A.Richard M. Gold, author of How and Why to Build a Wine Cellar, responds: A garage, unless it’s underground, is the worst place for a wine storage room, because it experiences great temperature swings. Wine storage requires a temperature of 55°F +/- 5°, with infrequent and gradual temperature changes.
The best place for a wine storage room is in a basement. If the home lacks a basement, the homeowner can buy a self-contained storage chamber, which has a built-in compressor and looks like a piece of furniture. These are available from International Wine Accessories in Dallas (800/527-4072) and the Wine Enthusiast in Pleasantville, N.Y. (800/356-8466).
If the home has a basement, the wine storage room is best located at an outside corner, preferably on the north side. The walls and ceiling of the wine cellar should be heavily insulated. The basement floor should be at least 6 feet below grade and should be uninsulated, so that it can serve as a heat sink into the deep-soil temperature. If the climate is not too hot, a wine cellar can be passive (without an air conditioner). If mechanical cooling is needed, use an air conditioner designed for wine cellars. (Air conditioners designed for bedrooms will freeze their coils at 55°F.) Wine should be stored at 80% humidity, which can be provided by a plastic bucket full of water with a wick towel hanging over the side.
If the customer insists on devoting an above-ground room to wine storage, it can be done. The walls, ceiling, and floor should be very well insulated, and an air conditioner or cooling unit (the type used for walk-in coolers) should be installed.