If you're thinking of adding a custom-built wine cellar, here are some important components
Plastic sheeting between the cellar's exterior wall and insulation keeps humidity and condensation from seeping into a home's walls. Use at least 1/4-inch plastic.
The more insulation, the less work for the chiller. Use foam block insulation rated a minimum of R-21.5 in the walls and R-46 in the ceilings.
Solid redwood won't rot or warp. Be careful if giving it a decorative stain; uncured finishes can emit gasses that might taint the wine.
Use fluorescent or thermally insulated lights. Otherwise heat from the lights might cause condensation that leads to a short circuit, or even a steady drip into the cellar.
SPLIT COOLING SYSTEM
This refrigeration unit for high-end cellars puts condensers and vents outside the house so the system runs quietly with less vibration.