Maintaining the ideal indoor air humidity should be a priority for every homeowner, no matter what part of the country you live in. Indoor air that is too humid or too dry can have negative effects on your health, comfort, and the efficiency of your heating and air conditioning unit. Relative humidity is the amount of water vapor present in air, expressed as a percentage of the amount needed for saturation at the same temperature. As temperatures go up or down, the capacity of the air to hold water changes. It can be difficult to manage the indoor air humidity throughout the seasons, so here are some tips from the heating and air experts at Quality Plumbing & Heating, Inc.