General Humidifiers

Proper humidity levels in your home reduce annoying static electricity, dried cracked furniture and wood trim, and wilting house plants. You'll feel more comfortable as scratchy dry skin, throats and and noses are soothed. Properly humidified air feels warmer allowing you to turn down your thermostat a few degrees and reduce energy costs yet still feel comfortable.
Humidity

Humans are very sensitive to humidity, as the skin relies on the air to get rid of moisture. We feel much hotter than the actual temperature when the relative humidity is high. For example, if the air temperature is 24 C and the relative humidity is 100 percent, we feel like it's 27 C out.

People tend to feel most comfortable at a relative humidity of about 45 percent. Air conditioners, humidifiers and dehumidifiers help to keep indoor humidity at a comfortable level.