Thermal window coverings: Got Ideas?
I’m designing a super-insulated home for a view lot.
It’s going to have six large areas of fixed glass, 4X6 to 4X12.
The walls will be about 9″ deep.
Of course the R value for glass, even triple insulated, is very poor so I’m trying to imagine how to provide better insulated cover for the fixed glass areas during winter nights.
Right now I’m fixed on shutters, made out of SIPs. They could be quite thick because the glass can be placed on the inner or outer margin of the opening. Installed on hinges like a door, the shutters would fit snugly in the opening, using a latch to hold them in place.
Have you seen anything like this? Maybe in a magazine?
Do you see any weaknesses in this concept? How would you improve it?
Got any other ideas on how to mitigate the poor insulating qualities of glass?
Replies
Sounds okay to me, though I don't know what you mean about glass being placed on inner or outer margin of the opening. Oh, like inset deep in wall from outside or closer to surface on outside?
Back in the 70's-80's, I got a book out of the library about insulating curtains, drapes and shutters for windows. It had lots of ideas--like foam panels covered with fabric that fit inside windows--maybe had Velcro. Insulating, thick drapes, I think they were hung on a pole with another pole through a seam at the bottom and then you could pick the bottom pole up and set in on pegs either side of the window at various levels or leave it hang entirely (is a name for such shades--"Roman shades" or some name like that).
The other popular shade back then was a quilted shade that retracted onto a roller at the top of the window and ran in guides down the sides, so it was well sealed. The quilting was just that, two sheets of fabric with batting in between sewn as a quilt. It was about 3/16" thick. Seemed quite effective.
Panels like you describe don't seem worth the trouble.
I had similar ideas about outside close able shutters but ran into problems with the idea.
1. Tight seal difficult to obtain
2. Manually going out every evening and closing them (pita)
3. Wind ripping them off the wall.
There is (if cost is no object) metal security shutters from Europe that can be motorized and some may have a layer of foam inside them. Connected to a photo cell and the home electronics would be able to close some or all at dusk automatically.
On a ICF home it would be practically bomb proof.
Jim
I had similar ideas about outside close able shutters but ran into problems with the idea.
1. Tight seal difficult to obtain
2. Manually going out every evening and closing them (pita)
3. Wind ripping them off the wall.
Thanks for letting me know about those problems. I'd pretty much dismissed the idea of installing them outside, mainly because my house will be three stories.
Putting them inside and making them part of the decor would make them easier to deal with. Might even hinge them on top, if I can come up with a simple way to raise them.
Talisker -- in Europe, they have shutters on the outside on every window -- they are built in and operate from the inside manually or automatically (can be on timers too) -- they are called Rolladen -- they work great -- so if this house has not been built, it is an excellent ways to seal the outside out http://www.rolladenlv.com/
Dudley, thanks for the link. I had heard of them from a coworker. I suspect that I will not be able to budget them in the house at this time. However my daughter wants me to general her new home in a couple of years and having lived in England for several years wants the roll up units in her home.
Jim
i was thinking low-tech, low maintenance.....
eg : take a typical 400 series Anderson DHcomes with an external , full screen
in the heating season, take out the full screen & insert a single piece of polycarb or Lexonitewith no other improvements, it would take care of wind-washing, there would wtill be some minor edge loss, and the space would vary from say 1"+ at the top sash to 3" at teh bottom sash3/4 would be ideal, overall... but this would still be a major improvement.... in the Spring, remove, store & replace the screenseach could be numbered in one of the corners... just like the old wooden storms ( which were very effective, but a huge maintenance issue )Mike Smith Rhode Island : Design / Build / Repair / Restore
in the heating season, take out the full screen & insert a single piece of polycarb or Lexonite
I'm guessing that you're talking about Lexan or something similar. I suppose that would work OK on modest sized windows but it's probably too flexible for big openings, like what I have in mind for my next home.
At the cottage in NH, we converted a covered porch to living space. Four windows (sliders) were added, each somewhere around 4 feet wide. Double pane glass, and insect screens were provided. First winter in use, we'd get condensation on the glass in the coldest weather. I had some glass storms made up, same size as the screen frames. No more condensation.For a couple of original sliders, maybe 5 feet wide each, the storms were made up in two pieces, joined in the center by a vertical H bar of aluminum. I had to rig the thing a bit for support top and bottom, as well as at the outside corners of the whole window.A word of caution about using glass for this. The stuff they used was not safety glass. In a brief moment of inattention while removing them one spring, I turned my back on one after removing the clips at the corners. The thing fell over, breaking on my head. Looking at the shards lying on the ground, I figured I was lucky one of the larger pieces didn't slice through the carotid artery on my neck.
what's a big opening ?
if you keep the individual lights at 34 x 76, you can buy standardized insulated glass units
and you can mull those until the cows come home
bigger units have problems with oil-canningMike Smith Rhode Island : Design / Build / Repair / Restore
mulling that over....<G>
Hadn't thought about standard sized insulated units, cause I've always order insulated glass to fit an opening. That makes them more directly competitive, in addition to being more easily and readily available.
I shall investigate that further. Thanks, Mike.
I have been thinking about insulated roll-up shutters for a while. The rollup shutters are primarily targeted at security or hurricane protection. In my case, I am planning on building in a area with periodic wildfires, so I am primarily interested in fire protection. However, there are also insulated versions of these shutters, although I am not sure what R value they give. The shutters I have looked at are primarily an interlocking aluminum design and generally are raised and lowered by motors. The one that I had the most detailed drawings on show them housed in a box that is 8"x8" by the length of the shutter. The box would then either be attached to the side of the house above the window where it would be visible or hidden in a soffit above the window. A Google search on "insulated roll-up shutters" will give a number of vendors. There was also an article in the S.F. Chronicle some time back about building your own insulated shutters. I believe these were hinged foam core wooden panels rather than the roll up type I mentioned above.http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2008/01/19/HO7VU024E.DTL
There was also an article in the S.F. Chronicle some time back about building your own insulated shutters. I believe these were hinged foam core wooden panels rather than the roll up type I mentioned above.
http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2008/01/19/HO7VU024E.DTL
Ah...bifolds, nice design too. Thanks for that link. That's the kind of thing I'd hoped that someone, like you, would have to share on the subject.
FWIW: there's a round icon at the top of the text in the above linked article which is a link to the drawings.
It's not just nighttime heat loss you've got to be concerned about. If those windows are facing south, east or west, you could have a significant overheating problem without a lot of additional direct-gain thermal mass.
South facing windows beyond 7% of floor area require 6 sf of 4" thick masonry per square foot for direct gain mass.
The problem with shutters is where do they rest when they're open? If inside, they take up wall space and limit furniture placement. If outside, they're difficult to use and vulnerable to weather.
The two brands of insulated window quilts were Window Quilts and Comfort Shades (the latter was made right here in Warren VT by my friend and neighbor).
View Image View Image
The Comfort Shade had weatherstripped channels which sealed the sides of the multi-layered radiant-barrier shade as it closed, and operated by a continuous chain.
Solar & Super-Insulated Healthy Homes
Edited 3/26/2008 10:36 am ET by Riversong
Be carefull with all of the things metioned here. These products will cause less heat to get to the interior surface of the glass. This will cause more condensation and possible mold and wood rot. And since there will be little air movement, the water will be there for a while and not allowed to evaporate. IMHO.
"It is what it is."
It's not just nighttime heat loss you've got to be concerned about. If those windows are facing south, east or west, you could have a significant overheating problem without a lot of additional direct-gain thermal mass.
I've lived with that problem, several times. I plan on shading the glass externally with long roof overhangs, porch roofs or custom built awnings (see photo file).
The problem with shutters is where to they rest when they're open? If inside, they take up wall space and limit furniture placement.
I'm considering how to make them part of the interior decor. I'd prefer hinging them on top and raising them to the ceiling. A pulley system would work but it'll need some practical engineering.
Thanks for the info about the quilts and shades. Do you have any data on how effective they are?
I've seen interior 'shutters' that fold upwards - hinge them at the top and about the center, pull on the rope, the center hinge kicks inward and the bottom edge goes up - man....that pict is in some '70's book/literature/publication - I can see it in my minds eye, but can't remember where - very simple and as elegant as such a system can be...pulley system was the key - I'll think about it, maybe I can dredge it up...."there's enough for everyone"
I've seen interior 'shutters' that fold upwards - hinge them at the top and about the center, pull on the rope, the center hinge kicks inward and the bottom edge goes up -
That sounds pretty ideal, something like the bi-fold system linked in a previous post from CaseyR.
Edited 3/25/2008 11:40 pm by Hudson Valley Carpenter
Do you have any data on how effective they are?
According to the manufacturer, Window Quilts with a lowE IG unit will give a total R-7.14. The Comfort Shade is not presently in production.
http://www.1windowquilts.com/rvalue.html#chart
Another Vermont-made option is a double cellular polyester tracked shade, either room-darkening or light-filtering (which makes them useful to reduce summer sun), that offers an additional R-3 beyond the window value.
http://cellularwindowshades.com/rvalue.html
Riversong HouseWright
Design * * Build * * Renovate * * ConsultSolar & Super-Insulated Healthy Homes
Hi,
There are a bunch of inside window treatments from primitive to fancy listed here:
http://www.builditsolar.com/Projects/Conservation/conservation.htm#WindowTreatments
We have been using these cellular shades with an "energy track" to reduce air leakage around the sides since 2000 -- like them a lot:
http://www.builditsolar.com/References/Half/ProjectsConservation.htm#Shades
The claim is R4.3 over the regular window -- if I am recalling correctly this is backed up with some sort of independent testing -- pretty impressive. They have held up to 8 years of up and down every day, but are beginning to show some signs of age.
You might want to pick up a copy of the book "Thermal Shutters and Shades", William Shurcliff
Its an 80's book on dozens and dozens of shutter and shade configurations. Shurcliff was a good physicist, so the book is both practical and analytical -- here is the a little from it:
http://www.builditsolar.com/Projects/Conservation/ThermalShades/Shurcliff%20Thermal%20Shades.htm
Last time I looked its still available used on Amazon and the like.
Gary
Gary,
I finally found time to check out those sites you suggested and linked in your post. There's some very interesting and valuable information there. It's always helpful to see what others have tried and how it's worked for them.
Thanks for taking the time to put that post together. I'm sure to benefit from it as I work on my own solution to that problem.
Peter
Be carefull where you put the panels and how well you seal them. I've seen panels put on the inside of a window that created a dew point in between the glass ond the panel. All the windows had water damage on the inside. Of coarse it was poorly done and they didn't have a clue what they were doing.
Storm windows are put on the outside and there is some ventalation behind them depending on how much moisture is in the house and how well the window stops it.
Whatever you do remeber to take a look at it next winter when it gets real cold for a while. Just to make sure.
Edited 3/27/2008 9:08 am ET by popawheelie
Thermal window coverings: Got Ideas?
If you’re opting for shutters, make it Western Red Cedar. A bit pricey but all worth it. Because of its structural stability, panels can be made wider or taller without the need for a midrail. It is lightweight, and has excellent thermal and acoustic properties.