Another safety factor is that some hamster cages end up being put in drafty areas of a room. (choosehamstercages.com)
They should have bedding or beds that are kept away from drafty areas. (spcanevada.org)
Large drafty areas that are protected from moisture and sunlight can be covered with expanding foam sealant, while a little weather - stripping around door jambs goes a long way toward keeping the cold out. (scientificamerican.com)