Wheels,
Welcome to the forum - this is a great place to get answers, trade ideas, and make cheesy jokes.
I would encourage you to focus primarily on temperature rather than humidity. Keep in mind that a small cooling unit, like a wine refrigerator with the proper temperature range, or a small refrigerator with a controller on it, will consume only a very small amount of electricity - far, far less than you will consume by using the A/C. Humidity can be dealt with in several ways:
1) Ultra-low-tech solution # 1: if you are mostly working with semi-hard or hard cheeses, you may be able to more or less ignore humidity. I often do nothing to control humidity in my "cave" (a second-hand wine-cooler with temperature control; cost me all of $100), so it hovers around 50%. When I make a Lancashire or a Gouda or an Asiago or such, I often just let it start aging in the cave, with the rind drying out, for two to three weeks. Then I vacuum-bag the cheese (or you could wax it) - this stops it from drying out further, and in fact the moisture will tend to equalize throughout the cheese so that the rind is no drier than the rest. While very few cheeses are traditionally aged in a sealed condition (e.g., wax), I find that quite a few age just fine this way - even some parmesan / romano types that I've made. One advantage of this approach is that you rarely have to deal with unwanted mold. The greatest danger of this approach is that the surface of the cheese will crack as it dries out, so you may want to add in #2:
2) Ultra-low-tech solution # 2: put a bowl or tray with some water, and hang some cheesecloth from the shelf above so that one end is resting in the water. Using this method will not give you the optimal humidity - I get to about 70% this way - but it does raise the humidity to where you can avoid problems with cracking as the rind dries for most cheeses. And for those where you really do have to have the optimal humidity - especially the camemberts and blues and such - see #3:
3) Ultra-low-tech solution # 3: use ripening boxes - a plastic box or tub with a lid that can be left slightly ajar. You could put some water, or even some KCl brine in the bottom, but I find that the cheese itself exudes enough moisture to keep the RH up as needed. As long as you are seeing moisture beads on the walls / lid of the container, it is good. I use cheapo plastic storage containers from the discount store for my camemberts, and a Tupperware cake-carrier for my large gorgonzolas. These do take up more room in the cave, of course, but with the camemberts, I only keep them in the cave for 7-10 days; once they are well covered with PC fuzz, I wrap them in cheese-ripening paper and put them in the cold fridge; I find the slower ripening gives better results. For my gorgonolas, once they are as blue as I want them to be - usually 6-8 weeks - then I cut them into wedges and vac-bag them (light vacuum); they still continue to develop flavor, but don't continue to blue up. They turn out really well.
4) If none of the above works for you, there is always the high-tech solution - get a mister with a controller. Biggest issue with these, from what I read on this forum, is moisture collecting on the walls of the "cave."
One last comment - I hear you on the space issue. But a small to medium-sized wine fridge will take up no more room than a wine barrel, and the top can serve as a shelf. For me, this has worked great - I keep (and use) my cheese press on the fridge, along with some odds and ends of supplies. I've attached a picture showing this below - this is an old picture, with the first press I made, only a few cheeses in the cave, and the original wavy metal shelves; you can also see a bowl of water in the bottom for a little extra humidity. Since then I've made a new press (as shown in my avatar), changed to wooden shelves, and added quite a few more cheese to the cave.
