Why aluminum on the exterior?

Are you needing a specific color?

Thanks for your question. We are trying to blend with a set of Nana doors which are all aluminum. The Nana windows are not NFRC rated so we can't use them. Looking for a close match.

What color are the doors? If they are anything but mil finish, there are other material options that should give you a bit better performance.

The most efficient aluminum windows have a thermal break to give you the rating that you will need.
Also consider fiberglass. You can get the color and the thinner profile replicates the "aluminum" look.

+1 on wow suggestion, Aluminum, Aluminum clad wood, Fiberglass and or Vinyl or often mixed on projects as he stated. The exception being just as he mentions Clear Anodized which most companies cannot match.

Thanks to everyone for their thoughts. The Nanas we're putting in are going to be a Medium Bronze. That gives us some flexibility because I believe that most companies that produce aluminum windows will do a similar color. Good point on the thermally broken feature. I forgot to add that was also on our short list. We had not considered fiberglass and will look that up now. Does anyone know of a brand that we should check for either material? There are so many manufacturers that it's hard to know where to start.

Marvin Integrity is probably the most widely available window of some merit that has a bunch of different options and a great company behind it.