First you want to consider the size of the space you are fitting the cooler for by measuring the height, width and depth. You'll want to select a model that just fits into the allowable space. For undercounter and built-in wine coolers you will need a front exhaust model. Free standing units can be any size you wish.
The number of bottles your wine cooler will hold depends on your preference and the size of your collection. However a rule of thumb is to go larger than you think. If you are considering purchasing a wine cooler, you are evidently into wine and you can expect that your collection will inevitably grow larger over time.
Will you be storing only red wine or only white wine or both? If it's only one or the other, a single zone wine cooler will suffice. If it's both, then you will need a dual zone cooler. Single zone or dual zone means each zone maintains it's own temperature. Red wines are kept at 50 to 55 degrees Fahrenheit and humidity settings are 60-75%. White wines and champagne do well at 45 degrees Fahrenheit. If you plan to store wine for longer than a few months we recommend using a hydrometer to measure the humidity level.
Wood or furniture style wine cabinets are becoming very popular. If you are considering putting the cabinet in your living room for instance, you need to determine the color of the wood that will blend in with the rest of your decor. Expect to find most wine coolers are fitted with chrome/wire racks or wood racks. Coolers of higher quality are generally fitted with wood or aluminum racks, including solid wood exteriors.
Locking models are very popular with parents and grandparents. You will want to protect your collection from children or anyone you don't want getting in your wine collection. Remember if you lock your cabinet you won't be missing any treasured bottles when you come back from that week-long vacation. You will have complete control of your wine or champagne collection.
Thermoelectric wine coolers use what is known as the Peltier effect to keep bottles cool. Thermoelectric units are more adequate for red wine but depending on ambient temperatures, they may be insufficient for chilling white wine. Traditional compressors give refrigerators their reliable cooling ability. However the cycling of the compressor can cause some slight vibration which can disturb the sediment in the wine. Most wine coolers using a compressor for cooling are very reliable and are generally on the quiet side, like a new kitchen refrigerator.