You do NOT want aluminum windows in St. Louis.; Arizona or southern Texas maybe.
Look at a higher end vinyl such as soft lite, sunrise, gorell. Okna or Himark would be a great choice but they aren't available in St. Louis.

There are some very narrow vinyl windows out there that will give you a similar amount of glass and if you don't care for that construction look, I would opt for fiberglass next.

Aluminum is probably not the best bet for your location.

Thanks for the input! In St. Louis who has quality fiberglass? I've been reading in different places that supposedly the Marvin Integrity all Ultrex is a great fiberglass window, YET then people state that it's not so good because of air filtration.

As far as quality vinyl with narrow frames: Any recommendations in St. Louis. Our aluminum windows have a
2 1/4" visible frame (I don't know if that is how wide the actual frame is, or if there is a portion of the frame hiding in the wall where I can't see it :)

Depending on the install, there could be a portion that you do not see and with a full tear out, the net glass might be about the same.

There are several narrow profile vinyl windows that have a net edge of glass to edge of frame measurement of just under 3". If you have 5/8ths drywall return on either side, you are looking at the same net glass opening in this case.

Sunrise, HiMark, and Soft-Lite all make a nice and narrow option.

In terms of fiberglass, InLine is nice as is Marvin Infinity.

The thing with fiberglass is that it can be difficult to get it to hold paint, so it's best to leave it white. For insulation and noise reduction, look into a window that uses a "SuperSpacer." Most window spacers are made of metal but SuperSpacer is foam so it doesn't conduct cold and heat as much as metal.

Any window is going to get condensation when it's cold outside, warm inside and the humidity is at a certain level -- especially if you keep it covered with curtains or shades. So whatever you get, don't leave curtains or shades fully closed all the time.

Fiberglass window, much like vinyl, are available in a several stock colors in most cases and some manufacturers have the ability to paint the windows any number of customer color.

At no point in the process would I ever recommend a customer buy a new window to paint it.

+1 on factory colored windows (vinyl or fiberglass) = no worries.
+1 on a non-metallic spacer like super spacer or duralite/heat seal. The stainless options available now offer decent performance as well, but I'm partial to non-metal when possible.

Thanks all for your comments. It did create a few more questions.

1. Which Softlite brand is more narrow? Softlite was out to the house this week and the Elements he showed me had a 3 3/4" frame.

2. I'm assuming the more narrow frame will not get out of shape after being in the heat for awhile? And, it will still open and close and lock easily?

3. Concerning STC: I automatically assumed anything I got would have better sound insulation than my builders grade aluminum windows. But, then I read how someone got some vinyl windows and she hears the road noise so much better.

a. Will the fiberglass be more or less sound insulating than aluminum?
b. How about vinyl?

4. The air infiltration for the Infinity is .09. What does that mean in real life experiences? Will I feel a draft?

Thanks so much! Stephanie

1. The Bainbridge is the narrowest of their windows and the Soft-Lite Pro is also narrow.

2. Not necessarily. Soft-Lite is a well engineered window so it, with the optional meeting rail reinforcement, should be fine but some other narrow windows will not fare as well.

3. Typically, replacement windows, as a result of their thicker glass and more airtight insulation, will perform better. There are applications where the existing combination (usually with a storm window) might out perform the new double pane IGU window but not if you have single pane window without a storm.

a. and b. Impossible to say without knowing exactly what type of window you have now. If you have single pane, both will outperform your existing windows. If you have double pane, it is very likely that your new windows will still outperform and be more sound resistant than your existing windows.

4. 0.09 is not drafty by any means and will probably be a huge improvement over your existing.

One thing to keep in mind is that the overall "tightness" of the new window and the ability of air to move through and around it will have an effect on sound in as well. Most cases where I've seen folks complain about hearing more noise after replacing their windows are when they chose a more "cost-effective" product.
In the Softlite lines, The Elements/Imperial LS is their top level offering, however as you have identified, it has a slightly thicker frame/sash than some of the slimmer units like the HiMark, Okna, and Sunrise Restorations. As WoW mentioned, the Bainbridge and Imperial Pro do offer the slimmer lines, but not without a decrease in quality/performance. That being said, I would not say that any of SL's products are less than above average, so you are still in good shape that way.

Which Infinity product gets a .09 air leakage rating? The casement? The last time I looked at it, it was over a .2 in as a double hung, which is not very good.
I would request a test spec sheet on that from your salesperson.

The infinity double hung has a rather high air leakage rate. Karate guy is correct.

Thanks all. I'll give Marvin a call and get specific numbers. I had gotten the .09 off of a piece of literature.