[anon291]

My home has muntins, and I have to say they are incredibly convenient. If a ball goes through a window or something, it's extremely easy to replace; and very cheap. Highly recommend.

As for glazing... I'm not 100% sure. I've heard there are ways to get glass panes that are better insulated. My other guess is that, had muntins continued to be popular, the market would have found something. There's nothing inherently inefficient about them.

For example, one option a local window company gave to me was to simple add some plastic covering on the inside of the window. It would not reduce the outward appearance at all, but would provide some insulation. As it is, our house is quite efficient and we don't actually have any insulation. The way they used to build houses (not open floor plan, multiple stories, etc) actually make them more pleasant to live in, in my opinion. Our only issue was that, when adding AC, the original forced air venting leads to a noticeable temperature differential due to the lack of an intake on the second floor, but we'll be fixing this soon. Plus, ceiling fans have basically eliminated the worst of the problem.

[nemo44x]

Nowadays the window that was broken would just be replaced. Luckily they pop out easily!

For your old windows (I have many still, mainly in the front) I recommend ensuring you have good weather stripping and that you have storm windows installed. That helps a lot. Mine are double hung sashes though so the pulley boxes are massive leaks but nothing I can do about that.

I guess I could just seal the windows shut and put insulation in the pulley boxes but they are still functional even though we rarely open them.