COOLING UNIT BUYING GUIDE
The Difference Between Wine Cellar Cooling Unit and an Air Conditioner
But many people also feel that 60 is close enough to 55, and if they are not aging their wines for extended periods of time (more than a few years) that the temperature difference won't really affect the wines. If it was just a matter of temperature that could possibly be the case. But as important as temperature is humidity. Standard AC units are built to cool the air quickly and to draw all of the humidity out of the air so that you and I are comfortable in a room. That is about the worst thing you can do for your wine. The humidity helps to keep the corks moist, as if they dry out and air gets into the bottle, you have just turned your expensive bottle of wine into an expensive bottle of vinegar.
Wine Cellar Cooling Units are designed to cool the air at a much slower rate in order to maintain the humidity in the room. In certain units you can even add a humidification component to help raise the humidity if the wine cellar is in a dry area. So it is really the combination of the wine cellar cooling unit's ability to cool down to those lower mid 50 degree temperatures and doing so without drying out the air that makes them quite different then your standard air conditioning units.