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Looking Through Windows — Part 6

It looks like we'll be buying Bieber windows from France instead of Unilux windows from Germany

Image 1 of 2
Triple-glazed Bieber window.
Image Credit: Bieber USA
Triple-glazed Bieber window.
Image Credit: Bieber USA
Chris Briley's drawing shows the installation details for the Bieber windows at Edgewaterhaus. [Editor's note: many designers would advise the installation of through-wall flashing under the exterior stone window sill. Directly above this through-wall flashing, best practice requires the installation of weep holes or a plastic mesh material that allows for drainage to the exterior.]
Image Credit: Chris Briley

[Editor’s note: Roger and Lynn Normand are building a [no-glossary]Passivhaus[/no-glossary] in Maine. This is the tenth article in a series that will follow their project from planning through construction.]

Enough suspense on windows.

It’s a Bieber! And yes, that’s our final decision. We’ve made a sizable cash deposit and started precise shop drawings for the windows.

It had been a tortuous four, yes, four long months working with the local Unilux window retailer, Hancock Lumber, to get the right configuration of these German manufactured windows to meet our performance requirements. And that was only to specify the windows.

In defense of Hancock Lumber, this was a new line of windows recently added to their more traditional line of Andersen and Eagle windows. And there was certainly a learning curve on our part, particularly regarding the importance of high Solar Heat Gain Coefficient glazing – a high SHGC enhances the interior heat gain we need in winter to meet the Passivhaus standard.

Goodbye, Unilux

Still, the Hancock window team never seemed to grasp our need, and how the Unilux windows could best fit that need. Would matters improve after ordering, through preparing shop drawings, shipping, importing, customs, delivery, install, and any potential warranty issues? We lost confidence in the product and the distributor last October and decided to move on, despite having sunk much time and money in design and consultant fees.

We looked at Thermotech windows, which are made of pultruded fiberglass. This material is said to be as strong as but less costly than wood. It’s also stronger than vinyl, but unlike vinyl, expands and contracts to temperature changes at the same rate as glass, thus ensuring a better long term seal between glass and sash. We heard mixed views from a few builders and homeowners we met with Thermotech windows. But after seeing the beauty of the Unilux wood core/aluminum clad windows, we knew we would not want to get a uPVC or fiberglass window.

Intus or Bieber?

We only looked at Passivhaus-certified wood-core, aluminum-clad windows. We narrowed our search to Intus and Bieber windows. (Intus also manufactures a Passive House certified uPVC window at a much lower cost.)

Intus is manufactured in Lithuania, with a U.S sales office located in Washington D.C. Intus is a visible presence at many Passivhaus events. Maine Green Building Supply, located in nearby Portland, Maine, recently became an Intus retailer. How convenient!

Bieber is manufactured in the Alsace region of France, and has U.S. sales offices in Newport Beach CA and New York City.

Both Intus and Bieber are European-style tilt/turn windows. Both use high quality hardware with multiple locking points between the sash and frame and several gaskets around the perimeter to securely close the window. Both have thermal breaks in the window frame and sash: Intus uses foam between the aluminum cladding and the wooden frame; Bieber uses an inert material routed into the core.

Visiting the Intus and Bieber showrooms

I traveled to the Intus sales office in Washington DC, and then the Bieber sales offices in Manhattan New York in early December. What a refreshing change: the sales staff were thoroughly knowledgeable about the technical details of their windows, AND were conversant with the Passivhaus standard.

I looked at window samples and asked dozens of questions: How is the frame assembled? Can the glazing be replaced without replacing the sash? Can gaskets be replaced? How is the cladding applied to the wood core? How do you adjust the hinges so the sash aligns perfectly within the frame? What glazing options are available? Can the windows be factory stained? What is the shipping, customs, and delivery process? Will a factory rep be present for unloading and offer technical assistance to install the first few windows? How are the windows installed? What is the warranty? How are warranty and replacement issues handled?

I liked what I heard and saw about both the Intus and Bieber windows. My overall impression was that these windows were exceptionally beefy, well engineered, meticulously assembled, and very attractive European-style windows. Since both windows were Passivhaus-certified (Unilux was not), both had reasonably similar performance in terms of frame widths, frame and sash U-factors, glazing U-factors, SHGC, and VT factors for PHPP input.

Pluses and minuses

That’s not to say there are not differences between the two. The Intus windows can be factory stained (you choose from among a handful of stain options) at no additional cost, and overall the Intus windows were less costly than those from Bieber.

Bieber offers a very attractive concealed hinge for venting units at no additional cost, but there is an an additional charge for factory staining. Bieber also offers slightly better glazing (0.63 vs. 0.62 SHGC). Spread across an expansive south-facing glass, that 0.01 improved SHGC makes a noticeable difference in a cold climate when trying to attain the very low Passivhaus heating goal of 4.75 KBTU.

Bieber offers other customization options, such as milling an angled slot to receive the side jambs when the window is installed in the rough opening. The window also features a very narrow exterior cladding profile; it’s designed to be “packed” with exterior styrofoam insulation during installation. This improves the frame U-factor, eliminating a thermal bridge within the window frame.

Bieber windows have better screens

They are both very nice windows that would offer performance, comfort and elegance if installed in Edgewaterhaus. So how did we decide?

Screens! Screens were the primary tipping point in favor of Bieber. Screens are an absolute necessity here in Maine from late spring to the first frost. Mosquitos, gnats, horse flies, deer flies, and black flies abound, feasting on warm blooded skin. These tiny to large size buggers leave a bite trail of rose colored pinpricks to large welts on your exposed skin.

If you don’t have window screens in Maine, you might as well get non-venting windows. Edgewaterhaus is perched on a bend along the intertidal area of the Saco River, and the large marshy area by the river bank provides a prolific breeding ground for ‘squitos. So having screens on all venting windows was de rigueur.

As well made as the Intus windows appear, the fixed screens seem to be an engineering afterthought. (In our travels to Europe, we have noted few buildings had window screens.) The Intus fixed screens attach to the frame with a series of brackets that overlap and compress the outermost gasket on the window. At best, they look clunky when the window is open, and I wondered if the compressed gasket affects performance. Intus offers an exterior mount pull-down screen, but Edgewaterhaus has many windows units with a mix of fixed and venting window panes. We did not like the aesthetics of an exterior screen mounted over just the venting pane. The Intus sales rep said the factory is working on an improved fixed screen design.

In contrast, the Bieber screen mounts from the inside with a clasp that fits into a slot in the frame. We also liked the concealed hinge option for the sash. With this no cost option, all you see from inside is the wood sash and frame with no visible “door style” hinges typical of European style tilt-turn windows. Very nice!

Bieber it is

So we decided to go with Bieber windows. The photo at the top of the page shows the Bieber Passivhaus window that we have selected for Edgewaterhaus: Bieber Optiwin window Wood/Aluminum series.

Our architect, Chris Briley, started to replace the Unilux windows in the CAD drawings with Bieber windows. The Bieber window has a much narrower exterior aluminum clad profile than the Unilux, as it is designed to be “packed” with exterior insulation. Chris said packing the frames would slightly reduce the thermal bridge in the wood frame, but would also move the window frame further into the wall, complicating exterior weatherproofing around the window frame. Bad tradeoff. So, no “packing” for us.

But the Bieber design also lent itself to be installed higher in the window rough opening, effectively adding several inches in height of higher performing glass within the same rough opening dimension. Now several inches of additional glass doesn’t seem like much, but spread it across the entire south facade, and now we’re talking something more substantial. The redesign of the west wing of the house, described in my previous blog, “cost” us 25 square feet of glass. Moving from Unilux to Bieber recaptured nearly all of this glass, which will surely help in the Passivhaus certification analysis.

Equally important, Chris has designed a recessed cavity to conceal shades above each window (at the interior side of the header). The detail still leaves some 6 inches of wall showing above the window. A very nice touch. The detail drawing (below) shows the recessed cavity.

The first article in this series was Kicking the Tires on a Passivhaus Project. Roger Normand’s construction blog is called EdgewaterHaus.


  1. wjrobinson | | #1

    I hereby nominate Chris
    I hereby nominate Chris Briley for sainthood status.

    Any guess how many total manhours were invested in the window selection including all players and travel time and expenses and architect billable hours? Guessing a 1000

    hours and $10,000 in costs.

    Cost of windows per sqft, total window and door cost?

  2. user-1087436 | | #2

    I second the nomination by Mr. Builder.
    Enough said.

  3. user-1087436 | | #3

    Honestly, I can't decide
    Honestly, I can't decide whether this is (a) pioneering work, a kind of necessary tedium that will help bring about a new standard for building, or (b) sheer lunacy. Right now I'm leaning toward (b). I mean, it's a HOUSE.

  4. Beauly | | #4

    Too much!
    Build the house already! Way too much time any money on windows! Wow!

  5. dankolbert | | #5

    Easy, killers
    The house has been under construction for some time now. I have met Roger several times and applaud him for the cautious approach he's taken on the project. He knows what's important to him as the homeowner and is making sure he nails down the details before construction. I believe these blogs are actually "reprints" from his own blog on the project. I know with certainty that they are not appearing here in real time - they had already broken ground when his entry on choosing a contractor appeared.

  6. LucyF | | #6

    Windows - thank you.
    I do appreciate reading about these window issues partly because there is no way I could put that kind of thought and effort into choosing windows. One reason I don't have to do that is that I live in mixed, humid climate with more cooling than heating issues.

    I think Roger helps us by doing all of this homework and summarizing it for us with our having to go through the work. I do appreciate that. Thank you.

  7. Christopher Briley | | #7

    Sainthood? Pioneering? Lunacy?
    To say that this has been the most deliberate, surprising, and lengthy window decision I’ve been a part of, is an understatement. But I think sainthood is taking it just a pinch too far (helping a client design a great house is my job). And Gordon I think you are right that it is both an exercise in pioneering and lunacy (to a certain degree) but I disagree with the reason that after all, “…It’s a HOUSE”

    That sentence, that sentiment, is exactly what Roger has set out to battle. I’m sure the idea of just picking a window to be done with it, entered his mind. I can attest that both my client and I have felt varying levels of exasperation through this window process, but I’m very proud of my client’s undaunted progression. I’ve been kind of quiet regarding these blogs but want to chime in at this point on his behalf. He set out to honestly document the process, he set out to make sure ALL of our decisions were well reasoned. That it could all be explained. Will everything be perfect? No. Will everything go smoothly according to plan? Clearly not. But at no point, were we going to shrug and say, “That’s good enough, it’s only a house.”

    Not many people will go to the same level of detail, but hopefully as time progresses and the market catches up to high performance windows, they wont have to.

    Chris Briley, Architect

  8. wjrobinson | | #8

    Confirmation has come in.
    Confirmation has come in. Christopher Briley is now hereby a saint. Congratulations, and well deserved.

    May all your Easter baskets from here-on-in overflowith with dark chocolate Easter bunnies.

  9. user-1087436 | | #9

    I'm still leaning toward (b), but
    it's his house, not mine, and I'm sure it will be terrific.

  10. user-2069108 | | #10

    So, how did the Bieber windows come in relative to the Unilux with respect to costs?

  11. Roger Normand | | #11

    Lunacy confirmed
    As the author of EdgewaterHaus blog, I can confirm the sentiment on lunacy, as we lived it. No AJ, it wasn't $10K, but it wasn't trivial either. We nearly bailed on trying to achieve Passive House because of this reality show. While I felt reasonably knowledgeable about many of the construction details, I was clearly unprepared for PH quality windows decisions. I found very little web info on PH Certified windows when we began our search last spring. I thought at that time any quality triple pane window with "high" SHGC would do. Not so. In the PHPP, there is a huge difference between 0.558 (Pella) and 0.62 (Bieber we bought). Ditto for frame/glazing U-values and the more obscure frame width. I refer to it as the tyranny of three decimal place accuracy.
    To steal from a still to be completed blog, here's some lessons learned. If you want PH:
    1. Begin with a list of PH certified windows. That would have eliminated Pella and Unilux. I am heartened to learn that one of my blog readers was trying to entice North American window manufacturers to become PH certified.
    2. Go look at an installed window before you invest in a PHPP analysis. In retrospect, this is a very embarrassing personal failure. The Shuco was PH certified, had a great brochure, even better price. When we saw the window, we just didn't like it.
    3. Don't try to buy a new BMW from a Chevy dealer. A BMW offers performance; a Chevy basic transportation. Don't waste your time with any window sales rep who is not conversant about PH and PHPP.
    4. When you are in a hole, stop digging. We should have pulled the plug on Unilux much sooner.
    In response to Steve Young, the Bieber price, performance and features were all better than Unilux. And our Beiber sales rep was knowledgeable, professional, responsive, and very helpful....particularly when we encountered turbulence described in the most recent GBA re-posting of our windows saga.

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