Guinea pigs need a weatherproof, predator proof hutch raised off the ground and positioned out of direct sunlight and wind. Allow plenty of room i.e. at least 120cm long x 60cm wide x 60cm high for two guinea pigs.
In cold weather, the hutch should be moved into a shed or porch but do not place the hutch in a garage where exhaust fumes could be toxic to the guinea pigs. There should be two connecting compartments: one for the day and one for night retreat with a solid wall. Guinea pigs like their own separate sleeping compartments.
Ideally, the hutch should be within a secure wire enclosure where the guinea pigs can graze and exercise. Tubes, boxes, logs and flowerpots placed in the run provide interesting hiding places for guinea pigs.