Fill a cooking pot with water and bring the water to a boil. The steam from the boiling water will add moisture to the air. Replenish the water as needed to continue adding humidity to the kitchen and surrounding rooms.
Leave the bathroom door ajar when taking a shower. This allows steam from the shower to carry humidity to the bedrooms and hallway near the bathroom.
Place a grouping of houseplants in a room that needs increased moisture in the air. Water the plants as needed. The plants will add humidity to the air through a process called transpiration.
Set a decorative bowl in each room and fill it two-thirds full with water. As the water evaporates, the moisture level in the room increases. Replenish the water in the bowls as needed.