Insulating original windows

Hello! We are in the (long) process of restoring a 1930 bungalow that has 20-odd double-hung windows. My husband is repairing them himself, and since the cold weather has arrived, we are again trying to seal up as many gaps as possible to keep the heat bills down.

Something we've been wondering regarding insulating: does anyone have a tip for insulating the top of the lower sash, where the sash cord runs? I can post a picture if my description is unclear. There is a gap all around the sash cord, and it seems like we lose a lot of heat there. We have cut pieces of foam to fit around that space, but this doesn't seem like the best solution.... or is it?

Look forward to hearing your ideas!

Tags: 1930, bungalow, insulate, repair, sashes, weatherstrip, windows, wood

▶ Reply to This

Replies to This Discussion

Permalink Reply by Mark Landry on December 13, 2009 at 2:31pm

Adrienne, it sounds like you mean the groove in the sides of the sash where the rope sits, is that right? A picture might be helpful. We often weatherstrip the jambs of double hung windows with V-shaped bronze made for this purpose. "Insulating" is different than weatherstripping so I'm a little unclear as to what you're looking for. Anything you do to insulate will probably make the sash more difficult to operate.

▶ Reply

Permalink Reply by Adrienne M on December 13, 2009 at 2:54pm

Thanks, Mark. Yes, weatherstripping is what I meant. I was lumping that together with insulating -- which is one of our other ongoing projects. Just mentioned this to my husband, and he thinks he's seen this weatherstripping before.... now to find a place to get it.

▶ Reply

Permalink Reply by Mark Landry on December 13, 2009 at 3:20pm

Here's one place: http://www.kilianhardware.com/vshapsprinbr.html

▶ Reply

Permalink Reply by Adrienne M on December 13, 2009 at 8:43pm

Thanks for the link! These may have to wait until they fit our budget. In the meantime, we were wondering if anyone had designed a simple "cap" for the gap around the sash cord...something to set around the cord and over the gap where the most air is leaking. It seems like a simple idea, so maybe there's a practical reason it hasn't been done. Either that or we just haven't found them. I like the idea of weatherstripping completely across the top of the lower sash, too.

We might just cut thick felt or foam to fit in the gaps for now. Just to illustrate and practice in Sketchup, I made a model to show the gaps around the sash cord (didn't show up well in the photo I tried to get). I'll try to attach it here.

▶ Reply

Permalink Reply by Adrienne M on December 13, 2009 at 9:24pm

Here's a model of the gap (I am new to Sketchup and would love to learn to label with arrows...also, my window nomenclature is not so good):

▶ Reply

Permalink Reply by Lair Tienter on December 14, 2009 at 11:06am

I use rope caulk. It is like a putty and comes on a roll. It is several ropes wide and the roll is maybe 10' long. You just cut off the size of rope caulk you need and press it in place. It doesn't harm the finish and comes in white and wood tone colors. In the spring you just peel it off and throw it away because it will be too hard by the next fall. The price is very reasonable.

▶ Reply

Permalink Reply by Adrienne M on December 14, 2009 at 11:17am

That makes sense.... we use that to seal up around the rest of the windows. We have some Mortite ready to use... just hadn't thought about using it around the sash cord. I'll try it, but I need to get started right away, since this could take a while with all the windows to do.
Thank you!

▶ Reply

Permalink Reply by John Leeke on December 14, 2009 at 6:51pm

We make these all the time and call them "meeting rail tickets". Cut a little "ticket" of thin slightly flexible plastic (out of an empty plastic milk jug), make it as wide as your sash is thick, and about two or two and a half inches long. At one end cut a slit and hole (same diameter as the sash cord) that fits around the sash cord, fit the slit-hole around the cord, lay the "ticket" flat, slide it over so the edge is just shy of the sash track, and staple the "ticket" to the top edge of the meeting rail--slick and quick.

If you don't get it from that description, send me your sketchup file and I'll show you. (johnleeke at HistoricHomeWorks dot com)

Also, for windows you don't need to open and close a lot in the winter, consider making interior air panels, the meeting rail tickets would not be needed. The air panel blocks a lot more air infiltration and provides an insulating air space. Here's how:

http://historichomeworks.com/forum/viewtopic.php?t=193

John
Save America's Windows

▶ Reply

Permalink Reply by Martin on December 21, 2009 at 4:42am

wow that is a good idea!!! This is something I should do, especially where I am missing some exterior storm window glass.

▶ Reply

Permalink Reply by Steven Thomas on March 31, 2011 at 9:33pm

Only thing you need to be worried about is condensation. Since the air on the inside is warmer.

▶ Reply

Permalink Reply by basswood on January 12, 2010 at 7:24pm

I made storms like this for my shop, but I put plastic on both sides of the storm frame to make a "thermal pane storm." So far, very little condensation between the plastic layers. I should try some with this method inside the house and keep an eye on condensation (I suspect that the air between the layers of plastic is mostly warm enough to stay above the dew point). The next set I make I will plow grooves for screen spline so it will be very easy to replace the film. No tape, and by pressing the spline into the groove, it will help pull the plastic film tight (less bagging or wrinkles).

The film and spline can be on the outside of the frame only, if you don't like looking at it.

Regards,

Basswood