[Greenbuilding] The beauty of STEEL FRAME WINDOWS.............?????
Jim Weiler
heavysideways at gmail.com
Fri Aug 3 12:47:58 EDT 2007
Kathy- I am in Texas, so as others I am more concerned with the
summertime heat, but the insulation process is the same, discounting
the condensation/moisture discussion currently the focus of this
conversation.
A couple of years back, I was living in a brick-walled apartment
complex, and I was disturbed by the high cost of running my 18k btu
240V A/C window unit at my apartment. A brick-and-mortar building
acts somewhat like adobe, rammed earth, etc. so I thought the
insulation properties should be better than it was. In addition, my
unit was in the middle, between other units, so only the front and
back walls were directly exposed to the sun during the day. I figured
the single-paned sash windows were the culprit.
So the solution I went for was to go for essentially double-paning to
create a dead-air layer for insulating the aluminum-framed windows. I
bought a couple of sheets of what they call 1/2" foam-core over here,
the kind that has a plastic coating on one side, aluminum foil on the
other, and 1/2" of closed-cell foam in between. I attached it
directly to the aluminum frame sash panels using 2" aluminum foil
duct insulation tape, so that the dead-air layer was about 1/2-inch.
I placed the aluminum foil side facing out for better reflection, and
painted both sides to match the interior and exterior wall paint.
Because the foam-core calls for interior safety protection (in a
fire, it produces a very bad gas), I placed the foam-core outside the
glass, so that the glass layer protects the interior from fumes.
Where I couldn't put it outside of the glass (in the openings around
the A/C unit, for example), I put sheet-metal inside. sheetrock is
also an adequate interior protection. If you choose to use any
expanded plastic foam for an indoor "insulated shutter," I would
recommend taping all exposed foam-core edges with the 2" aluminum
duct tape, as a flame retardant in case of fire, and be aware that
enough heat will defeat any retardant and bad gas will result if
plastic is present.
I've been somewhat puzzled by the "interior shutter" discussion in
regards to the thickness recommended by several contributors. It has
been said that as much as 6 layers of foam board has been used to
make these shutters, but since I was going primarily for the dead-air
effect, and considered that only 1/2" of foam-core would be superior
to a second pane of glass, for retrofitting single-pane windows, I
didn't even consider more than one layer of foam-core board. But I
would guess the temperature differential in colder climes calls for
the thicker shutters. In re: the fire-retardant problem of expanded
foam-core, it occurs to me that two layers of foam-core placed
face-to-face so that the aluminum side of each layer presents itself
to any approaching flame, coupled with the edges being covered with
the aluminum foil tape, might be the best that you could do for that
under the circumstances.
In your particular situation with the steel-frame windows, some of
the magnetic strips that come in rolls should substitute for the more
permanent taping method for ease of removal of the shutters, but I
would still seal the edges of the foam-core layer(s) itself with the
aluminum duct tape for fire safety. Trapping the air between for the
dead-air layer effect is important, so I consider a close fit to the
window frame is necessary.
The one nice thing about the aluminum duct tape is that it is usually
easily removed with no traces when you take down the shutters. The
down-side of the duct tape is that it doesn't stick well to moist
surfaces, which might not bode well for condensation and winter
conditions.
The bottom line for me is that the addition of my dead-air layers on
the windows cut my electric bills in half and my apartment stayed
more uniformly cooler than it would have been without it. I use
outside air to ventilate whenever possible, so moisture and mold is
not a problem for me.
I hope this helps you. -Jim
At 10:08 PM -0700 8/2/07, Kathy Cochran wrote:
>Okay, I have a question. I am remodeling a house built in 1940. Steel
>frame casement windows. Single pane. Northern California. COLD in the
>winter! I think the BEAUTY of steel frame windows is that MAGNETS can
>stick to them and hold up "hand-made, quilted and batted" insulation
>"shades". What should I stuff them with...............aluminum [foil] in
>the middle or just batting like a nice warm quilt? Please advise. Winter
>isn't TOO far away.
>
>Thanks.....Kathy Cochran
>
>
>> [Original Message]
>> From: Keith Winston <keith at earthsunenergy.com>
>> To: Greenbuilder list <greenbuilding at listserv.repp.org>
>> Date: 8/2/2007 1:02:33 PM
>> Subject: Re: [Greenbuilding] Windows - double hung
>>
>> Hi And welcome John (and hi Laren):
>>
>> That's a good article you linked to, John. Does a nice clear job of
>> spelling out shortcomings of double-hung (I'd never thought about the
>> double-sided exposure of the bottom edge of the upper sash issue, for
>> example).
>>
>> And thanks for the addendum Laren, like so many things its one of those
>> things (window screens) that I knew all the information but hadn't put
>> it together and considered implications in a consistent way. Thanks for
>> helping me do so.
>>
>> Warmly, Keith
>>
>>
>> LarenCorie wrote:
>> > From: "John E. Beeson" <jbeeson at quinnevans.com>
>> >
>> >
>> >> does anyone recommend a manufacturer that makes a good
>> >> double-hung?
>> >>
>> >> And yes, I read this already, but I'm trying to match the historic
>> >> windows:
>> >> http://www.thermotechfiberglass.com/Column3.htm
>> >>
>> >
>> > Hello John;
>> >
>> > There is another factor, that virtually all of the window
>> > manufacturers, and the article above, miss, which makes
>> > all sliding and hung windows even less energy inefficient,
>> > compared to hinged windows. It has to do with Solar
>> > gain, and has been left out of every claim of Solar trans-
>> > mittance, I have seen from a manufacturer. First, sliding
>> > windows are set deeper in their jambs, so they receive
>> > less sunlight at higher angles of incident. This might not
>> > be very important, except for the second, far more
>> > important factor. All of the sliding windows put their
>> > screening on the exterior, where it blocks 15-20% of
>> > the sunlight, from ever getting to the glass. The screens
>> > also reduce the opening size, leaving much of the sun-
>> > -light to just shine on the sill, or jambs, outside of the
>> > actual window. You will not see this mentioned in
>> > any of the manufacturer's literature, and if you mention
>> > it to any of the window sales people (this can be fun,
>> > and even profitable, if you turn it into a question and
>> > a bet ;O), they will hear something they never thought
>> > about before. However, in any heating climates, like
>> > here in Michigan it is a very important factor. In the
>> > Ann Arbor area, south facing windows should gain
>> > more heat than they lose, every month, except may-
>> > -be December. They should reduce the heating bills.
>> > However, when you stop 30% of your Solar gain,
>> > by placing a screen a few inches out in front of the
>> > glass, you are definitely not being green. Hinged
>> > windows place their screens inside, where they do
>> > not shade the glass. This is a critical factor on all
>> > exposures, except north. In southern states, where
>> > cooling is a greater factor than heating, you will
>> > do better with double hungs, because of their
>> > shading screens, and operable top sashes.
>> >
>> > -Laren Corie-
>> > Natural Solar Building Designs, Since 1975
>> > www.LarenCorie.com
>> >
>> > -LittleHouses- http://groups.yahoo.com/group/LittleHouses
>> > -Energy Self-Sufficiency Newsletter- Free at www.rebelwolf.com
>> > -WoodGas- Power from Wood. http://groups.yahoo.com/group/WoodGas
>> > -Refrigerator Alternatives-
>> > http://groups.yahoo.com/group/RefrigeratorAlternatives
>> >
>> >
>> > _______________________________________________
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>> >
>> >
>>
>> --
>> Keith Winston
>> Earth Sun Energy Systems
>> Hyattsville, MD 20781
>> 301-980-6325
>> send me mail at
>> keith at the company below
>> www.EarthSunEnergy.com
>>
>>
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>
>
>
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