Thermowood Cold Plunge Ø90 cm with AISI 316 Stainless-Steel Tub

Thermowood and stainless-steel cold plunge: a single-person format to configure precisely

This round outdoor cold plunge is designed for one person. Its character comes from the combination of two clearly published materials: a Thermowood outer cladding and an inner tub in AISI 316 stainless steel. It suits a single-person cold-immersion project in a garden, on a terrace or next to a sauna. The supplied package includes filtration, circulation and a WiFi Poolex SpaWer O’SPA heat pump for heating and cooling; the exact technical references are still to be confirmed.

Photographs of the model show a tall, cylindrical tub, a wide timber rim and a small seat step inside. This layout favours an upright posture and a small footprint rather than a long, bath-shaped plunge.

Dimensions and capacity

The available documentation does not state whether the 90 cm is the inner or outer diameter. Water volume, usable depth and empty weight are not published either. If the tub has to pass through a narrow opening or sit in a made-to-measure recess, ask for a dimensioned drawing before you build.

These missing figures also matter for the base: it must be designed for the tub, the water, the user and all equipment, rather than working out the load from the diameter alone.

Thermowood outside, AISI 316 inside

The Thermowood gives the tub a timber face that sits naturally with a deck or sauna. The AISI 316 inner tub has a continuous metal surface that is easy to reach for cleaning. Close-up photographs show a satin finish, a round base and a small timber element against the inner wall.

This construction clearly sets the model apart from a fibreglass or polypropylene tub. It does not remove the need for proper care, though: the final manual should specify how to clean the stainless steel, which products are compatible and how to protect the outer timber finish.

Heating and cooling with a Poolex O’SPA solution

The package includes a WiFi Poolex SpaWer O’SPA heating and cooling heat pump, which is also visible beside the tub in one of the product photographs. The manufacturer’s O’SPA datasheet confirms three functions that matter here: heating, cooling and Wi-Fi control.

The range includes several models at 3, 5 and 7 kW. They differ in flow rate, current, dimensions and cooling range. No product source, however, identifies the exact model supplied with this tub. It would therefore be misleading to quote a single output, consumption, minimum temperature or cooling speed here.

Your quote should state at least:

• the exact heat-pump model;
• the intended heating/cooling mode;
• the required flow rate and the specification of the included circulation pump;
• the power supply, protection devices and the layout of the included connections;
• the operating limits according to outdoor temperature;
• the unit’s location and required clearances.

The advantage of the supplied active circuit is that the water can be set and held within the capabilities of the installed model. The package contents are confirmed, but the plumbing and electrical layout must follow the manuals of the equipment actually delivered.

Filtration and what the set includes

The configurator defines the included package for this model:

• cold plunge with Thermowood outer structure and AISI 316 stainless-steel inner tub;
• integrated drain valve;
• filtration system / filter;
• circulation pump;
• equipment cabinet;
• timber steps;
• the connections the system needs;
• brushed stainless-steel interior finish;
• WiFi Poolex SpaWer O’SPA heating and cooling heat pump.

Brands, models, flow rates and other technical data for the filter and circulation pump are not published. The model, output, temperature range and exact performance of the O’SPA heat pump are not stated either. The timber lid seen in the photographs is not presented as included, because this has not been confirmed.

Preparing the installation

Provide a level, stable and load-bearing surface, with no slope that could put lasting stress on the structure. The layout should allow for the tub, access, opening and storing the lid, and the technical space around the pump, filter and included cabinet.

Drainage must carry water away from the base and from buildings. Connections must stay accessible so you can check for leaks, clean a filter or drain the circuit. Any heat pump must be able to exhaust air and must not be enclosed in a cabinet its manual does not allow for.

The O’SPA range datasheet specifies a single-phase 220–240 V / 50 Hz supply. Cable size, RCD protection, earthing and siting near water must still be specified by a qualified local electrician for the exact model delivered.

This is a simple product with no variations. The configurator first shows the mandatory confirmation of the included package, then the UK delivery zones. Responsibility for unloading and positioning should still be set out in the order confirmation.

Use, water and maintenance

The routine should be set for the included circuit and the models actually delivered. A tub filled for a short period is not maintained in the same way as an installation that keeps its water with circulation and filtration. Before commissioning, ask for a protocol covering surface cleaning, daily filtration, water parameters, approved products, water changes and winterising.

Do not simply copy a routine written for another tub. The included filter, circulation pump and heat pump must be drained or frost-protected according to their own manuals. Permanent access to the equipment means you never have to move a full tub for routine work.

Why choose this model?

For a wider comparison between a simple tub and a chilled system, see our guide to ice baths and cold plunges. Before ordering, ask for the exact equipment models, the dimensioned drawing, the filled weight and the installation requirements: these are what turn the product into a project that genuinely works.