One of the easiest ways known to our grandmothers – working battery cover with a damp towel (or damp cloth). The cloth will dry, and the air in the room to hydrate. If the towel dries too quickly, you can put at the battery a basin of water, lowering the ends of the towel.
Another "grandma's" method – bowls of water set on the radiators. Now in hardware stores you can purchase a more "advanced" version of the container for the water with special mounts that securely attach the design on the battery.
Both listed methods are quite effective, but they have one drawback: it is impossible to say that the towels on the radiator or bowl with water make the interior more stylish. If you want to increase the humidity in the room and also to decorate the room – you can install a decorative fountain or an aquarium (without fish, just rocks and a few aquatic plants). In addition, to humidify the air, and using the potted plants, water-loving wet soil will release moisture not only flower, but also the air.
To humidify the air in the room, and using ordinary household spray bottle. Spray water curtains, draperies, and just spraying moisture in the air.