Use cotton or synthetic blankets instead of wool. Air your mattress at least once a month. Keep rooms well aired and open windows daily. Consider replacing carpets with linoleum, tiled or polished wood flooring which are easier to clean and don't harbour house-dust mites. Humidity occurs when water is contained in the air in the form of an invisible vapour.
Humidity levels vary with the temperature of the air.
Steam from the bathroom or kitchen can add to the relative humidity of a room. Dampness can occur when warm air indoors comes into contact with a cold surface, such as a window. Condensation forms because, as the air cools, it cannot hold as much water. Open windows or use an extractor fan to increase ventilation, especially during and after cooking or when using the bathroom. Cover pans when cooking.