Don Vandervort, Head Homeboy, has written more than 30 DIY home improvement books, been a segment host on HGTV, served as MSN.com's home improvement expert and written countless magazine articles.
Some humidifiers disperse water vapor into the air the same way a tea kettle does: by boiling water. Steam units are manufactured as tabletop or wall-attached models that spray steam into a living space or into forced-air heating ductwork through a dispersion tube.
With all models except for tabletop varieties, tap water is piped directly into a steam unit so that it doesn’t require manual filling. Because steam is evaporated water, it doesn’t contain bacteria or mineral deposits that might contaminate the air you breathe.
Ductwork systems, which are manufactured for both commercial and residential applications, can be custom-designed to output any amount of steam a house might need—though custom units may be prohibitively expensive for most home applications. And they can be costly to operate.
Steam units employ an electrical element to heat the water; when this is on for extended periods, it can rack up the energy dollars.
