dry indoor home air
Humidifiers are simple and cheap appliances that can solve some basic and sporadic low humidity situations. But structural causes of low humidity should be solved otherwise.
A humidifier is an appliance that increases humidity in our houses. The most simple and common humidifiers are used to humidify a single room, but there are also whole-house or furnace humidifiers connected to ventilation systems.
Dry-Air Health Effects
An indoor humidity (RH) of less than 30% causes dry-air problems: discomfort due to excess of static electricity, skin irritation, respiratory problems, and in the long run, cracks in the walls, problems involving furniture, timber walls, floors...
Humidifiers: Recommendations for Use and Care
Humidifiers should be used with some care. Though they can solve some health problems associated with dry-air, they may also be responsible for negative health side effects like proliferation of microorganisms and minerals due to ultrasonic and impeller humidifiers...
It's important to use a humidifier properly, only when conditions require it, and with the right moisture setting for existing conditions.
Dry-Air Measurement
To track dry-air, use a hygrometer (or humidity meter, or moisture meter). These devices are inexpensive ($10-$50) and may be acquired at many hardware stores. Some models of humidifiers include hygrometers.
Causes of Dry-Home Air
There are several possible reasons for low indoor humidity, namely weather and climate conditions. But you should be particularly aware to sources like improper ventilation, and low levels of insulation.
See:
Moisture Control and Mechanical Ventilation
Leaks and sealing
Exhaust fans and Ventilation
Evaporative humidifiers

Humidifiers are very simple appliances. Evaporative (or wick humidifier) is the most common type. It comprises three basic parts: a reservoir, a wick and a fan.
Other types of humidifiers
Besides the evaporative humidifiers we may consider...
- The Vaporizer Humidifier, based on boiled water, releasing steam and moisture into the air. Although inexpensive, vaporizer humidifiers have higher operational costs due to the electricity needed to heat the water.
- The Impeller Humidifier, based on a rotating disc that breaks the water into fine droplets which then float into the air.
- The Ultrasonic Humidifier, based on a metal diaphragm that creates water droplets. Ultrasonic humidifiers demand a regular cleaning to avoid bacterial contamination.
Humidifier prices
Prices between $50-$100 are very common for the most typical models.
See also:
Air quality
Leaks and sealing
Natural Ventilation
Humidity Basics
Controlling humidity
Moisture Control and Mechanical Ventilation
Evaporative Cooling
Mechanical HERV Ventilation
Dehumidifiers
Exhaust fans and Ventilation
