $2400 difference in the two windows in energy savings.

Integra
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Re: R-10 on a window?

#10 Post by Integra » Fri Jan 15, 2010 10:19 am

I'm sure there is hope though. I'm sure the window cost will decrease and the energy cost will probably increase. It really is an exciting time to be in the window business.

pilot

Re: R-10 on a window?

#11 Post by pilot » Wed Jul 28, 2010 4:41 pm

Windows on Washington wrote:The difference between an R-6 window and an R-10 window on overall wall R-Factor is very light when you run the numbers. The price differences are not slight at all.

2 windows at 3' by 6' in a wall that is 12' wide by 9' tall. Overall impact in R-value on an R-15 wall:

R-6 window (at $800 per opening) makes the overall wall an R-12

R-10 window (at $2,000 per opening) make the overall wall an R-13.3

It will take 50+ years for the consumer to recover that $2400 difference in the two windows in energy savings.

This should be posted on almost every question related to triple pane, Heat Mirror and the gov'ts R5 program.

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