Wine Cellars Require Special Skills, Training
Installing a wine cellar is not for the faint of heart - or wallet. Cellars can range from 60 to 600-plus square feet and often cost anywhere from $8,000 to $30,000. Those who can afford this expense usually turn to contractors who have specific training in the design and installation of wine cellars. Just because a contractor may know how to install an air conditioning system does not mean he is familiar with the special conditions required in a wine cellar.
These requirements include precise temperature and humidity control, which is achieved by installing extra insulation, vapor barriers, door seals, and specialized refrigeration equipment. A properly designed wine cellar will ensure the homeowner's wine collection will be kept at the correct temperature and humidity for years. An improperly designed wine cellar can result in ruined wine collections, moldy walls, and water damage.
WHEN THINGS GO WRONGLarry Kendall has seen more than his share of improperly designed wine cellars. As the president of Wine Environments Inc., Santa Ana, Calif., he designs the refrigeration equipment needed for wine cellars (sold through Vinotheque/Whispercool). Basically, Kendall uses stock Tecumseh condensing units and modifies them by adding hot gas bypass and controls. He then places the unit on a base with its own enclosure.
The outside unit is small and unassuming, and he suggested that the indoor unit be hard ducted. "To me, flex duct is a dirty word," said Kendall. "First of all, it reduces the capacity of a given system, and second of all, it doesn't offer much in the way of insulation."
Kendall also designs and installs refrigeration equipment for the occasional specific wine cellar and is more than happy to dispense advice on what to do and what not to do. He notes, however, that getting the contractors to listen can be a bit of a challenge.
Ever the consummate storyteller, Kendall can relate story after story of wine cellars that were improperly installed. For example, there's the Washington, D.C., doctor who noticed the ceiling in his wine cellar was sagging a bit, so he poked his finger up there and the whole ceiling came down on his head. The problem? The vapor barrier was installed in the wrong place.
"The installing contractor put fiber glass insulation in the ceiling and walls, then put the vapor barrier on the inside. Moisture that tried to go through the wall was stopped by the vapor barrier, saturating the fiber glass insulation, and causing a big pool to form up in the ceiling," said Kendall. "There were probably 10-15 gallons of water that came crashing down, along with the ceiling, on top of this guy's head."
It is because of situations like these that Kendall believes changes need to made in the industry. "One supplier of systems for the wine cellar trade has presented a 1/2-horsepower product as being capable of producing 8,800 Btu cooling capacity. The same supplier had no idea what condensing temperature the machine was designed for. I would like to see an ARI standard as well as a certification program, which would help all parties involved."
KEYS TO SUCCESSOne of the mistakes contractors can make when constructing a wine cellar is to use air conditioning equipment. According to Kendall, the main problem is that equipment dries out the air in the room too much. "We want to keep the humidity around 60-70 percent. Most air conditioning equipment is designed to keep humidity levels around 50 percent."
In addition, because air conditioning coils have 16-18 fins per inch, as opposed to the 12-13 fins per inch in refrigeration equipment, there's a danger of the coil freezing up.
"Sometimes a manufacturer will put in some kind of defrost control or low-pressure control but that defeats the purpose of the system."
Even if refrigeration equipment is installed, there's still a possibility that it hasn't been specified correctly. In some instances, packaged equipment is installed, rather than the preferred split system.
"We have replaced six packaged units in the last 18 months. In all but one case the cooling was being accomplished properly but noise and rejected heat into a living area made the systems unacceptable to the customer."
When constructing a wine cellar, vapor barriers, door seals, insulation, equipment access, and proper installation are the most important and least considered aspects.
"In many instances, builders treat the rooms as rooms that are simply cooler than the others in a house," said Kendall.
Ideally, the room should be constructed as a wine cellar rather than converting an existing room in a house. There should be a proper vapor barrier on the exterior wall of the room, and the vapor barrier should be as far from the cold room as possible. If it is installed inside the room, Kendall warned, there is the risk of attracting moisture in the insulation and wall cavities (remember the Washington, D.C., doctor?), which will ultimately cause mold to propagate. The rule of thumb is: no vapor barrier is better than a vapor barrier installed on the inside wall.
Another problem that Kendall often encounters is improperly piped and wired refrigeration systems. "I am going to visit a cellar this week that has been installed by a contractor who can't figure out a simple three-wire control system. The builder and the owner are upset, but the problem is lack of basic technical skills." Another issue that Kendall said he sees far too often these days.
Even the temperature in the house can affect the temperature inside the wine cellar. Kendall usually bases his systems on a 75°F ambient temperature in the surrounding house and a 55° temperature in the wine cellar. If the contractor doesn't take the house temperature into consideration, there can be problems.
"We have many customers in Palm Springs, and they'll close up their houses for the summer. If they set the thermostat for 85° or 90° while they're gone, then the temperature differential has gone from 20° to 30° or 40°. That's not a problem as long as the person who's designing the wine cellar recognizes that going in and provides adequate systems and insulation. The condensing unit also needs to be able to deal with the high-ambient temperature."
As you can see, there are numerous issues to consider when designing a wine cellar. For these reasons, it's best to leave the job to someone who is well versed in wine cellar requirements, or else obtain the necessary training before attempting an installation. Either that, or risk facing an irate customer who's just had a ceiling cave in on his head.
Publication date: 06/26/2006