In 1999 when my wife Robin and I set about re-doing our kitchen (remodeling with bulldozer !), we decided to take this opportunity to dig down 9 ft. to build a cave under the new kitchen.
Since this is a 150+ yr. old house, the entrance to it required cutting through the old granite foundation. The new cave would be isolated from the heating system of the house by about 30" of granite (note the thickness of the granite wall in photo to the right) and another 10" of cement and the ceiling with about 10" of insulation and a vapor barrier. The new cave would be primarily cooled by the ground temp but in mid winter a small heater is needed to keep it above 50F and during mid-summer an air conditioner is needed to keep it below 60F. This means a bit of seasonal fluctuation and this would have been normal in a traditional cave. In the future if I do want to keep the upper temperature more in the 52-56F range, I will use a small compressor and an evaporative loop to do this.
The finished cellar measures 15'x25' and I have isolated a 6'x15' foot room with a heavily insulated wall w/ vapor barrier and an insulated door on the North side of this space to eliminate as much solar gain as possible. This smaller room is the 'Cave' and where my cheeses age quite well. I have left the north wall of this room as bare unfinished concrete. The humidity in this room can be kept at a fairly stable 85-90% and the temp will hold at 52-54 during most of the year with no help to cool or heat. During July and August I need to use an air conditioner in the larger room to keep it down in the upper 50s and during late January a small heater in the cave to keep it at 52F. The larger room his usually much drier at about 65% and makes a good drying room for my soft ripened cheeses before they are placed in the cave.
The 'Cave', holding at a perfect 'cellar temperature' of 52-54 is ideal for my serving kegs of beer which get forced by CO2 directly up to taps on the kitchen wall. The larger room is also a great place to store my beer and wines and during the winter it holds stable at a constant 48F from November to April and is the perfect fermentation temperature for my lagers. In addition to all of this it is a great root cellar for vegetables and home canned goods.
All in all it is a pretty good traditional system ... Those that have been here for workshops can attest to that!