We are in SF Bay Area. Please check out the informative link:

http://www.efficientwindows.org/ftypes.cfm

Most new businesses and office buildings use modern Aluminum windows. Modern high quality Aluminum work very well and are reasonably energy efficient. Even Milgard offers an Aluminum line with low-E.

Those contractors who steered you to vinyl likely have established relationships with vinyl window shops. Vinyl is still the most popular amongst home owners so many more shops sell them.

You may have to locate a shop that sells high quality Aluminum windows to get a contractor who will speak your language.

Good luck.

Okey...vinyl is plastic and plastic like all else is not perfect. I think we all know that, none of the materials are, however there are clear advantages to plastic listed all over the web. Does anyone know of more advantages of aluminium besides that it can be bend to unusual shapes of windows? not interested in that, really.
I am in the middle of making a decision plastic vs aluminium and am leaning towards plastic, does anyone have any other pro aluminium information that should possibly be taken into consideration?

I like your handle, Eichler. We have a 1952 ranch that is slowly becoming "modern". We chose the Milgard dark anodized aluminum. Frankly, it was an aesthetic issue: the slim profile and "invisibleness" of the aluminum just looks better. Vinyl fits some styles of houses just fine, but I have yet to see it used nicely in any modern home, mid-century or other. Since your house has lots of glass, your energy issues are greater than mine, but I vote for aluminum.

There are places for both vinyl and aluminum. Both have pros and cons. People should do there homework and see what works for them the best. Dont just pick something because a saleman told you too.

Updating this thread for others considering aluminum frames:

We did install the Milgard aluminum windows. They are really neat looking! My one regret is that there are a few windows where the old had a fixed pane and a casement. I ordered double casements instead, and probably should have stayed with the original layout. This because the double casements have a lot more 'frame' showing than we originally had.

A few other things:

1.) We had some problems making casements work in some bedroom locations - due to emergency egress requirements. Basically a Milgard casement must be 30" wide for egress. Narrower and it won't meet code - even though the hinges are on the jamb. Wider and it becomes too heavy to work right. So we had to use sliders instead.

2.) Energy-wise, Milgard offers 'thermally broken' aluminum frames, but, strangely, not in California. I did order our windows with Milgards "Suncoat Max" upgrade though. It is interesting to place ones hand on the frame and then place it on the glass. Big difference in temperature. However, combined with other things in the construction (e.g., IB Systems membrane roof, and Techshield radiant barrier decking), the house is staying suprisingly cool during the current heat wave. (Got up to 100° yesterday.) And the insulation and drywall have yet to be installed!

So in our case the aluminum frames don't seem to be a big problem. But if one were to insist on thermally broken aluminum, then Fleetwood seems to be a better way to go. (FWIW, I gave the local Milgard area rep a hard time about not being able to order thermally broken in California. Seems silly that you can order them in other states, but not here.)

3.) Milgard delivery was *fast*. Like less than two weeks from order to delivery.

4.) A nit: Our frames are dark bronze color, almost black. For some reason the screws mounting the casement lock handles are bright colored. Yet other screws, such as the ones holding the screens, are black. I need to call Milgard to see if they can provide some black screws to make the bright ones 'disappear'.

5.) For the master bath, I ordered reeded obscure glass, on the thought that it kinda carried the theme of the reeded obscure glass in the sidelight of my front door. (Of course a workman accidently broke the original 1950s sidelight a couple weeks ago, so now I get to match the sidelight with the master bath instead...)

I live in the northwest and have been around Milgard products for years. Thier once great reputation for both quality and service/warranty issues is gone. They are now owned by a national corporation and everything has changed. We recently fitted a high-end home with thier aluminum thermal break line of windows and a slider, over 20K. They have given us the run around for nearly a year over shoddy worksmanship and factory miss-build issues, with no intention of correcting anything. I cannot see them being refered to as high-end no longer.

Here's my two cents worth. I have 30 year old aluminum and I will be finding replacement sealed units. Sure vinyl is better thermally - but I suspect it will take a lot of years to save enough to pay for the difference. I'll bet nobody has researched this adequstely for the simple reason there is way less money to be made by recommending the low cost alternative of just replacing the selaed units.

If any one has seen research please let me know.

As a follow up to the follow up and resurrection of the necro-thread:

I have no regrets on ordering low-E glass in our aluminum windows. They have been performing very well for us over the past three years. Remember that with aluminum, there is a much higher ratio of glass to exposed frame than with other materials. Still wish we could have gotten the thermally broken frames in California though.

And if I owned a Model A, I probably would put radial tires on it... :)

I am updating a 1987 home in Oklahoma. I have been researching vinyl windows versus thermal aluminum. Our summers can reach triple digits while the winters can drop below zero. Which window would be the best replacement for our current aluminum windows?

Thank you for your question and updates. I think you just gave me the answer I was looking for and leaning towards. Aluminum it is! I too have a 70's home that has a mid century look and want to keep it looking the part