I have a sizable collection of very old books. Some of these editions are extremely rare and worth quite a bit of money. I have spent the past twenty years searching book stores, flea markets, estate sales and antique stores for books. I sometimes purchase volumes simply because the leather bindings and parchment pages appeal to me. I take very good care of my collection, and never handle them without wearing gloves. The oils from my fingertips could cause irreparable damage. I am very conscientious about temperature and humidity control. Excess moisture could lead to mold and mildew, while insufficient humidity might cause the pages and bindings to crack and crumble. I have invested into a modern heating and cooling system with zone control. This allows me to target and control the conditions in the room that houses my collection. Along with the heating and cooling system, I’ve installed both a humidifier and dehumidifier. In the winter, with the furnace running, the air tends to become overly dry. The humidifier introduces necessary moisture and gives me the capability to determine relative humidity. In the summer, the central cooling system handles the heat, but is not effective against excess moisture. The dehumidifier combats the sticky feeling and combats the growth of harmful bacteria. Although the upgrades to my HVAC and air quality were expensive, my home is more comfortable and much healthier. Plus, the humidifier and dehumidifier promote more conservative thermostat settings, and I spend less on my monthly energy bills. I am thankful that the integrity of my rare book collection is protected.