Before you build · Drawing set 01
Nine cooling decisions that are cheap on paper and expensive after drywall. Fill in the room, check them off, take a one-pager to the contractor.
Title block
BYB-01
Settle these before framing
Decisions
Nine
Envelope through install
Envelope
R-20
R-30 on exterior or attic
Ambient window
50–77°F
Air around the condenser
Install
Licensed HVAC
DIY voids the warranty
Most wine cellar cooling problems are decided long before the unit gets picked, in the envelope, the sizing, and where the heat goes. Work through these nine steps while it's still lines on a plan.
Written and reviewed by
Panthaire HVAC Engineering Team · Licensed HVAC · Wine Cellar Cooling Specialists
The team that engineers APEX is the same team that ships it and answers the phone when installers call.
Last reviewed · August 20, 2026
0 of 30 items checked
Cooling can only hold what the room can keep. Insulate to R-20 (R-30 against an exterior wall or attic), put the vapor barrier on the warm side, seal every penetration, and use an insulated, gasketed door. This is about 80% of the result.
For an R-20 envelope, plan on 3.5 to 4.5 BTU per cubic foot, add about 15% for a glass door (more for larger glazed areas), and confirm with a BTU calculator before buying.
There are four types: through-the-wall (self-contained), ductless split, ducted split, and fully ducted self-contained. Match the type to your cellar and how much noise and aesthetics matter, not just the price.
Your architecture
Every cooling unit rejects heat somewhere, and that space has limits. The air around the condenser must stay roughly 50 to 77°F (10 to 25°C) year-round. Decide the cabinet location before framing.
Condenser location
A dedicated circuit, wired to code and inspected. Confirm the unit's voltage and amperage before rough-in.
Target 55°F (13°C) inside the 50–70°F (10–21°C) operating range; stability beats the exact number. Humidity is handled by the envelope, not the cooling unit. A cooling unit controls temperature, not moisture.
Keep the compressor's noise and vibration away from the bottles. Ducted architectures do this by keeping the mechanical unit out of the cellar, worth it for glass-walled cellars or any cellar next to living space.
R290 (a natural refrigerant) is replacing R410A and R134a under the US AIM Act HFC phase-down. In 2026 it is the more efficient, future-proof choice.
Cooling installation is licensed HVAC work: duct connections, electrical, condensate handling, control commissioning. It is not a DIY step for ducted or split systems, and DIY installs commonly void the warranty.
Common questions
For a well-built cellar (R-20 insulation with a warm-side vapor barrier), plan on roughly 3.5 to 4.5 BTU per cubic foot, so a 500 ft³ cellar needs about 1,750 to 2,250 BTU. Add about 15% for a glass door, and more for larger glazed areas. Confirm with a BTU calculator before buying. The figure assumes a sealed, insulated envelope, and oversizing causes short-cycling.
No. Standard air conditioners are built to hold a room around 68 to 75°F and most will not run below about 60°F, so they cannot reach or hold the 55°F a wine cellar needs. They also cool aggressively and dry the air in a way that is hard on corks. Wine cellar cooling units are engineered for slow, stable cooling in a sealed, insulated cellar.
Yes, it is the most-missed and most damaging mistake. A vapor barrier on the warm side of the insulation stops moisture from condensing inside the walls. Get it wrong and you get condensation, mold, and a cooling unit fighting a load it was never sized for. It has to go on the outside-facing side of the insulation.
Target 55°F (13°C) inside the 50–70°F range, and prioritize stability over the exact number. Humidity is held passively by the cellar envelope, not by the cooling unit. A cooling unit controls temperature, not moisture. In a properly built envelope, a stable 55°F cellar maintains a healthy relative-humidity band on its own.
The air around the condenser must stay roughly 50 to 77°F (10 to 25°C) year-round. That rules out an unconditioned garage, attic, or crawlspace, too hot in summer, too cold in winter. Decide the location before framing so the ductwork and electrical can be planned around it.
Issue for construction
A one-page set of your answers for the contractor. Then confirm the load and pick an APEX cabinet. This page is the room, not a second calculator.
Download the plan
Email required. Volume, architecture, condenser, and the nine steps.
Confirm the load
The BTU calculator matches cubic feet to an APEX model.
Browse APEX
115V/60Hz, R290, 2 years warranty.
Panthaire · Planning checklist
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How to build a wine cellar
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