Compressor units cool down by using a refrigerant that is compressed to turn the air cold. A fan then blows air across the coils, which is where the cooler air comes from.

Thermoelectric units cool down by utilizing a process known as the "The Peltier Effect" which draws heat out of one metal and into another, with the use of an electrical current. Thermoelectric cooling doesn't create cold air, but rather it pumps the hot air out.

Because thermoelectric cooling uses less moving parts, it is typically quieter than a compressor, and it minimizes vibrations, which can be harmful to wine. Thermoelectric coolers also consume less energy than compressor units, so they cost less to operate. The only down side to thermoelectric units is that they are generally not as powerful as compressor units, and can not get as cold as their compressor counterparts.