A whole house humidifier is one that can humidify the entire house. So it needs really large scale capacity [at least 2 Gallon / 7L].

Keecoon especially provides this kind of humidifier. It is water tank Ultrasonic Cool Mist Humidifier which can Moisturize the dry air in your home or offices in minutes. It is ideal for use in medium and large-sized rooms, which up to 500 sq.ft. To create a better home life for those suffering from colds, allergies, and dry skin.

A humidifier makes the air fresher, While a dehumidifier removes a fresh smell. A house would use a a humidifier and a museum would use a dehumidifier

It depends on where you have it in your house and your climate. You need a humidifier for a drier climate obviously. This is the same for a wet climate.

A Bionaire humidifier can have quite a number of various purposes. Their primary purpose and most common use is to increase the humidity in a single room of a house, or in the entire house.

The Bemis 4D7-800 Warm Mist Evaporative Console/Whole House Humidifier will humidify an entire 2,700 sq ft home.