A properly built cellar is really a house within a house, all the way up to its tightly fitting front door. Keeping the carefully conditioned air behind that door takes a knowledgeable builder and meticulous construction detailing.
“People think they can cheat on the construction of the room,” says Dena Rose, of D’Vine Wine Rooms, based in Wall, New Jersey. But you can’t. Her firm has found mold in poorly constructed cellars, she says. “We had to get those bottles out of there, basically rip out the walls and start again.”
Savvy builders insulate the room carefully and install a vapor barrier to prevent water from condensing inside walls. “Remember,” says Charlie Griffiths, of Vigilant, Inc., a New Hampshire–based specialist, “if the power goes down for three, four, or five days in a well-insulated, well-built wine cellar, it’s not going to be the end of the world. As long as you’re not going in and out of there all the time, the temperature will creep up slowly.”