Is extra humidity harmful?
When it’s cold enough to use the central heating system, most homes experience a significant drying effect that can be irritating to the nasal passages of residents, and lead to the shrinking of caulk and damage to wood furnishings. To compensate for the level of moisture being extracted from the home during the heating season, many homeowners use humidifiers which provide many health and comfort benefits. Water vapor is a by-product of gas combustion. Vent-free gas products emit a very moderate level of water vapor and that is a very positive secondary benefit of the appliance. Independent research has proven that for 99 percent of homes in the U.S., the water vapor generated by vent-free gas heating products is below the level that would cause any negative side effects.
