Is it possible for Double Pane Glass to have U Factor of Triple Pane

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bajinganin2
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Is it possible for Double Pane Glass to have U Factor of Triple Pane

#1 Post by bajinganin2 » Tue Jun 23, 2020 2:29 pm

I'm currently considering Sunrise, Polaris and Provia Windows to enclose my porch area with 2 big sliders(92x53) and 2 big picture windows(84 x 53). The rest of the house has Schuco Triple Pane Glasses Widows, which I just found to have NFRC label with U-Factor of 0.22.

The best Double Pane Slider and Picture WIndows from Sunrise is Omega 12 with Interior Low E option. The U-Factor is 0.25 and 0.22 respectively.
The best Double Pane Slider and Picture Windows from Polaris is Ultraweld Supreme. The U-factor is 0.27 and 0.26 respectively.

If I want U-factor of 0.23 or better, I need to go Triple Pane with both Sunrise and Polaris, which will increase the cost. I'm installing 2 picture windows and 2 sliders

The Provia double panel(Endure ComfortTech-DLA-UV-HC) seems to have surprisingly good U-factor. Their sliders and Picture windows have U-factors of 0.23 and 0.22 respectively.

Should I go with Provia Double Pane? or should I just stick with Sunrise? SHould I do Triple Pane? I'm soliciting thoughts :) I'm in Central Jersey.

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HomeSealed
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Re: Is it possible for Double Pane Glass to have U Factor of Triple Pane

#2 Post by HomeSealed » Tue Jun 23, 2020 3:19 pm

You are going to want to take a step back and look at the other thermal numbers (as well as structural) in this comparison. U value is the "big one" as far as thermal ratings are concerned, that said, if they are achieved the wrong way, you can have negative side effects up to and including a reduction in the very energy efficiency that you are trying to maximize.

In NJ, you are going to want to take a look a SHGC (Solar heat gain), VT (Visible transmittance/light) and CR (condensation resistance). In short, can a double pane window get a triple pane-ish rating of .22-.23? Yes. Will it serve you well in NJ? Not likely. To achieve that number, you will get glass that is very dark, blocks solar heat more than you'd like (you spend more time and $ heating your home than cooling), and will have reduced condensation resistance as well due to that interior surface coating. Those are two technologies that are relevant when properly applied, but both aspects are better used in warmer areas than NJ.

IMO, your best bet is to opt for triple pane glass in any of those lines. If its not an option due to budget or other, get a standard surface 2 (or 3 for Polaris) low e coating on double pane glass. This will yield a U value of .26-.29 or so in these products. Some Okna lines get .24 -.25 with that same coating, but that's about the lowest that you will find without resorting to dark, low solar gain glass and a surface 4 (interior) coating.

Lastly, in central NJ, you should give AGM a call and speak to Paul. He'd be able to guide you through this stuff from a local perspective, and while you have some solid window choices there, he can offer choices that best those numbers.

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Windows on Washington
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Re: Is it possible for Double Pane Glass to have U Factor of Triple Pane

#3 Post by Windows on Washington » Wed Jun 24, 2020 5:13 am

Can't add anything to the technical assessment that HomeSealed laid out. It's spot on.

I would also recommend that you give Paul at AGM a ring too. Solid guy who runs a great shop there. Can't go wrong with those folks.

bajinganin2
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Re: Is it possible for Double Pane Glass to have U Factor of Triple Pane

#4 Post by bajinganin2 » Fri Jun 26, 2020 10:37 am

Thank you all!!

bajinganin2
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Re: Is it possible for Double Pane Glass to have U Factor of Triple Pane

#5 Post by bajinganin2 » Fri Jun 26, 2020 10:37 am

Thank you all!!

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