Wine cellar cooling systems: self-contained, ducted or split?

An ordinary comfort air conditioner is not designed for the job, so a wine cellar cooling system is chosen from the heat load of the space, not its floor area. A self-contained unit keeps every part in one housing; a ducted system moves air to a unit outside the cellar; a split system keeps the evaporator inside and the condensing unit outside.

A common failure starts with a self-contained unit on a cellar wall whose exhaust blows into a small closed cupboard. On the first hot afternoon the cupboard warms, the unit breathes its own exhaust and may run flat out without reaching its setpoint. Nothing is wrong with the unit; its position was never part of the design.

Why not use an ordinary air conditioner?

Because comfort air conditioners are built to cool people in occupied spaces, not to hold a low, constant temperature around the clock. Many are not specified for a 12–14 °C (54–57 °F) setpoint and often dry the air strongly, which is the opposite of what a cellar needs.

A cellar asks for three things at once: a low temperature held without large swings, humidity kept in the range of roughly 60–70%, and quiet, vibration-free running. Some comfort units can be adapted, but check the manufacturer’s stated operating range before you consider one, and expect the result to be less stable than a purpose-built cellar unit. The targets behind these requirements are explained in wine cellar temperature and humidity.

How is a wine cellar cooling unit sized?

It is sized from a heat-load calculation, which adds up everything that puts heat into the cellar. Floor area alone cannot do this, which is why a small cellar with a glass wall can need more capacity than a larger enclosed one.

The inputs we use for every cellar include:

• the volume of the space and the thickness and continuity of the insulation;
• the temperature of the spaces on the other side of each wall, the floor and the ceiling;
• the outside conditions at the site, including summer peaks;
• glass area, glazing type and how much sun reaches it;
• lighting, which is small with LED but not zero;
• how often the door opens and how many people use the space;
• new bottles brought in warm, which carry heat in.

The unit is then chosen to cover the total with a sensible margin. Too large is also a fault: an oversized unit typically cycles on and off quickly, often dries the air and can hold temperature poorly. One that is too small may never catch up on a warm day. The quality of the insulation is part of the same calculation, and we explain how it is built in our wine cellar planning guide.

What is the difference between self-contained, ducted and split systems?

The three differ in where the components sit, and so in where the heat, noise and condensate end up. The comparison below summarises what each needs from the building.

System	Where the parts sit	Watch for
Self-contained	One housing in a wall opening or on a wall or ceiling	Exhaust heat and noise land next door
Ducted	Unit outside the cellar; air travels by ducts	Duct routes, insulation, condensation on ducts
Split	Evaporator inside; condensing unit remote on refrigerant lines	Line routes, outdoor position, building approval

Self-contained. Compact and simple to install, and well suited to smaller cellars. The cost of simplicity is that the compressor and fans sit at the cellar wall, so the neighbouring space must be able to take the exhaust heat.

Ducted. The unit lives elsewhere, a plant cupboard or a service area, and conditioned air is carried to the cellar and back through insulated ducts. It moves the noise and the heat away from the cellar, at the price of duct routes and the need to insulate and seal them.

Split. The evaporator is in the cellar, the condensing unit with the compressor is outdoors or in a plant area, connected by refrigerant lines. It puts the loudest part somewhere remote and suits larger loads. Its demands are the lines, an outdoor position and, in apartments, approval from the building management.

The right choice usually emerges from the building rather than from a preference. The question to ask first is where the exhaust heat can go, because the answer rules some options out. Our wine cellars are designed with that decision made early.

How is humidity controlled in a wine cellar?

By the envelope first and the unit second. A well-sealed cellar with a continuous vapour retarder on the warm side of the insulation keeps outside moisture out, so the unit has less humidity to manage. The unit’s coil then removes only what is needed.

Units made for cellars are designed to limit drying of the air, and a humidifier can be added where the cellar sits in a dry, air-conditioned or heated building. In humid regions the problem reverses: air leaking through poor seals brings moisture in, and condensation can appear on the coldest surface, often the glass. This is why the door, the glazing and the junctions get as much attention as the unit itself. For glass in particular, see our glass wine cellar guide.

How do you reduce noise and vibration from a cellar cooling unit?

By putting the loudest components, the compressor and the fans, at a distance from the cellar and from sleeping areas, and by decoupling them from the structure. Noise has three routes: through the air, through the structure and along ducts or pipes.

The usual measures are a remote condensing unit, isolating mounts, flexible connections on pipes and ducts, lined ducts and a position away from bedrooms and shared walls. Vibration also matters for the wine, so racking should not be fixed to the unit’s casing. Any quoted noise figure belongs to a specific unit and installation, and we do not generalise from it.

What changes in hot and humid climates?

High ambient heat and large areas of glass make a proper heat-load calculation essential, and it must use the actual design conditions for the site. A unit that rejects its heat into hot air works harder, and some capacity is lost on exactly the days when the load is highest.

In places such as the Gulf, the exhaust path, the quality of door seals and the amount of glazing deserve more attention than they would elsewhere. Moisture-laden air entering every time the door opens is a further load. We do not apply a rule of thumb across climates; each cellar is calculated for its own site, and for hot climates the calculation is the first step. On board a vessel the same logic applies with marine-grade equipment; see yacht wine storage.

What happens if the cooling unit fails?

Good insulation buys time, and an alarm tells you the time has started. A well-insulated cellar warms slowly. How slowly depends on its insulation, size, contents and the outside temperature, so a failure at night or while you are away need not damage the collection if you hear about it.

That is why we recommend temperature monitoring with an alert, and why access for service is planned into the design: a panel or door that lets a technician reach the coil, the filter and the condensate line without taking the cellar apart. Routine checks are described in our wine cellar maintenance checklist. Whether to fit a second unit as a backup should be decided during design.

How does Ardinart approach cooling?

ARDINART Wine Cellars designs, builds and installs made-to-measure wine cellars, cabinets and storage at its own facility in İkitelli OSB, Istanbul. We calculate the heat gain first and choose the unit afterwards, then draw the position of the unit, its exhaust and its condensate route into the design. Insulation thickness follows the calculation, and the system is selected to match it.

One example is Private Mansion No.3 in Kemerburgaz, Istanbul: a private mansion cellar with a project-specific climate system and ventilation, built in solid timber. The unit and the ventilation were part of the cellar’s design from the start. You can read how the design stage works on our custom design page, and how cooling shapes the budget in what drives the cost of a wine cellar.

Frequently asked questions

How loud is a cellar cooling unit?

It depends on the unit, how it is mounted and how far it is from where you sit or sleep. A self-contained unit on the cellar wall is the most audible; a remote condensing unit or a ducted unit in a plant space is the least. Ask for the manufacturer’s sound data for the exact model, and tell us which neighbouring spaces are quiet.

Where does the condensate go?

Cooling air produces water, and that water needs a planned route: a gravity drain with a trap, a small pump to a waste line or a unit that evaporates it. The route is chosen during design, because a cellar in an apartment or on an upper floor may have no drain nearby. A condensate line that is forgotten is a leak waiting to happen.

Does a glass wall change the cooling unit?

Yes. Glass lets in more heat than an insulated wall, so the unit’s capacity must rise to cover it, and the glass surface is the likeliest place for condensation. Insulated, UV-protective glazing and a unit sized in the heat-load calculation are designed together. A glass wall is not a problem, but it should never be an afterthought.

How often does a cooling unit need servicing?

Follow the manufacturer’s instructions, and treat an annual check by a technician as a sensible baseline. Filters and coils need more frequent cleaning in dusty or hot conditions. Between visits, read the temperature log and listen for changes. A unit that runs longer than it used to is telling you something.

Can one unit serve two zones?

Sometimes. Two zones at different temperatures need an insulated partition between them, and either two units or a ducted arrangement with separate controls. A single unit usually cannot hold two setpoints on its own. Decide early whether you really need a second zone, because it affects the cooling system and the layout together.

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The right system follows from the building, the climate and how you will use the space. Book a discovery call and we will work out the heat load with you before any unit is chosen.