This case study describes how IWA’s design and engineering team planned and delivered a residential temperature-controlled wine cellar for a collector storing 1,000+ bottles.
The space is located under a staircase, has an L-shaped footprint, and shares a wall with a main living area. The priorities for the project are bottle capacity, stable storage conditions and quiet operation inside the home.
Most custom wine cellar projects start with the same questions: how much wine is being stored, what space will accommodate the bottles and how to achieve the homeowner’s design aesthetic. In this project, 3 constraints drive the key engineering decisions, as follows:
The designated area is a 150-square-foot L-shaped room beneath a staircase. This type of footprint creates narrow runs and corners that reduce usable storage. Therefore, the racking layout is designed to use wall space efficiently while keeping bottles accessible.
The cellar shares a wall with the home’s primary entertainment room. Because the space is adjacent to a living area, the cooling strategy needs to minimize perceived noise indoors. This requirement narrows the available equipment options and influences where major mechanical components can be located.
The room includes an exterior wall, which exposes the cellar to wider temperature variations. The tallest height is 10 feet, and the shortest height is 5 feet. When calculating the cellar’s thermal load, we consider the construction of the cellar, including the insulation and amount and type of glass (if any); the desired temperature inside the cellar; the peak temperature outside the cellar; the amount of cold-side ducting (if any); and other sources of heat, such as lighting and appliances, inside the cellar.
The project begins with a consultation to review the size and mix of the wine collection, the homeowner’s priorities and the room’s constraints. After the consultation, the design team produces CAD drawings to translate the layout into build-ready plans for the wine racks, wine cellar construction guidelines and a recommended cooling system for the refrigeration, including:
The design uses label-forward metal racks that are low profile, thereby emphasizing the bottles and providing increased density in narrow sections while keeping the room visually open. A modular system is useful in under-stair and L-shaped rooms because it can be adjusted to fit short runs and non-standard wall segments. The final layout supports approximately 1,050 standard Bordeaux bottles.
To address the noise constraint, the project uses a CellarPro 8000Sx split system, which produces 6713 BTUH at 55°F. In a split configuration, the evaporator is located inside the cellar and the condensing unit is located outdoors, which reduces noise and heat inside the home.
The system capacity is selected to match the cellar’s calculated thermal load, with the goal of maintaining optimal temperature and humidity inside the cellar. Using CellarPro’s cooling unit calculator, we determine the thermal load of the cellar is 4545 BTUH, and based on this sizing, the recommended cooling unit is a CellarPro Split 8000Sx. The 4545 BTUH load accounts for the heat transfer that occurs through the concrete floor of the cellar.
To facilitate airflow inside the L-shaped cellar and ensure uniform conditions, the evaporator placement was optimized to facilitate cross-room air circulation, preventing stagnant 'hot spots' in the narrowest sections of the under-stair area.
The design specifications for the conditioned space include:
The finished cellar provides on-site storage for the customer’s full collection, with room to grow, in a dedicated, conditioned space. The mechanical noise and heat from the cooling unit are moved to the exterior, where it won’t be noticeable in the adjacent living area.
CellarPro 8000Sx Split
Sizing is based on the cellar volume, construction and temperatures inside and outside the cellar. Split system removes noise/vibration from living areas.
6-mil Polyethylene
Makes the cellar airtight, to prevent mold and allow the cooling unit to maintain 60% humidity.
R-19 (Walls)
Offsets heat transfer from interior and exterior walls.
Label-Forward Metal
Modular assembly allows for efficient racking throughout the cellar. Label-forward and low-profile design puts the emphasis on the bottles.
For under-stair wine cellars in finished homes, the biggest drivers are usually the same: space efficiency, mechanical placement and cellar construction. If the cellar shares walls with living space, a split system or other remote mechanical approach can materially reduce indoor noise. If the room has exterior exposure, insulation quality, vapor control and door sealing typically matter as much as equipment selection.
If you are planning a wine cellar in an under-stair or other constrained space, start with the room dimensions, wall construction, amount of glass and temperatures inside and outside the cellar. These variables will determine the racking layout and the cooling approach early, before construction begins, and will drive the overall budget of the project.
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