All of my guineas are housed in two sheds. The sow shed is 6ft-4ft and has three floors, the sows have free run of this shed, with tunnels and tubes to play in. My little matty also lives with the sows its his harlum of ladies and he loves it, needless to say yes he is neutered thank god. They are all beded on shavings, and have igloos and a wooden box for there beds.
In the other shed we have the boars, and the mating couples. They are all in hutches, they do not have beds but they do have a heater so they arnt cold. Guinea pigs are very hardy animals, but draughts can cause chest problems, therefore if housing outside in hutch it is adviseable to bed them down with hay and cover hutch in clear plastic in winter. After saying they are hardy animals they have been know to die cos they are to cold in winter, so bedding them with hay will help them keep warm also if they are not alone they will help keep each other warm.
For guinea pigs that have problems living on shaving's due to the dust they can be bedded on peat, which is dust free and very absorbent.
Indoor hutches for guineas are ideal as long as not near draughts, ie window or door. And not in the hottest room of the house which is usually the kitchen with bursts of extra heat of cooker and dryer etc. If kept near kitchen they become very aware of the sound of the opening fridge and greet you with loud wheep wheeps when opened good if your on a diet remind you to get out of fridge ha ha.