The ideal humidity level is between 30% and 50% with 40% being the optimal level for comfort. Humidity that is too high can result in excessive moisture in your home that can lead to condensation on your windows and windowsills and possible mold issues. Humidity that is too low can cause itchy skin, respiratory problems, and cracking of porous materials such as hardwood floors. Humidifiers and dehumidifiers can help with these issues and are available in both portable units for specific areas of your home as well as whole house units, which are mounted to your HVAC system.