Depends on your guinea pigs and how deep a sleeper you are. For the most part, they'll settle down when the lights go out, but there will be the occasional water bottle noises when one gets thirsty and sometimes you'll hear them walking around or softly squeaking at each other. Mine are in my room and I don't mind it at all, in fact I like the reassurance that they're there and healthy and that I'm not alone, but I know they could keep some people up.
In the daytime, though, they'll make a racket if they think you're going to feed them and run around. Wheek! Wheek! Wheek!