Our house is about 20 years old with rosewood (dark brown) upvc windows. They look ok on the house but I wouldn't have chosen them myself.

We are having a large kitchen diner extension at the back of the house and I'm not sure what colour windows to have. It will have bifold doors, a roof lantern, another single door at the side and large window. We can't afford to replace all the windows in the rest of the house. Will it look ok to have aluminium windows (or even upvc windows) in a colour other than brown just in the extension? If we do that, should we be thinking about painting the exterior of the extension so the whole thing looks obviously different (otherwise the dark brickwork will be the same and only the windows different). Secondly, I can't get think of the best colour to go reasonably well against brown. I don't think the standard dark grey aluminium colour or white would work against brown windows everywhere else. Will a greyish green look ok or would it date quickly? Would really appreciate any thoughts people have.