you might want to make your decision according to the seasons, if it is winter (many winter months are gloomy ) you may want to use bright colors to keep life in the room and in summer you may want to tone it down perhaps with a sand beige or a mushroom so that the walls don't glare out your...
just a lucky guess: maybe B.U.S stands for no Back Up Switch. Go to a systems installer and ask if your system needs one, or if it needs some type of voltage regulator