Storing my brother’s guitars and keeping the air quality perfect

My brother is a wanderer and a hippie at heart. He frequently will travel to a new location with his backpack and one guitar. He then will squat on someone’s couch, play music and work an easy part time job. An ideal hippie would only own a few items. My brother just can’t part with his vast guitar collection. Since he has no real or stable home, I store the guitars for him. I have to say, I like the look of the guitars. If he ever gets short on money, I plan to buy and keep them. I have a whole room set up for his collection. Each guitar has its own shelf with a built in padded stand. I then have a separate ductless HVAC unit for just that room. You can’t let the guitars have no heating or air. It would totally mess up the wood. Air quality is really the biggest issue with the guitars though. If the indoor air quality gets too dry, the wood could split. If the air conditions are too moist, the wood swells. I don’t want messed up guitars because I am not watching the air quality. So not only do I own ductless HVAC, but I have a dehumidifier and humidifier for the room. In the winter I run the heater with the humidifier and the summer has cooling and a dehumidifier working. The guitars are in perfect condition. They actually look better now in my opinion. I get them cleaned and tuned once a year. I like to think the guitars are happier living with me than my brother.

indoor air quality