Well, the answer to the TDL v SDL question is easy. In true divided lights -TDL-each pane is installed in its own frame that goes clear through the window. In SDL there is some sort of grille appplied to one surface of the glass, or worse both surfaces, but there is only one pane of glass, so when you look sideways at any angle but dead on you can see the fakery. If I couldn't have TDL, I'd change to a different muntin pattern. You architect is correct, there would be a significant aesthetic loss. Especially since you don't have have that many muntins, in the first place. I'd economize elswehere to make sure I could have TDL. However, before I'd exchange the original older windows for modern ones, I'd look into getting them brought up to good consition, adding wooden storms, etc. This is often cheaper than quality replacements. (Though maybe not so much $$$ for the architect....) You could be saving original stuff and getting excellent energy improvement at the same. Problem is finding someone to do this work in your area. I have just located someone near me to work on my own windows, and delivered four there yesterday for an initial project to see how this worker does. If you keep asking around I think you'll turn up somebody. I found the guy I hired yesterday by keeping my eyes peeled for years and asking around all the time. When I saw a window in at the hardware store awaiting measurement for a reglazing, I recognized it as something that was being rehabbed. I looked it over carefully, and noted the contact phone number on the sash, and scurried home and called it. Turns out my guy does it all the time, but is so busy he never advertises. My advice: keep asking till you find the local version of my window genius. Molly~

How did a discussion about windows turn into a cultural disagreement and charged political discussion? Left, right or wrong, please save the personal attacks. That said...I have an old (circa 1840s Greek Revival home with 6 over 6 double hung windows. Unfortunately, I had to replace them because they were in just too bad of a shape to restore economically. The closest I found in an affordable stock size and style was Brasco Boston 6 over 6 ADL (authentic divided light) windows (sash replacement kit--sash and balances only, no frame). A local mill was able to make custom wooden storms to match an original storm I found in the barn when I purchased the house. The windows cost a little over $100 each, the storms about $85.00. With a little ingenuity, I was able to make the Brascos fit into the original openings (the size difference was only about a 1/2 inch or so). From the outside, the house looks the same as it did in the photos I found at the local hisrorical society. The only drawback is the balances, which are vinyl with a spring mechanism. I was able to hide those with some creative interior trim work that doesn't look out of place. The net result is my heating bill has dropped significantly and my home is a lot less drafty. In the back turn of the 20th century addition that I had to completely rebuild due to structural issues, I bought pricey (stock) Marvin low E with argon 6 over 6 SDL's (simulated divided light windows--(prices ranging from $500 for a single unit to $1,100 for a mulled unit). The muntons are about an 1/8th of an inch thicker than the Brascos which matched the originals, but not noticeable since they are consistent on that portion of the house. Net net...The Marvins look great, operate smoothly (thanks to the quality balances) and are tight and completely draft free, but expensive. The Brascos look very close to the originals and with the storms seem to be as efficient. If I were in the position of the original poster, I would probably get removable interior storms and only put them in during the coldest months. The good ones don't look too bad and are a lot less expensive than replacing the windows. And my guess is the energy savings would pay back the cost within a few years or so. Perhaps Oberon can do the cost recovery calculation for you.

OK , its official, I am anxious over my Plumbago. I planted it right before the first VERY EARLY unlooked for freeze. I think it was making tiny green earlier this spring, but then we got the VERY LATE unlooked for freeze and bye bye green shoot.. I just dug it up and scratched a brittle twig below soil line and YAY it is green! My Mexican honeysuckle is in the same dead looking boat but it has made an ever so tiny appearance. I was apprehensive of a ammonia ciliata that was advertised as liking the caliche flat limestone marl in habitat here in Travis county. Well I had some habitat for it and it is dead sun and unfriendly as all get out. It has sent up three stalks and is putting on some blooms. I was hovering like a worried crow over a barren patch of gravel mulch where there might be a subtererenian silver leafed ironweed from the Big Bend. We did have a wet winter and I was worried that it might have been too wet for this new species that says "For Western Gardens only". I am on the wet side of that no mater how much I moan and groan about how dry it is here. I think I see something but I also have seeds volunteering in the area. I am chanting to myself. " I will not dig it up, that is like picking at a scab"

@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/