Increase cycles speed for interior render I modeled a house and wanted to render the rooms from the inside with the approximate sun lighting through the window. However cycles is incredibly slow in doing that. What should I change to increase my render speed? I am okay with sacrificing quality for it as it is not yet my final render and I am still planning the room layout.

The room is physically correct with ceiling and floor (cube with multiple small holes in it). I'm rendering in perspective mode using Cycles.
It sounds like you are using a sun lamp for it, that really slows it down. So the only thing I can add to Gwenn answer is: for interior renders, use planes with an emission shader in every window hole, and disable the "camera" option in the "ray visibility" panel in the object properties so you don't see it when rendering. You can combine that with a sun lamp if you want hard edge shadows coming from the sun.

I use this method a lot and it really speeds things up.