ok, so natural gas would win out in the above synopsis. in a normal gas furnaces, would running a fan all of the time help in moving air throughout the home and keeping a more even heat? I am experimenting running my fan while the heat is off the last couple of weeks and I am finding that the heat tends to kick on more as I assume air movement is better to the thermostat. Regarding the solar, on the longer / brighter summer days i produce just over 50 kWh, over the past couple of weeks (november) with less sun, it varies from 5 kWh on very overcast / cloudy days up to 32 kWh. winter sun is lower and shorter hours vs summer. Until i have a full year under my belt, it will be hard to fully understand the true savings and production. Thanks for the cost comparison. It may be better to stick with gas as the solar produces a lot less in the winter sun. the strength of our area is that is covers a lot of energy when our electric use is the highest with AC on.

Glass was also taxed on size in some areas (mostly in Europe) so the way to cheat the tax man was to use smaller pieces of glass which were less costly tax wise. (This was particularly true of mirrors which were heavily taxed). So it was both initial cost and cost later :) Just like us today LOL Windows were also made from the bottom of glass bottles in many places in the country. You see it on occasion in England and in original window's in cabins in the US (my grandfathers place had a couple). They were a poor man's glass window. I'd take a couple things into consideration in choosing. Style of house, and what you're blocking with the extra wood. In my home, I'd never want the smaller glass expanses because I am on a lake with fabulous views. I don't want tiny squares of lake...I want huge expanses of lake (some of my windows are 6'x8' picture). I'd never want to change that to fill a style desire :) But in some homes...the view is not a main feature, so I'd think about what looked best on the house, before I'd consider the view out of the windows.

Thanks for your thoughts. I only began to consider the Marvin because I was having so much trouble finding a quality vinyl window near me that can be ordered with SDLs. Improving the curb appearance with nice-looking windows is sort of secondary to the basic goal of getting a durable, low-maintenance weather-tight window. In this sense, the Harveys might be our cheapest option with available SDLs, and "good-enough" performance, but I've just located somebody who sells Okna vinyl near me, so I'll get a quote there. We'll see if I can afford Okna 800s, since I think those are the only ones available with the grids I want. Maybe I can do 800s in front and 500s (without grids) in the back of the house.

I'm still mulling over the best window options over here and figured I would simplify my questions to the following four I am still mulling over--keeping in mind I plan to be in my home for decades, so hoping to get a window that lasts! Material--would you recommend vinyl, fiberglass or fibrex for a midwest/broad temperature range climate? Warranty--would a lifetime warranty sway you into an inferior product? Sliders--when it comes to replacing two single-hung windows with sliders--do you think one brand outperforms others in this type of window? Anything to be aware of when choosing sliders over casement...other than the very slight difference in efficiency? Brands--I think I'm down to Window World, Marvin (Essential) or Andersen (100). Which would you choose and why?