A hygrometer can accurately display the actual humidity level within your home. 45-55% is about right for the average UK home. A digital hygrometer will enable you to know for sure if your home is too dry or too damp and act accordingly. If it is too damp, then you should use a dehumidifier to control the excess moisture. If it is too dry, then you should opt for a Humidifier to add moisture to the room for you.