You should keep hamsters away from direct sunlight, drafty areas, and heat sources. The heat sources can be any fireplace or a stove. Moreover, the location of the cage must be peaceful, as loud noises may stress the hamsters. Another thing you should consider is that the area should be such that frequent light switching won't happen. Above all, hamsters love to run on their exercise wheel, so choose an area where you wouldn't be bothered by its noise at night.