Freestanding: Also referred to as console humidifiers, freestanding units are portable and don't integrate into your home's HVAC system. Bypass: These integrated systems divert warm air from the home’s HVAC system and pass it through a wet pad, then send the humidified air back into the home. These integrated systems divert warm air from the home’s HVAC system and pass it through a wet pad, then send the humidified air back into the home.