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Community and Q&A

Operable exterior thermal shutters

Andrew Robinson | Posted in Energy Efficiency and Durability on


We are building a duplex in Yellowknife, Canada – climate zone 8 (design temp minus 45 – same as Fairbanks).

Our winters are long and dark so some sort of (external) insulated window shutter is a huge energy saving opportunity. Our walls are going to R50, while triple pane windows get about R4.

I’m thinking of using 2-3 inches of Roxul board sandwiched between wood. That could give up to R12.

Problem is to be able to open & close the external shutters without opening the windows. Non-thermal shutters (or shutters with very low R-values) are common in Europe & I’ve found some manufacturers of handles that open the shutters from the inside:




1 – does anybody import or make anything like this in North America?

2 – I imagine the French example could be adapted to use standard window opening hardware like this: Anyone ever tried this?


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  1. GBA Editor
    Martin Holladay | | #1

    Thorsten Chlupp is the King of Exterior Thermal Shutters. As far as I know, his shutters where site-built.

    More information -- but probably not enough information to satisfy you -- can be found in his PowerPoint presentation here.

    I'll post two of his slides below. (Click on an image to enlarge it.)


  2. Jin Kazama | | #2

    Funny to see the difference in design from "les francais" then the deutsch . :)

    I have been tinkering with a product idea for this purpose for some time,
    but lately haven't been able to focus on it to complete a possible design.

    I will need a thermal shutter for a few near future projects, and as you,found out no suitable products for our cold climate.

    A few points...

    If your windows are recessed and have an exterior flashing box, it will be easier and more aesthetically correct to use a thicker insulation panel.

    Even an R3-4 1" EPS/XPS board would make a good difference, i do not believe that going over R8 would be possible to justify.

    One could use sunshades with motorization that would change position during winter from open during the day to close after midnight etc.. being used stationary as a sunshade during summer time.

    Could even design it to work using insulated backed PV panels .

    The german/french products you linked could be used to drive a panel that would sit between 2 bearings in the vertical axe ( or a bearing at the bottom and a bushing up top ).

    Some other products use in wall or top of window roller shades.
    This one is made out of insulated aluminum profile
    ( they happen to manufacture the alum windows i like the most out of EU )

    Most motorized exterior products of quality use "somfy " motors and controls
    ( french brand ) and they can be easily purchased online by anyone if you dare DIY on your project.
    Pretty cheap but reliable stuff.

    You could then have the motor at the exterior directly driving the shutter itself
    ( u either install it inside the shutter or at the pivot point on the walls )
    and you would only have to provide with ac or dc power
    ( they are wireless and can be fully programmed )

    When designing this, think about snow accumulation on the border of the window !

  3. Jin Kazama | | #3

    MArtin : had forgotten about him ahah ..been a while last time i heard about his house.

    He used hangar style ( we call it " porte de grange " locally ) hardware to hang the shutters.
    If i recall correctly he closes them by hand ?

    could be automated easily with the help of some cables/pulleys and the same somfy motors.

    R20 !! :)

    Between, using EPS/XPS boards instead of Roxul batts could give you the opportunity of gluing the thing altogether to get somewhat of a stiffening attribute
    ( similar phenomen to SIP panels ) where batts would not .

  4. Expert Member
    Malcolm Taylor | | #4

    Here is a link to a FHB article on an Alaskan house where the owner made site built shutters.

  5. GBA Editor
    Martin Holladay | | #5

    Yes, that's a relevant article. It's another example from Fairbanks, Alaska.


  6. Jeff Stern | | #6

    R4 windows are really not very good considering your climate. In addition to the shutters, I would suggest using a much better performing window.

  7. Andrew Robinson | | #7

    Martin: Thanks for the links to Thorsten's projects in Alaska - he is my inspiration to try and take this to the next level.

    I have talked to him about this a few months ago & he had recently tried framing in interior sliding shutters - which did not air-seal well enough -with predictable results.

    Hence my "return" to Europe & the time tested hinged, external shutter.


  8. Andrew Robinson | | #8

    Jeff Stern: I would very much like to know about windows with a rating greater than R4. Even more so if they have a solar heat gain coefficient greater than 0.5.

    I wonder if we use the same method of measuring R or U -value for windows? I'm basing my estimate on Canada's HOT2000 software that calculates the effective R-value, including losses through the frame.

    Can't get triple pane, argon filled, double low-e coating with insulated spacer windows to model above R-4.

    Perhaps that is a discussion for another thread.


  9. Andrew Robinson | | #9

    Jin Kazama:

    Thanks for the suggestions. In general I'm looking for something that lets in every ray of sunshine during the day but provides high insulation levels at night. Our climate does not have any overheating issues (yet).

    The shutter R-value that can be "justified" naturally depends on the climate. At minus 45 you'll find your self justifying many things!

    kind regards


  10. Jerry Liebler | | #10

    Some pleated shades claim to offer an added r3. Maybe two layers of pleated shades, running in tracks to get a bit better air seals certainly less painful than external shutters.

  11. Expert Member
    Malcolm Taylor | | #11

    Andrew, What i like about the example I posted above was that the shutters were considered as being more than just a way to increase the insulation at the windows, and became a prominent architectural feature. I hope you can incorporate them into your design so they act in a similar way, adding to the house's visual interest.

  12. Jeff Stern | | #12

    Andrew: I know Martin and GBA have written some fairly recent articles outlining many of the available high performing windows out there. The european imports tend to be the best performing with better glass (and most expensive), but I believe there are some very good performing fiberglass windows made in Canada. I used Zola Thermoclad Plus on my own passivhaus - roughly R-8 with .5 SHGC glass. Not only do they perform well, they are beautiful too. Good luck with your project.

  13. Jin Kazama | | #13

    Jerry: please ... R3 for pleated interior shade ... if very cheap, even if it performs only as R1 could be interesting as add on solution or to "diffuse" solar light during summer time maybe ?
    ( translucent white ones .. )

    Andrew: adding insulation to the interior of a window seems easy ...until you understand that the temperature of the interior most glass will be low, lower than the interior room dew point , and will condense . So air sealing must be perfect ( too complex )

    So the additional insulation on windows go outside.

    If you have multiple smaller windows, it would probably be easier to buy the Deutsch louver product and make your own insulated boxes .

    mr Chlupp approach is good for large windows, or multiples windows that are close together.

    Most types we've discussed so far will let all the sun rays in when open .

    I fully understand your POV about -45c :)
    Every tiny bit counts .
    We don't quite dip below -35c here, and it is already extreme.

    There is always an aesthetic solution waiting to be found.
    Keep diggind and thinking :)

  14. Ven Sonata | | #14

    Check out my my youtube film "Energy efficiency at Birken monastery" Here you will see a 10,000 sq ft building with about 1000 sq feet of windows. All the windows have external or internal insulated shutters. from r20 to r30. We built them ourselves. They have tight seals because of gaskets...think of them as an exterior door closing over a window, but from the inside. I can be done. We have huge sliding panels 8 x8, overhead closing, and side closing. The insulation is polyiso glued to birch ply framed by fir.

    1. user-7688267 | | #26

      i love your video thanks for making it!

  15. Jin Kazama | | #15

    ven sonata : was fun to watch your video

    I especially like the shutters ...both interior and exterior

    The storage room direct to earth ...

    Nice build and you seem like a very knowledge guy/monk ? :p

    I though need to point out that the polyiso you used on the exterior shutters will probably be far
    from R30 during cold winter time.
    Look for polyiso disucssions on this community for more info.

    Bonjour from eastern Canada! :)

  16. Andrew Robinson | | #16

    Ven: Nice to see others working on the same ideas, and you are not even that far from here!

    Here is the link for those who couldn't find it. Interesting, but long video. Shutters are discussed at 2:15 (interior - top hinge), 14:05 (exterior side hinge), 30:33 (interior mega-sliders) & 33:00 (exterior non-operating). Impressive - largest use of insulating windows shutters I have come across.

    At 7:19 the host mentions that the interior pane of the windows can crack if the internal shutters are not opened during the day. I have heard that this can also happen when interior shutters are opened - apparently the thermal shock from warm interior air against a window that has cooled overnight causes cracks. Any more details on this "cracking ?


  17. Andrew Robinson | | #17

    Update - here is a rough sketch of what we are planning - going with the German "through the wall" idea.

    1 - where to get a small, affordable right-angle gear box that can take a bit of wind force and also provide the right gear ratio.
    2 - will the fire code people (in Yellowknife, NT, Canada) accept that these shutters do not pose an unacceptable barrier to "egress" through bedroom windows. If so, how to include a mechanism so that they can be pushed open from the inside.
    3 - how to actually build a weather-proof, nice looking R20 shutter
    4 - Will the 5/4" Fibre Cement trim board be able to take the stress of having a little shutter operating gear box mounted on it?

    Will provide updates as these things get resolved.


  18. Aj Builder, Upstate NY Zone 6a | | #18

    I'm thinking.... cost of shutters.... verses ticket to Hawaii for the winter.

    But then I would miss my sled pups too much. Maybe Hawaiian sled pups wheels on the sled?

  19. Stephen Thwaites | | #19


    On the windows,
    1. You should be cautious about using European Window U-values because they are based on a warmer outside temperature than North American Window U-values. As you likely know, Yellowknife is extremely cold and the North American Condition is more realistic for your duplex.
    2. You should be able to find Casement Windows that are better than R-4. Several Canadian firms make High Solar Heat Gain Casements that are R-5 for your South Elevation and R-6 Windows for the other Elevations.
    3. Those same firms, with much persistence, should be able to get you the data you need to run HOT2000 in detailed window mode. This mode will get you away from its default values for spacers and frames that are keeping you mired at R-4.

    Stephen Thwaites
    Thermotech Fiberglass Fenestration

  20. Stephen Thwaites | | #20


    On the shutters,
    1. Just like windows suffer from edge losses that reduce their overall insulating ability below their centre (CDN spelling for CDN question) of glass R-value, so too will the edge of shutter area reduce the insulating value of your shutters below that of the insulation in the shutters. If you want a realistic number look at how wood framed walls are derated.
    2. Too find a North American Shutter maker than uses the European Shutter Hardware you identified in your links, contacting the European Hardware Suppliers is likely your best bet.
    3. At a glance it will difficult to use North American Casement Operators to provide the same functionality, because Casement Windows only need to open 90 degrees. I think you want your shutters to open 180 degrees.
    4. The operating shaft for the Euro Shutter Hardware does not look to be thermally broken. In Yellowknife you should be prepared for condensation or frost on the shaft and handle.
    5. If you are still keen and have both the taste and budget (especially the budget) for adventure you could end up with an exceptionally energy efficient building.

    Stephen Thwaites
    Thermotech Fiberglass Fenestration

  21. Andrew Robinson | | #21

    Stephen: Thanks for those answers on the windows - we did get a quote from a European Manufacturer that claimed R8, but weren't sure they were using North American values. Their quote was ~$40K higher than the PVC triple panes we ended up using - for 440 sq ft (29 windows) - that is almost $1,000 per window!

    I figure I can get some half decent shutters for less than $500 per window and still get better performance than a R-8 window.

    On your shutter points:

    1 - yes - the edges of the shutters will not insulate as well as the centre, but, as they are bigger than the window, the edges will overlap with our walls - should help with heat going out through the window frames

    2 - I have been working on my rusty german!

    3 - Yes - shutters need to open 180 degrees. Currently going with a gear-box idea, but there is probably a way to use a clever design to convert a 90 degree swing into 180. Leverage. Know any North American Casement operator manufacturers who might want to work on this with us?

    4 - Some of the more expensive german hardware does have a thermal break.

    But I figure that a 13 inch long handle can't be much worse than the casement operators - not much of a thermal break there either.

    5 - Yes - I'm keen & we're going to give it a shot!

    As always - any advice & constructive criticism is welcome :-)


  22. Stephen Thwaites | | #22


    On adapting casement operators from 90 to 180 degree operation;
    In my experience, Casement Operator Manufacturers need to see annual markets in the thousands before they will even make small accessories to adapt existing products to less conventional frames. My guess is you are going to have a tough time finding a mainstream firm interested in creating a whole new functionality. On the other hand a smaller production oriented machine shop might be able to help – especially considering the European shutter opoerators seem to be on the order of $450CDN per shutter, (before shipping and duty).
    You should be able to find a local window shop that can supply you with some scratch & dent casement operators for experimentation.

    On thermally broken hardware;
    I suspect most Casements in your area have a centre seal, so that the casement operators are at least one air space from the exterior. Additionally, the sash mounting plate is typically no closer than 32mm (1.25”) from the exterior. One German site showed a ?3mm? thermal break in their shutter hardware's shaft. I would say this is significantly less of a thermal break than that separating typical casment hardware from the exterior.
    You are correct though that the 13” length of the shutter drive is in your favour.

    Good luck on your adventure,
    Stephen Thwaites
    Thermotech Fiberglass Fenestration

  23. John Wulsin | | #23

    I'm replying to this ~7 year old thread in the hopes that some of the original commenters are still active. I'm curious if anything has changed in this space (thermal, operable shutters). Are there any manufacturers making something operable, thermal shutters? Or is it all still the realm of DIY?

  24. Johngfc | | #24

    Ditto - I'm also interested in anything new. The most practical we've found is Window Quilts - - which are interior and almost the same as the insulated blinds we made nearly 30 years ago. There must be advances since then, for interior blinds and exterior shutters.

  25. Scottie_Miller | | #25

    Hi John (and John), I’ve been doing some digging on this stuff and haven’t found much better info than this now somewhat dated thread. Thorsten Chlupp does have a spec for exterior thermal shutters, which I’ll try to attach here, (I’m writing from a cell phone). Thorsten is apparently in Central Asia (or something) through late 2021, and I was hoping to chat with him about his experience/details when he returns. I contacted the vacuum insulated panel manufacturer and they’re going gang busters meeting demand for portable scientific freezer demand for vaccines. They can do special orders for one off construction stuff but expect around $160 setup fee for each panel size and $35/SF. Really good stuff though. If you’re actively planning projects I’d be delighted to compare notes. Good luck!

  26. user-7688267 | | #27

    I am surpised no one has just use a 12v gear motor, photo sensor and garage door remote control along with some laser cut hinges to directly swing open the insulated panels remotely. It could open when sun comes out and close at night! This is not rocket science and maybe the energy savings are too small for anyone but environmental geeks to be interested in.

    1. Expert Member
      Malcolm Taylor | | #29

      User ...267,

      See my post #4 above.

  27. Forrest Stanley | | #28

    The most cost effective shutter solution I have ever seen is to use steel or fiberglass exterior doors as the shutter and then have the window glass sized to fit the door opening. Standard doors come insulated to R-6 and above - adding windows with R-2 or higher will get you above R-8. I have actually done this, although I mounted ours to open inward but they could also be mounted for outward opening. Standard doors have the added advantage of seals that work really well in nearly all weather, some are even magnetic. Just a thought! HAVE FUN !

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