The 400, 600, and 700 models have a clever computer system that gives them fully automatic humidifier control. It sets the level of humidity based on both indoor and outside temperatures. These are the larger, low maintenance whole house humidifiers. They are not available in the shops, only through licensed contractors. A contractor will be able to help you choose the correct humidifier for your needs, and do the required installation.
Aprilaire also sell smaller, single room models that use a cool mist wick design.
