Try not to put a cage by a radiator, or a window or TV, like pictured. (The cage isn't usually here, it was an example).
If near a window, drafts ca mnake a Guinea pig ill if it is open, from the cold, just like in humans.
If near a radiator, they can get too hot if the radiator is on a lot, and if they get too warm, they can’t really cool down, and walk out the room like us humans.
If near a TV, then it can hurt their ears, TV's give of sounds that us humans cannot hear as the frequency is so high. Guinea pigs can hear about 54,000Hz (Hertz). This is very high as Humans can only hear about 18,000Hz.
Try and get the cage in a family room, ideally opposite from an all these places, perhaps far across the room, on the other side. The guinea pigs will still hear the TV most likely, but it won’t hurt their ears much as it would have. The drafts won’t make them cold and the radiator wont over heat them, if they're further away.