We just finished making 33! (33!) interior storm windows. This year, we inserted shrink plastic in the custom frames we made with about 5/8" wood. Turns out this was a good idea, since many of our windows are out-of-square and these windows ended up being pushed in to fit. You cannot tell they're plastic, since they all are behind wood slat blinds. We'll look at our gas bills before we decide if we want to replace the plastic with plex. I'll report back about any future energy savings, but I notice already that on a windy day, my wood blinds and window treatments don't blow and billow at the windows the way they used to! Thanks, everyone, for all the helpful suggestions and vendors mentioned here. It helped us immensely. Pamela

Thanks Oberon, I didn't know one could specify a coating on the "outside" of an IG unit. That's a good idea for storm windows. My idea of using the big box to order replacement glass now won't work----they won't sell it unless I am specifically using it for one of their manufacturer's windows. I'm not---I'm making storm windows. So, now the price of glass has doubled and tripled based on quotes from the mom & pop shops I've talked to (none of which seem to know much about coatings and IG). So, I may be forced to use single-pane 1/4" glass. But, before I give up on IG, I want to poke around a bit more. EfficientWindows.org (if I'm reading it correctly) says clear, single panes get 1.04 U-factor and double-pane clear is 0.50 That seems a big difference and that's without any coating. What they don't say is the thickness of the glass panes in either example. Is that likely to be 1/8"? http://www.efficientwindows.org/glazing_.cfm?id=1 Their stated 0.50 U-factor is based on double-pane, clear with a 1/2" airspace. But again, they don't say the thickness of the glass. http://www.efficientwindows.org/glazing_.cfm?id=3 My winter temps average 20's nighttime & 30's daytime. Since my old drafty home never gets warm in winter or hot in summer, what are the best thickness choices for an IG unit? I was thinking 5/8" overall (two 1/8" lites with 3/8" airspace) but maybe another configuration is much better given performance & prices. Maybe 1/2" overall is good enough and much less expensive. What do you recommend? I am gearing up for winter! I'm new to this area (I'm from Los Angeles where I also had an old, drafty home but never really noticed). Thanks very much for all the great advice Oberon. You are a real asset to this forum. -Chris

@overhear Before the last two summers' restoration work, many of the sashes were painted shut, and a lot of the aluminum storms didn't open more than 20 cm (8"), so we have a lot more air movement in the house now. Most of the summer, we're able to keep the house cool by closing everything up during the day, and then opening windows and putting window fans in the bedrooms at night. Considering that the house has no insulation in the walls, this is no small feat! I was initially concerned about whether enough breeze would get in because of the way the casements open, but it wasn't an issue last summer. As for maintenance - the house is covered in original, 140-year-old wood trim, including a lot of "gingerbread" that I've been stripping and restoring over the last two years. The old growth wood is in amazing condition, (other than a few areas with rot that I repaired with Rhino wood repair - an amazing product!) In general, new growth wood doesn't last nearly as long, but when primed and painted, new wood windows will last longer than vinyl replacement windows, which are rarely guaranteed for more than 10 years. Mine are made of accoya, which is a specially treated wood product that is supposed to last up to 50 years! I'm estimating that touch-ups to paint will be necessary every 5 years or so, but the trick is to keep up with touch-ups so that a major repainting isn't necessary. Putty should be replaced every 20 years (mine have gone too long!) but my storms have wood stops so they won't need to be redone. This website has a lot of good information about wood windows: https://www.oldhouseguy.com/windows/

I talked with Molly at Adams! She was very nice and super helpful. We went through ALL the options. ;) i liked the self storing unit as well, but we have large windows and the cost kept climbing (mahogany, priming, painting, shipping). They do have an RTA (ready to assemble), but we weren’t willing to take that on. One of the main hiccups was they didn’t have installers or someone they worked with in our area (this applied to Quanta as well). Our contactor thought we were crazy to keep the old windows (HCOL area and most houses are gut renovated and expanded). Our architect was supportive and through one of his other clients we found someone who installed Mon-Ray . i liked the Mon-Ray units (we saw a sample), but the upcharge for a custom color was crazy. Our contactor was willing to measure and install, but his price reflected the learning curve. We really wanted someone who could measure and install who did this consistently. Old windows aren’t necessarily square, the angle of the sill needs to be correct and there is the center rail that needs to line up with the sash meeting rail, etc. i finally found someone south of us who was willing travel.