A dry indoor climate due to low humidity causes a variety of discomforts--from increased risk of colds and flu, dry skin and even nose bleeds. A humidifier helps add moisture back into the air. The cold, dry air of the winter months makes it easier for the flu virus to survive, thrive and pass from person to person. Because a humidifier keeps indoor air moist, consider using one -- especially during the winter months -- in addition to getting flu vaccinations for everyone in your family.