The most cost-effective is a self-contained unit or "through the wall" system. This type of unit is just what it says. The evaporator and condenser are built into one unit which sits in the wall and vents from the cellar to the adjacent room. For this system to work, you must have a room next to the cellar that is at least twice the size of the wine cellar you are cooling and has heat and air conditioning. The unit will give off heat as it removes that heat from the cellar. You must also be OK with the unit showing through on the wall of the next room.