Living in the northeast we needed a furnace for almost half the year. Our furnace was a gas forced air unit that was about 5 years old. It was energy efficient when we purchased it and had really not had any issues. I had been researching about how a humidifier added to a furnace could greatly improve the air quality inside the house. So I called a local HVAC company to see what it would take to install one on my existing furnace. A serviceman came out the next day and explained to me how it worked. The small unit was attached directly to the air vent that sent warm air to the home. This unit was attached to a water source and then a drain hose was installed and run to a drain in the basement. The humidifier had its own control unit which let you set the amount of humidity you wanted in the house and it also had an on/off switch. This was to enable the unit to be on in the winter and off during the summer. I decided to go ahead with adding a humidifier to my furnace and it only took a couple hours to install. I noticed a difference almost immediately. The air felt not as dry and more comfortable. I especially noticed having the humidifier while sleeping. I used to wake up with a dry mouth and nose. Now the air was moist enough to make if comfortable for sleeping. I am really glad I had the humidifier added to my existing furnace. It was a very wise investment in comfort!