I'm a novice remodeler, so forgive me if this is a dumb question --

I'm replacing our old door with a simple 5-panel painted front door with frosted glass panels and 2 sidelites. I told my contractor I wanted the framing around the front door and sidelites to be an anodized aluminum or steel finish, to go with the new glass/anodized aluminum garage doors we are getting. He looked at me like I was crazy and said that metal framing would transmit cold into the house in the winter (I'm in Denver), and I'd even end up with frozen ice on the inside of the house. Is that true? If it is, can I do wood framing on the inside, aluminum on the outside? Our door is a standard size, so is it possible get non-custom framing that will work? If not, how much will it cost to do what I want?

Thanks for any advice.

You should be able to get a commercial storefront company to build and install the frames for your entry door. Make sure they use extruded aluminum with a thermal break, meaning that the aluminum is not solid; it usually has some type of polymer between the inside and outside to slow the temperature transmission.