Damn it’s hard to test someone elses work! I’m rendering on GPU, so it’s a lot quicker for me, although it does seem a bit slow to remove the noise, although it builds quick enough per pass.
I’ve not tested before, but you have a sun light and also a sky texture, which I’m sure will probably add to the render time - I could be wrong.
I imagine you’ve imported your model in from another program, max, maya etc. The whole model is full of triangles, it’s not good practice to have models made this way in blender, although whether that ulitimately effects render time in Cycles I have no idea.
You changed some of the defaults in the Render settings I think, what were the defaults like time wise?
Even though they are not visible, the other models, bath, sink, toilet, kitchen, are still getting rendered, I’d certailny move them to another layer if they are not required for the render.
Oh yeah, I also removed the floor as there was no texture (obviously) and the floor was render black.
Darn, wish I could be more help, I always find it hard to spot the obvious sometimes in others work.
Maybe some brain here will point it out to you, sorry I couldn’t help further