If you find the humidity in your cellar is too low the simplest and cheapest solution is to add a bowl of water. You can add a towel to the bowl to act as a “wick” to increase the humidity level even further. For a more glamorous (although not better) solution there are many artistic table-top humidifiers available. Simple and affordable, they can dress up your wine cellar, and add the functionality of humidity to the environment at the same time. Conventional wine refrigerating systems do not offer a humidity factor, when in actuality it is a very crucial step in preserving your wine collection. A split air system may have a humidification module available. If you have a humidifier in your cellar you will periodically need to manually add distilled water to the unit. Do not use tap water as is can encourage fungal growth.
This is just a sample of the information available in “How To Build A Wine Cellar“