The THUMD300 Trane humidifier is a large bypass unit that provides the right amount of moisture in every room, with a capacity of 16.8 gallons per day and up to 4,000 square feet. Temperature is just one factor in total home comfort, especially in dry weather. Trane’s trusted humidifiers can adjust from summer to winter to provide the right amount of moisture to the air in your home, and can help alleviate allergy symptoms. It’s not just comfort. It’s relief for your skin.