Usually I deal with high end clients, who have serious money to invest in their collections. I guess this is why most rare book collections are owned by the ultra-wealthy because no one else has that much money to throw away on something they don’t need. As much as I love books, they don’t feed your family or help you survive, they are a luxury item. That said, if you have books or comic books that you want to maintain, but don’t have mountains of cash to waste, you can use your HVAC system or a few small tweaks to achieve great results. The biggest piece of advice UI can give you is to worry about consistent air quality for your collection. That goes beyond temperature control, because within a fairly wide range your books will be fine as long as the temps are stable. It’s more important to focus on air quality, and that means keep your books in their own space and not out in the common areas. You’ve seen bookshelves in peoples living rooms, and that is where dust piles up because of heavy traffic and lower air quality. After clean, consistent air quality, you need to focus on the levels of humidity your books are exposed to. It is more important to those people in the south to have a dehumidifier for their books, but in general I think everyone should have one. Books are so sensitive to moisture, it is worth the small expense to get a dehumidifier to keep them safe, sound, and dry.