Passive House Doors with and without Windows

Passive House Doors with and without Windows/Glazings

While I have been focusing primarily on energy efficient passive house windows, we also have to consider passive house doors in much the same manner.  The same principles of energy efficiency and airtightness for windows applies equally to doors.

To be clear, using specific doors or windows in a Passive House project doesn't, in and of itself, make them passive house doors or passive house windows.  They would have to be rated or certified to be so, by PHI, as some are (such as Pazen), or at the very least provide similar performance characteristics to those that have been.

Fortunately, the overall energy performance of a building is an amalgamation of many performance characteristics and the approach taken, holistic.  This is the beauty of the PHPP program and how thoroughly so may details have been considered and modeled mathematically to suggest what can be used and in predicting the result.

One of the reasons we selected Loewen, was because they had a local presence (retailer) which allowed us to actually see the windows and doors in person.  Had other higher performing manufacturers operated locations in our area, at the time, we may have considered more brands.  Fortunately, as time has elapsed since our construction, higher energy efficient window manufacturers from abroad are becoming more readily accessible in the U.S.  I think it important to actually be able to personally see and handle them prior to purchase.  Also having the support needed in the area, in the event any issues prop-up are of utmost importance.  (Related article to follow on this very subject).

Another reason we selected Loewen, beyond their sheer architectural beauty and performance, was because they manufacture both energy efficient windows and doors.  We decided we wanted to keep a certain consistency and continuity, architecturally, to our window and doors.

The exception to this was the use of Therma-Tru doors for the front main foyer entrance, utility/mud-room, garage (which needed to be fire-rated), and pet-room (located in our basement).

In the case of these doors we minimized the use of or completely eliminated window glazings.  We did not opt for "exotic" doors with extremely high performance ratings.  Given the relatively limited amount of square footage allocated to these doors, coupled with the fact that we minimized window usage in them, we found their thermal insulating performance to be adequate.  We did focus heavily on making sure these doors were as airtight as possible, using additional stripping/sealing when it was required and then tested for air-leakage before and after.


I have to admit it: we selected three double slider door units!  And they were placed on the North facing side.  Here I have broken two "cardinal" sins of passive house design.  Oops!

Why did we do this?  For aesthetics, appeal, and natural light, of course!

That and the fact that Loewen rated their sliders highly--especially when it came to airtightness.

Conventional wisdom would suggest that there is no way that one can produce an "airtight" slider door (essentially a large double-hung window turned on its side).  However, Loewen has done just that.  To be sure, are these door configurations optimal?  Not likely.  A single swing door would have been more so.

But again, my wife and I were striving, first and foremost, for livability.  This project was not merely an exercise in science and engineering--we didn't want to live in a shoebox--we wanted a conventionally appearing home as much as we could.

Passive House Door?  Very good, but not perfect:  Slight Air Leak Visible Under Pressure, Prior to Additional Sealing

The views out of the back of the house are wonderful and we didn't want to compromise that view or our accessibility to the back of our property for just the sake of achieving the lowest possible SSHD number.

Interestingly enough, Loewen rates their slider doors more highly than their french double-door configuration.

Loewen's engineering was also a pleasure to work with.  They fabricated, for the first time specifically for our project, a triple-pane swing door.  Up to that time, Loewen had only manufactured twin-pane swing doors.  The concern by engineering had been the reduction of inter-glass spacing with a triple-pane configuration versus a double-pane configuration in a relatively thin frame of a swing door.  As it turned out, their energy modeling algorithm demonstrated that a triple-pane configuration would perform as least as well, as it was engineered, so we gave them the go ahead to specifically construct them for us.

I was most impressed with Loewen's commitment to our project and their interest in engineering and producing windows and doors specifically tailored to the Passive House community.  I believe this project was a learning experience for both of us and I hope for even more impressive products from them in the future, as a consequence.


  1. Thanks for the great detailed descriptions of passive house window characteristics. It is also interesting to hear about how many ph rules you bent. You are braver than we are...but we will be building our house into a hill and the view out the north side is not impressive in the least so we will be adhering to the north side rules...and most other rules for that matter. Anyway, now I'm really looking forward to reading more of your future posts!

  2. You are certainly welcome, Mimi.

    We didn't make these decisions of bending "rules" arbitrarily. We relied on PHPP modeling to determine what we could get away with. Choices like relatively complex building shape, larger amount of north side glazings, cantilevered balconies, and use of some recessed lighting in the ceiling leading to the attic space, did create challenges to be sure and created a lot of additional work (in some cases) to mitigate, but the end result, we believe, was worth it.

    To walk into our home, you wouldn't necessarily be aware of all that is going one as it relates to PH. The house doesn't look "strange." Just ordinary, which is the way we wanted it.

    Lisa and I look forward to reading about your project and hope you blog your experiences, as well!

  3. It's exciting to see how passive house is moving in directions that will encourage more people to think about the possibility of building this way. When we first started looking at passive houses we were concerned with the lack of "affordable" and "attractive" options that seemed to be the norm with PH architecture. Our goal is to build an attractive, affordable average sized home that is low maintenance and a joy to live in. I have been blogging about our experience. We have done the excavation but are still working with the architect to finalize the design. If you're interested you can catch our follies at
    Thanks for your quick replies to my comments.

  4. Bob,

    Where did you source your Loewen PHPP window performance data?



  5. Our window selection was made with the assistance of Loewen's engineering group. Prior to our order, they were willing to experiment with some new glazing combinations from their supplier(s) to achieve certain U-value and SHGC value performance design specifications we were seeking. Although we didn't specifically choose (what would have been) novel (truly customized) materials, we were able to sufficiently accomplish our objective with their existing offerings through our holistic approach.


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