Image Credit: Alex Wilson
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I just spent three days at the American Institute of Architects annual convention in Washington, DC, including a fair amount of time at the massive trade show there. I didn’t make it all the way through the acres of exhibits over the eight hours or so I walked the floor, but I saw some really interesting products. I’m highlighting here a few of the windows and glazing-related products I found.
SunGuard PVGU from Pythagoras Solar and Guardian Industries
Guardian Industries, one of the world’s largest glass manufacturers, showed off two new products at the show. One of these was a unique building-integrated photovoltaic (BIPV) glazing system developed by Pythagoras Solar and marketed by Guardian.
Most BIPV Glazing systems have thin-film or crystalline PV cells integrated into the glass directly, so the visible transmittance and daylighting potential are significantly compromised. Pythagoras has developed a unique solution to this problem: an insulating glass unit (IGU) with integral bars of tiny PV cells that intercept most of the solar energy striking the outside of the glass.
When you look out through Pythagoras glazing, the view is distorted, but some visibility is maintained and a remarkably high 49% visible transmittance is still achieved — so daylighting performance is still very good. When viewed from the exterior (see photo), you mostly see the PV cells due to the way light is refracted by the glazing.
The Pythagoras BIPV glazing produces up to 11.15 watts per square foot, which the company claims is up to three times the power density of most other BIPV glazings. The overall module efficiency is up to 12%, while the U-factor (assuming argon gas-fill) is a respectable 0.28 and the solar heat gain coefficient is 0.14 — helping to control overheating. For more on this, visit Pythagoras Solar and Guardian’s SunGuard PVUG.
SunGuard EC dynamic glazing from Soladigm and Guardian Industries
Also on display in the Guardian Industries booth was a new dynamic glazing product: Soladigm glass. A few weeks ago I wrote about dynamic glazing, which can be tinted on demand to control glare and solar heat gain, and specifically SageGlass, the first company out of the gate with such a product that is commercially viable. Soladigm glazing, branded as SunGuard EC by Guardian, is made in Mississippi. Like SageGlass, it is an electrochromic glazing that uses electric current to tint the glass.
Soladigm’s coating is added to the #2 surface (the inner surface of the outer pane of glass in an IGU), and it can be used with clear glass or combined with a low-e coating on the #3 surface (the outer surface of the inner pane of glass). When used with clear glass, the tinting ranges from a visible transmittance of 62% and a solar heat gain coefficient (SHGC) of 0.47 in the untinted state to 2% / 0.09 in the fully tinted state. When used with low-e glass, it provides 48% visible transmittance and 0.29 SHGC untinted and 2% / 0.07 fully tinted. It is also available with four intermediate levels of tinting. The U-factor for these IGUs (assuming argon gas-fill) is 0.29 with clear glass and 0.24 for low-e glass and is the same whether tinted or not.
Like SageGlass, Soladigm’s coating consumes a small amount of electricity to achieve the tinting (0.1 watt per square foot) and about a third as much electricity (0.03 W/ft²) to maintain the tinted state. When the electric current is shut off, the glazing reverts to the clear state. For more information, visit Soladigm or Guardian.
Graham fiberglass windows
I have just completed work on a new BuildingGreen report on windows, for which we did extensive research on the window industry, so I was surprised to come across a product (and frame material) that I had never heard of. Graham makes a high-performance window, primarily for commercial-building applications, that is available triple-glazed with U-factors as low as 0.15.
What is unique about Graham windows is the frame material: a fiberglass composite that is 80% glass fibers and 20% polyurethane resin. Fiberglass is a highly durable and strong window frame material that is much more thermally stable than vinyl (PVC), but all other fiberglass windows I am familiar with are made with a polyester, rather than polyurethane, resin. According to Graham, with polyurethane you can have a higher percentage of glass fiber, achieving better strength properties. (I learned later at the show that it is harder to bond coatings to polyurethane resins than to polyester resins, which may explain the predominance of polyester-based fiberglass composites.)
Graham windows, including the fiberglass frames, are manufactured in York, Pennsylvania. They are typically fitted with Cardinal glass, which is available with various types of low-e, including Cardinal’s new LoE-i89 coating for the #4 surface (facing the room) of an IGU. For more information, visit www.grahamwindows.com.
Marvin Integrity windows with triple glazing
For years I keep asking the largest window manufacturers when they will be introducing higher-performance products. Finally my wishes came true with Marvin’s fiberglass Integrity line. I learned at the Marvin booth that the company will be rolling out a triple-pane version of its popular Integrity line around the end of the second quarter of this year, though one of the Marvin reps in the booth allowed as to how that target date might slip.
There is nothing yet on the Marvin website about this window, so I haven’t been able to examine performance specifications, but I think it will be a good choice for budget-conscious home builders and homeowners. It won’t match the high-end European Passive House windows in performance, but it will still be pretty good. Like most other fiberglass windows, the Integrity line is a fiberglass-polyester composite. A nice feature of the Integrity line is that only the exterior is fiberglass; the interior is wood, providing a nicer, warmer feel.
Alex is founder of BuildingGreen, Inc. and executive editor of Environmental Building News. He also coauthored BuildingGreen’s special report on windows that just came out. To keep up with Alex’s latest articles and musings, you can sign up for his Twitter feed.
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12 Comments
Pella?
Alex - did you see anything about Pella's triple glazed product?
Pella's triple-glazed windows
I didn't make it to Pella's main booth at the AIA show. They have had their Energy Panel windows, which I've long liked, but I think I heard that they are coming out with a true triple-glazed window--as is Andersen (finally!).
I did stop by EFCO's booth, though. EFCO is Pella's commercial curtainwall company, and they have significantly improved the thermal breaks in their aluminum-framed curtainwall and window systems, and they can provide triple-glazed units. Here's a link to their website: http://efcocorp.com/.
Response to Jason Peacock
Jason,
Do a search on "Intus" on the GBA site and you'll get links to 18 articles. I reviewed Intus windows in an article published 8 months ago: New Green Building Products.
The Intus windows that are most affordable are vinyl. For some buyers, that's a problem. Others don't mind.
U-factors for Intus
Jason,
I think your quoted U-factors for frame and whole-window are off by a decimal point, aren't they? Shouldn't those numbers be 0.16 and 0.12, respectively?
Intus is a game changer!
Alex, Great article. I can't wait till more building products are integrated with solar PV. It just makes sense. I'm sure we'll see an evolution of building materials within the next few decades that none of us would have dreamed of. It's an exciting time to be in the industry. The standard paradigms are shifting. If you haven't already, take a look at Intus Windows. They are hitting higher performance benchmarks that you've been waiting for from the larger manufacturers and they're doing it now. Their triple glazed prices are competitive with all major US manufactures double glazed options. It may be newsworthy even for an article. Now is a great time to build a home and Intus makes it financially possible to use triple glazing.
U-0.088 (center of glass). That's an R-11.36. I don't see Marvin approaching this anytime soon.
U-0.16 (frame).
U-0.12 (whole window).
SHGC of 0.62
DP rating 70
Air Leakage 0.01
Pricing is again equally amazing. It basically takes away the argument that triple glazing is too expensive.
Intus UPVC is not your typical vinyl window
Martin, Intus has wood frame windows wood or aluminum clad with very competitive pricing. The glass values all stay the same. Their UPVC option is the most popular. They also have a passive house certified thermally broken aluminum clad window that is beautiful.
The "U" in UPVC stands for Unplastisized. Plastics that are added in typical vinyl windows make the extrusion process easier. Plastics make the material less dimensionally stable and susceptible to cracking and warping. Plastics don't allow the material to be recycled. UPVC is very stable in extreme temperatures and can be upcycled indefinitely into further production. The frames are very rugged and also have steel reinforcement in the center of the extrusions. The company that makes the extrusions is the largest in the world, Schuco. They are in Germany and adhere to the European Union's strictest manufacturing standards for restriction of toxics. These frames will most likely outlast the wood that holds them in place.
Alex, thanks for the corrections.
Response to Jason Peacock
Jason,
Unless Intus has switched suppliers, Schuco does not supply their vinyl lineals. According to Intus representative Aurimas Sabulis, the company uses vinyl lineals manufactured by Deceuninck Group, a Belgian company.
The "U" in UPVC
Jason,
From the research I did, plasticizers are not used in any American vinyl window extrusions and never have been. I do not believe there is any difference between UPVC and the PVC used in American windows. I asked two contacts in the vinyl industry about this a few months ago, and both were quite adamant about that. Phthalate plasticizers are widely used in flexible vinyl, including vinyl flooring, wire sheathing, and shower curtains--where it can account for 40-50% of the total weight I think. Vinyl window extrusions and vinyl pipe do not require these plasticizers. This is an important issue, because phthalate plasticizers are endocrine disrupters, and we want to avoid them.
Schuco
Martin,
Yes, you're right Deceuninck Group makes the UPVC frame. It's Schuco that makes Intus aluminum frames. My mistake.
Alex, I'm curious if other manufacturers have other additives besides phthalates plasticizers. It is my understanding that the European Union has much stricter oversight on manufacturing and restriction of hazardous substances than the EPA here in the USA.
Nevertheless, Intus has remarkable performance at a great price. I re-read your article on different windows from a few months back and one thing I'd like to clarify is that Intus Premmier 78 is a wood frame, aluminum clad option closer to $60 / square foot. We've been surprised at the level of quality at this price.
Sun Gaurd
Looks great for skylights but who will sacrifice their view?
Response to Jason Peacock
Jason,
The Intus prices guidelines I included in my article came straight from Intus. Obviously, large windows (especially large fixed windows) cost less per square foot than small windows (especially small operable windows), so the price per square foot will vary.
Window pricing
Martin,
We worked with Linwood windows for a bit and they told us $100 - $120 / sf. When we got a quote it came it at $450 / sf. Our lesson was that you can't always believe what a manufacturer tells you. The nice part with Intus is that their prices keep coming in lower than their general pricing information. There are still good surprises in this industry and Intus is changing the way I look at what you can buy with your $. In the past you'd spend at least twice as much for a window with these stats.
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