Personally I think I'd like it better without them - I find there's enough going on on the exterior that I'd prefer the simpler window look. I speak from personal opinion, though, not any sort of expert knowledge.

Frank Lloyd Wright's Prairie Style homes had windows adorned with distinctive patterned and adorned windows, though not typically muntins or mullions.

Clear Windows except one. I don't even want to talk about mutins; the only window with mutins in our house (per my design requirements) will be a 10'x2' transom above the entry door. The millworker building it could not find a glass supplier to supply glass with black mutins (4 of them) and wants to use dark bronze saying they will look black, to me they look like bronze and not black. I want black mutins hence he's going to try and get the 10'x2' glass (with mutins) from Marvin; there will be a delay but I'm not worried, the transom/entry is under a covered car port/porch.

Since you knowingly (or perhaps unknowingly) chose a bit of Prairie-style look it would seem fitting to emulate the Wright origins. Of course, even the most basic reference involves more cost. And since most people don't know Wright from Wrong, it's not like the sky will fall or anyone complain should you leave all the windows blank-eyed.

I think the muntins add some needed interest and work well with this house.

With. It definitely adds interest. Without feels like holes in the house.

@cpartist - Wow, I think we agree on something... I don't think my architect had muntins in mind, because I did not see them on any of his exterior elevations.

I feel like the muntins will definitely tip the house towards the prairie style, which I think would cause us to choose a more earthy/older feel for the interior decorating and finishes. Going without the muntins would instead tip the house towards modern, and have a newer, brighter, more sterile feeling interior.

My wife and I are the outdoorsy type, we like camping, hiking, and other outdoor activities. We still are drawn to the clean modern look though...

Those that are in favor of the muntins, do you think every window should have a muntin? Or should I only put muntins in the big windows, and leave them out of the smaller windows upstairs?

@cpartist - Wow, I think we agree on something... I don't think my architect had muntins in mind, because I did not see them on any of his exterior elevations.

LMAO. I think the sea just parted too! And I also like where your office is...

Mike I just removed the muntins from the front elevation only and that was enough to convince me to do them on the smaller windows too.

BTW: I'm glad to see you keeping with the more simplified palette on the house. I like it with just the two materials. (I'm still not convinced about the thingy, but it's growing on me.)

Without the window grids, the house reminds me of those 1970's modern style houses covered in T-111 plywood. (Those types of houses are all over the place where I live) The grids really add something to this house. Just my opinion though. This is going to be a very striking and interesting house when it's done. Nice!

Well...is it Prairie Style or not? If yes, then yes to window grids. If not, well...