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Community and Q&A

American-made Passivhaus-certified windows

pitt2004 | Posted in PassivHaus on

Hello All,
I am posting in regards to the availability of American made Passive House windows for the U.S market. We are a small window/door manufacture in the Midwest mainly focused on energy efficient European designs. We have been building wooden German style Tilt/Turn windows, Lift/Slide doors, Entrance doors, Fold & Slide doors as well as custom entrances. Currently we manufacture our products in three thicknesses 68, 78, 92 mm however we do not offer a window that has been certified by the German or U.S. Passive House organizations. We have been tossing the idea around for some time now that maybe we should obtain these certifications and offer a wood euro style door and window to the U.S. We are aware that most individuals looking for such products are importing these due to the fact there are no local sources for these products, however there could be, we have products that are very close performance wise and with a little tweaking we could easily be where we need to be to compete with our European competitors.
We realize there may be a potential market for these products, we are just a little uneasy regarding these types of products due to the cost of components, labor and whether or not builders would be willing to accept this reality and purchase locally. Isn’t one of the goals of building green finding local sources for products and materials?
Below are a series of questions we would like any and all feedback for those willing to share their thoughts and insight.
Let’s ask the questions:
1. What features would you like to see in your ideal window? (obvious we cannot satisfy everyone’s needs)
2. What features are an absolute must?
3. Would you be willing to work with a small local manufacture if he was flexible enough to provide the product & service YOU are looking for? This is very popular in Europe where there are thousands of small window/door manufactures.
4. Would it make sense to have Window units certified for multiple NA climate zones? Or focus on the climate zones where most of the Passive construction is concentrated?
5. Regarding exterior finishes/cladding. Solid wood with Exterior rated finishes/paints or Alum. Clad shells?
6. Ability to specify your glass options based on facing direction and solar heat gain goals, how important is this? Is this a difficult request with the European or Canadian companies?
7. Lead times…what are realistic lead times acceptable to most, realizing that all projects are different?
8. Gas filling of insulated glass units: The simple fact that any change in elevation less than or greater than 1,500 ft. from where the sealed unit is manufactured and its final destination leads to installed breather tubes and in many cases for proper glazing these unit must be glazed at the job site. Is this an acceptable practice? So many times we are unable to provide inert gas fills due to elevation challenges.
9. Insect Screens? YES or NO. Fixed or roller?
10. Integrated Exterior Shading systems, Roller shutters, blinds, etc.?
11. Is there a need for a wood or wood/clad entrance door system? What are we looking for?
Thank you all for your time and consideration.
Bob Holloway
Advantage Architectural Woodwork

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  1. STEPHEN SHEEHY | | #1

    Bob- we're in the early stages of construction of our new house in Maine, zone 6. We expect to take delivery of a house full of UPVC Intus windows and doors in a few weeks. The 12 week lead time was not a problem.
    The windows were priced at about where a Marvin or Andersen would be, but are far better in terms of insulating value. To a non-engineer like me, the Intus windows and doors appear to be much beefier and have far better hardware.

    Our house will not be certified by PH or anyone else, but having P
    H certify the windows is a big plus, as I see it as a performance standard that is desireable.

    Features: we wanted casements for a porch and Intus doesn't make casements, so we bought them from Kohltech. I like the tilt turn feature very much, but for some applications, casements are preferable. Intus screens are vastly better than any I've ever seen available from US companies,which all seem like flimsy afterthought.

    High solar gain is also a plus, but I don't think you need a ton of choices.

    Don't "cheat" by calling two pieces of glass with a thin film between them a triple pane unit.

    For me, gas filled or not isn't important.

    We opted for UPVC because the performance was so good for the price. The Intus aluminium clad are nice, but the additional cost is significant, with no performance benefit.

    I would very much have preferred to buy an American window.

  2. GBA Editor
    Martin Holladay | | #2

    Alpen Windows and Marvin Windows are two U.S. window manufacturers who claim that they are now making Passivhaus-certified windows. For more information, see Marvin to Offer Passivhaus Windows.

  3. jackofalltrades777 | | #3


    What SHGC did you get on the Intus windows? Did you opt for the white or colored laminate frames?

  4. STEPHEN SHEEHY | | #4

    Peter- the SHGC was 0.494. We opted for white, except for the front entry door. There was a 25% upcharge for the colored frames and we were fine with white, as our trim will be white.
    A big reason for selecting Intus, as opposed to another vendor, was that we have a local dealer in Portland ME, Maine Green Building Supply, which was recommended by our architect.

  5. RZR | | #5

    "The heat transfer coefficient Uw has to comply with the European standard and be less than or equal to 0.8 W/m2K. Every window with an Uw-value less than or equal to 0.8 W/m2K is therefore a passive house window and suitable for installation in passive houses and is eligible for support through corresponding programs."

    Claims? Who regulates Quality Control and Assurance to this standard in Europe exported products to the US, and US production? Also, same for SHGC? When I say QC I mean who is validating the test standard? From what I understand there are different ways to calculated these parameters, requiring test simulation and third party verification's that set the assemble line configuration and monitor it?. Here are a few in the US under "code and standards":

    I see Intus is making some claims about being hurricane resistant but yet I found no ballistic test videos on there website like this?

    If I were a window-door manufacture yes u-value I can see the test results on your website and validate are important. Might want to also have a vision of the regional market. In the midwest tornado's, wind and hail. We replace PVC, wood, and aluminum clad, every year from sun, wind, hail, temp cycle, damage, it doesn't last. Our clients don't ask "can you please put in a new Passivhus certified window or door" or have any idea what SHGC or low e is" What will sustain in Germany and win marketing hype to sell homes may not here. Try carbon fiber with a kevlar or two outer plys and show me a ballistic prove test to sustain 200-250+ winds, golf ball hail, and debris like 2x4s and corrugated steel flying around that happens every year and seems to be getting worse. Texas tech has some good test videos on mass concrete walls. Check out Moore, OK, Joplin, AR, Greensburg, KS and lately Piger, NE, and the windows that blew out killing and injuring many people, concrete walls fine. Do you think people value their lives less than energy? Forget passivhaus, put money in total performance that fits the regional needs. Most have no idea what passivhaus means in the midwest, most could care less. The winner builder will need to show safety and sustainability, utility bills are last since most are low in the midwest, thats is all clients will care about. There just is not enough saving's and pay back for windows/doors that are energy efficient only, and alot of the window performance depends on other design features of the home like mass effect. I for one builder will not be getting 15 different certifications and rating's for marketing hype, rather, I will look closely and at what products I am putting into my home that effect performance and my bottom line.

  6. jackofalltrades777 | | #6

    Terry Lee,

    You stated, "I see Intus is making some claims about being hurricane resistant but yet I found no ballistic test videos on there website like this?" Intus Windows has the certification numbers listed on their site. It states:

    Intus Windows and its Eforte Series uPVC window line now meet those criteria through the ASTM F 1642-04 and GSA-TS01-2003 testing specifications. The Intus Windows line of uPVC windows and doors have been tested and meet New York State Wind-Borne Debris Region, Florida High-Velocity Hurricane Zones, and Miami-Dade County requirements.
    TAS 201-94 – Impact Test Procedures as required by Section 1625 of the Florida Building Code
    TAS 202-94 – Criteria for Testing Impact and Non-Impact Resistant Building Envelope Components Using Uniform Static Air Pressure Test
    TAS 203-94 – Criteria for Testing Products Subject to Cyclic Wind Pressure Loading Test Required by FBC and TAS 201-94
    ASTM E1886-05 – Standard Test Method for Performance of Exterior Windows, Curtain Walls, Doors and Storm Shutters Impacted by Missile(s) and Exposed to Cyclic Pressure Differentials
    ASTM E19966 – Standard Specification for Performance of Exterior Windows, Glazed Curtain Walls, Doors and Storm Shutters Impacted by Wind-Borne Debris and Hurricanes

    So one can request hurricane rated Intus' triple pane uPVC window. They have the US certifications and classifications.

  7. RZR | | #7

    Peter, I have worked as a Design and Manufacturing Engineering for manufactures for a VERY long time, and MANY standards. The Quality Control audits of adherence and compliance to test standards requires a third party. Sometimes a lab, other times an OEM (Original Equipment Manufacturer ) or end product company since there can be many suppliers. Usually the OEM conducts the QC which involves the initial prototype inspections of their supply chain to set a configuration for production to a set of standards, requirement documents, engineering drawings, etc, the manufacture has to prove compliance with. Once set, the manufacture has to report any changes to the OEM, or client, lab, or third party. Often, this requires random OEM visits the manufacture agrees to since they have nothing to hide. I have been a part of those QC inspections and audits, where the manufacture is showing compliance to test standards and my Engineering drawing's since I have worked for large OEMs. Smaller OEMs are not exempt unless one does not care about QC.

    Not sure about TAS and Florida, ASTM writes the test standard but DOES NOT Quality Control it, or Quality Assure it to the end user. A manufacture can therefore state compliance but not be held accountable, which I believe is wrong! They should be held accountable by ASTM or some third party if they are going use ASTM as a claim. You would see QC compliance docs listed on their website and the agency that "stamped" off the production line and test.

    Check out this door video:

    If they have nothing to hide why not show a video of the test and what third party conducted it, QC it, so we can call and get the specifics? Makes you wonder what else they are hiding since I see no third parties listed to call and check out how they complied with their u and shgc. In order to compare these values to other OEMs would require they use the same test and QC compliance methods.

    I'd be especially skeptical when it comes to QC of exports. I was involved with a recent program that shipped in parts from all over the globe, as part of this new "global economy" we are in that were a complete disaster. It is best to buy American provided the same QC standards. Our standards and QC of them are usually higher than most(not all) other countries, not always depending on the product, but usually. Also, we can call here domestically to learn about credibility we may not understand from other countries. I think we are realizing some of this with the topic at hand, PHPP, and rewriting it as an American Standard, although as I said we have a different environment here in the states than Germany does. We have PLENTY of standards here in the USA, that is not the issue, QC and QA is.

  8. STEPHEN SHEEHY | | #8

    Terry- I'd be interested in knowing the basis for your assertion that the US has higher standards than other countries. I believe that the EU standards for windows is likely to be more stringent than here.

  9. RZR | | #9

    Stephen, it comes from decades of experience dealing with suppliers across the globe and more global standards like ISO. Besides the point I am making, standards are no good unless they are Quality Controlled with proof of compliance. Mixing standards from different countries when comparing OEMs specs can get confusing and misleading unless an international standard is adopted and enforced.

  10. user-3549882 | | #10

    Bob asks for "any & all feedback": Referring to the numbered questions: (W = want; M = must)

    Some ideas:

    Q1,2: a) M seal fenestration opening yet open for ventilation. b) M Glass must be distortion free with clear view. c) M Cleanable. d) W Last as long as roof. e) W Features customized to the climate and position on the house, esp. designed to fit with strategy for maximizing solar gain in winter & minimizing shgc in summer. f) W Insulation value approaches surrounding walls. g) W Appearance a WOW inside and out. h) W Consistent quality & interchangeability. i) W a window doesn't need to be perfect. It should be economically justifiable.
    Q3: Economic issue.
    Q4: Economic issue.
    Q5: Finishes offered is a business decision.
    Q6: Specifying glass is very important to maximizing the energy efficiency of the window. Value of this varies by customer. Efficiency depends not only on the location on the house but also the strategy for item 1e above. Example: Landscaping? Window attachments to be used interior/exterior? Roof overhangs? Window count & layout?
    Q7: No input.
    Q8: Gas filling not critical. I've had Anderson argon-filled double panes drilled & vented to become air filled, all on Anderson's recommendation & field service.
    Q9: Insect screen is required but is critical on only a few locations in the house.
    Q10: See Q6.
    Q11: No input.

    General comments:
    - I like the tilt/turn design and have some experience with them in Europe. Why not more in the U.S.?
    - Our house has over 80 windows: a) Only 10 used for ventilation. b) 37 are selected for seasonal exterior mounted solar grates to reduce electricity for air conditioning. c) Only 14 are important "for the view". d) About 23 are fixed (non-opening). e) Over 30 have interior acrylic inserts to increase U value. f) The mix is about 90% Anderson, 10% Pella.
    - Most of Bob's questions pertain to new construction. Our house was already built.
    - I'd stay plugged into the research going on at LBNL. They have a new testing facility (Flexlab). They can quantify the effectiveness of existing designs and prototypes. Some of their work could redefine a window from passive to active and flexible.

  11. RZR | | #11

    Here I was checking out NAFS and found what I like to see as QC...AAMA Quality Controls the OEM assy line, look for their certification label. You'd be surprised what can happen between a lab test and the assembly line especially when nobody is watching. AAMA also has some stiff regulations for different climates we see in the USA, not Germany. I see lab testing on Intus web site but no third party verification on monitoring from a US agency to US standards, that account for some of the rating seen here:

    We in the midwest need higher wind and hail rating's, west more sun, east colder climates, etc...You'd also see that a lab can only simulate so much of the vast array of climate zones we see in the USA, further field and installation test are required per region that should be on the manufactures website. Again, I'm not interested here in German or European standards, we don't live there. We also have codes such as 2012 IRC, IBC, IECC Germany does not have that restrict u-values and shgc that may not work with PH. Check out this thread:

    If the manufactured designed to wind, hail, solar, temperature cycles, you would see wind and hail cycle test I have been involved in, also temperature and pressure, flex, see where the glass, wood, PVC, clad failed since the lab would take it all to failure. You see then what we see lots of failures we replace every year for clients. You'd also see how long u value and coatings last depending on how they are obtained. You'd see what design approach yields the most sustainable r-values and shgc. If you want to take over European sales hype raise the bar.

    -The manufacturer has certified that production line units are built to the same specifications as the sample unit that was tested.

    -Manufacturing plant production lines, component inventory and quality control records are checked annually through two surprise inspections by an independent third-party Validator

    Interesting how PG&E is getting into the 'building envelope' business and hiring FLEXLAB seeing how the CA solar boom is putting the power plants out of business. People that are on the grid are paying high penalties, especially peak time.

    Another one to watch NET soon our windows will be PV cellls.....

  12. jackofalltrades777 | | #12

    Terry Lee,

    I currently have AAMA certified windows that were manufactured in the USA. Sadly, they are junk and I have had 7 windows fail within the first 3 years of installing them. I am not alone. All the AAMA windows in the area have failed and are having problems.

    There are no guarantees in life and having a 3rd party certify something doesn't guarantee anything. Quality Control in US made windows is all over the board. Some are good and some are really bad, even though they all may get AAMA certification. So I disagree with your position about AAMA and in regards to QC for US made windows.

    Even "lifetime warranties" on US made windows are a joke. Go and do a web search on Pella, Marvin, Milgard, Anderson, etc. and see how many people got ripped off when their windows failed and the "warranty" proved to be a joke. The warranty clause has so much fine print written-in by the lawyers that it is next to impossible for the average homeowner to try and litigate it.

  13. RZR | | #13

    Peter L wrote: I currently have AAMA certified windows that were manufactured in the USA. Sadly, they are junk and I have had 7 windows fail within the first 3 years of installing them. I am not alone. All the AAMA windows in the area have failed and are having problems.

    Peter, can you be more specific. What AAMA certified manufactures? What failures?

  14. jackofalltrades777 | | #14

    Terry Lee,

    Here is the worthless AAMA sticker still hanging from the top of the window:

    They are Milgard Windows and as far as failures go, where to begin?
    1 - The seal between the window frame and window glazing has failed numerous times and allowed water to enter in and damage the drywall window sill.
    2 - In light rains the water pools onto the track of the sliders and begins to overflow and spill onto the window sill.
    3 - The exterior vinyl has twisted and warped and began to chalk.
    4 - In light winds the operable windows whistle between the operable glazing and let in dust and dirt.

    I can go on and on but the point of all of this is to show you that certifications from the AAMA means nothing. I am not alone in these window woes. Numerous homeowners have experienced the same problems with these AAMA certified windows. High-Quality European windows don't need an AAMA certification, while low-quality windows like the ones on this home have the AAMA certification.

  15. jj1 | | #15

    Dear W D: you mention you have "Over 30" windows which "have interior acrylic inserts to increase U value". Kindly describe these inserts. Are they transparent? How much U or R value do they add to the insulating property of the window? What brand name(s), where could one buy them?

  16. user-3549882 | | #16

    Jan, (response to Jan Jaran)

    The interior acrylic inserts come from transparent acrylic sheet. It looks just like glass. I first examine the (casement) windows and the window framing. The acrylic is cut to fit into the framing recesses. I attach a non-descript furniture knob near the acrylic top for removal and cleaning. Color matched toggle screws are used to hold the acrylic in place (4-6 does the job). It's not a seal but it's still functional. You see the screws but you don't notice them. I have to point out to people that there's something inboard of the window. Acrylics are not used where the windows are used for ventilation. There's a practical limit to the size of these sheets. I'd say about 2' x 5' max. I have no measure of the U value. The U value is there, however, as I could pick up the temperature difference with a non-contact laser meter (but I don't have the data documented for easy recovery).

    I'd say pick a window and try it if it interests you. This way all of your questions will be answered with little $ at risk. I bought all my acrylic and hardware at Menards but Home Depot has similar stuff. The largest sheets available are 4' x 8' and this is what I usually bought and cut to size.

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