insulated window curtains

[Scott Loupin]

Anyone know of any sources for insulated window curtains, or directions on
how to make them? Some of our windows, although low-e, argon filled, etc,
are cold.

Thanks in advance.

Scott

 

[Derek Broughton]

Anyone know of any sources for insulated window curtains, or directions on
how to make them? Some of our windows, although low-e, argon filled, etc,
are cold.

I know they used to be advertised regularly in "Harrowsmith Country Life"
magazine, but I haven't picked up a copy in years.

You want to be really careful about doing this. For North or West facing
windows it's probably safe. For South-facing, it might be. Don't do it on
East windows. If they're tight enough to really work, you can end up
gathering enough heat between the window and the insulation to blow the
seals on the panes before you open the curtain. A local passive-solar
builder has experimented with this at considerable cost :-(

 

[Derek Broughton]

Very interesting. Could you describe the environment and circumstances
in which this happened (including maybe what windows are at risk)?
Seems to me that the S-facing windows would be at most risk here, and E
at next to lowest. Oh- that's in CT, US of A.

East windows are at risk if they can heat up before you get up and open the
curtains. S. window curtains are more likely to be opened before they get
to be a problem. Really, W. windows - exposed to the setting sun at the
best angle of incidence - are the ones that heat up the most, but you're
not likely to have the curtains closed at the time!

I don't have a complete recollection of Don's experiments, but I think it
often came down to windows where the homeowner left the blinds closed all
day - for instance a bedroom which the occupants left in the morning
without opening them. In the main living areas, you're not likely to leave
the curtains closed when it's light outside and you're up and about.

 

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... I think it often came down to windows where the homeowner left the blinds
closed all day...

We might collect solar heat and avoid damage by leaving an opening at the top.

Nick

 

[Derek Broughton]

We might collect solar heat and avoid damage by leaving an opening at the
top.

Probably. You just need to be careful and consider the possibility of
whether you can overheat that space. I don't even know what temperature
you'd need to worry about.

 

[JoeSP]

Anyone know of any sources for insulated window curtains, or directions on
how to make them? Some of our windows, although low-e, argon filled, etc,
are cold.

Thanks in advance.

I'm assuming the plan is to stop heat loss radiating out through the window
pane, and to avoid the convective heat loss caused by cool air behind the
curtain spilling to the floor and pouring out into the room. In lieu of a
commercially-available solution, here are some suggestions.

Two factors are necessary to accomplish these two goals:
Firstly, an insulating and reflecting material in the curtain to lessen
radiant heat loss. A sheet of reflectix or ayrfoil-type material is probably
the most cost effective for this purpose. A light-colored quilt may serve
that purpose too.

Secondly, the airflow behind the curtain should be reduced by either
fastening the curtain to the wall with something like Velcro, or installing
a thick, soft cushioning material from top to bottom and along the sides.

In addition, I would apply a clear plastic barrier over the window for the
winter as a first line of defense against the cold.

 

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... how about a duofold blind that has an integrated solar collector?

Sounds cool. What's "duofold"?

It could have a slot opening across the top and one or two plastic film
dampers at the bottom to prevent reverse flow? It would automatically
transition from insulating mode to collecting mode? The slot across
the top would have little effect on its performance as a window insulator?

Sure, but it would be nice to avoid the plastic film, which is somewhat
fragile and may leak and may not work very well with a small height diff.
How about a "flow organizer" instead, with the only openings at the top?
At night, air stays trapped inside. During the day, cool air flows in
at the top and falls down next to the glazing and gets warmed as it flows
from south to north through a dark mesh and flows up and back out just
above the cool air entrance. This would tend to make the shade deep in
the NS direction, ie it might project into the room a few inches from
the inner glazing.

The incremental cost over a regular shade would be so small that you could
afford to add it to east or west facing windows, even though they are not
ideally oriented for collecting? This is literally a 10 cent solar collector
if you only consider the incrmental cost over the shade.

Sounds nice

Nick

 

[[email protected]]

I'm just going to try the plastic film dampers for a start, since I know how
to make these work -- maybe flow organizers later -- is this the same as the
Delaney concept?

Yes, but simpler, with only 1 "chimney" in the center. After lots of 3D head
scratching, I found a way to make it from 3 simple layers of foamboard, IIRC,
an inboard layer with a gap at the top, and 2 vertical foamboard strips inside
that to support the mesh... I can't recall the organizer geometry, but the
result was too thick for the windows I had in mind, so I tossed the sketches.

Nick

 

[A Veteran for Peace]

Anyone know of any sources for insulated window curtains, or directions on
how to make them? Some of our windows, although low-e, argon filled, etc,
are cold.

Thanks in advance.

Scott

I've read a great book on this. "Movable Insulation" by William Langdon
ISBN 0-87757-310-0
old might be OoP.

 

[Nick Hull]

Anyone know of any sources for insulated window curtains, or directions on
how to make them? Some of our windows, although low-e, argon filled, etc,
are cold.

I just use custom cut pieces of 1" thick styrofoam right against the
glass. Has been working well for 25 years.