I am not a smoker, thank goodness I never went down that road, but I know a lot of people who are.
One of my best friends, a guy I have known since we were in grade school together, is a cigar buff.
Personally I think cigars smell great, until you light one up, then it smells like burning animal hair. Recently my pal wanted to take his love of cigars to the next level, and started working on a walk-in humidor for his house. Basically a humidor is supposed to maintain the perfect level of humidity for maintaining the best tobacco. A walk in humidor would need a little HVAC work as well, to make sure the ventilation system was working well, and to keep the room pressurized. Since the door would open once in a while, he wanted to use the central HVAC system to create higher pressure inside the humidor. That way when the door opened the air would flow out, but not in, and all the air in the room would maintain the perfect humidity levels. We quickly found out that this was not something his central HVAC system could handle on its own, so we needed to do some building and renovating. I suggested putting a dehumidifier in the room instead, as it would be much easier. He informed me that having too little humidity is as bad as having too much, so a dehumidifier would not work. It took some consulting with experts, but finally we got the humidity and ventilation issues all settled.