Contrast Therapy Suites: Traditional Sauna, Cold Plunge and Rest, Designed as One

How a contrast circuit works

• Heat: 10–15 minutes in a Finnish sauna, steam room or infrared room.

• Cold: a short plunge, ice fountain or cold drench shower.

• Rest: a few minutes in a calm relaxation area, with water to drink.

• Repeat: usually two to four rounds.

We lay out the space around this loop: heat, a shower, the cold, then rest. Short walking distances, non-slip floors and somewhere to sit between rounds make all the difference, so moving from hot to cold to calm feels natural, safe and unhurried, and every part of it is easy to keep clean.

Where a contrast suite can go

We install contrast suites in spare rooms, basements, garages, pool halls and garden buildings. Each space comes with its own constraints:

• Basements need tanking, sound drainage and fresh air brought in from outside.

• Upstairs rooms need the floor loading checked, because a filled plunge is heavy.

• Garden buildings need insulation, a weatherproof envelope and a sensible supply run from the house.

We look at the space first and design the suite around it.

What a suite can include

• Heat: traditional Finnish or aufguss saunas, built bespoke or from premium modular kits in nordic spruce, thermo-aspen, alder or cedar, with electric or wood-fired heaters sized to the cabin. Steam rooms, hammams and infrared rooms can be added.

• Cold: single or twin cold plunge pools, freestanding or built-in, in stainless steel, tiled concrete or acrylic, with dedicated chillers holding the water between 3°C and 15°C. Ice fountains, drench buckets and snow rooms add variety.

• Water: filtration, UV and ozone treatment to keep plunge water clear, plus rain, mist and experience showers, floor drains and tanked wet zones between hot and cold.

• Rest: a relaxation area with heated loungers, a hydration point, quiet lighting, ventilation and controls to finish the sequence.

• With a pool: many suites sit alongside an indoor pool, sharing plant and air handling.

Getting the sauna right

A good sauna depends on things you never see. We size the heater to the true heated volume, adding allowance for glass and stone. We put the air inlet low near the heater and the outlet high on the opposite side, so the air moves and the heat feels even rather than harsh. Behind the timber cladding sit insulation, a foil vapour barrier and a ventilated cavity. These protect the structure of your home from heat and moisture. Bench heights, stone mass and heater position are set so the löyly lands softly on the upper bench.

Getting the cold right

A cold plunge is only as good as its plant. We match the chiller to the water volume, the room temperature and how often you'll use it, so the water returns to temperature quickly between sessions. Filtration and UV mean you change the water occasionally, not constantly. The chiller and pumps go where they can be serviced easily and where their heat and noise won't disturb the space.

Services and compliance

Larger sauna heaters often need a dedicated circuit, and sometimes a three-phase supply. All electrical work in a sauna follows BS 7671 (Section 703) and is notified under Part P. Drainage, ventilation and any structural work are coordinated before anything is built. Planning the electrics and drainage for the sauna and plunge together is cheaper and neater than adding one to the other later.

Private suites for homes

A home suite can be as compact as a sauna, a plunge and a shower in a basement or garden building, or as complete as a full thermal floor alongside an indoor pool. We plan it around your space, your routine and the people who will use it.

Suites for wellness businesses

Social saunas, gyms, hotels and recovery studios are building hot–cold circuits as a core offer. We design for throughput and timed sessions, with commercial heaters, chillers sized for repeated use, water treatment for high bather loads, and safety features such as timers, alarms and clear signage. See our Hotel Wellness page for more.

Why one designer for everything

A contrast suite can stand alone or sit alongside a swimming pool, steam room or gym. When we design them together, the plant room, electrics, drainage and ventilation are planned once. That avoids clashes on site, lowers both build and running costs, and gives you one point of responsibility from design to handover.

What makes a good contrast therapy suite

You can see the quality of a contrast suite in its details, and feel it in use. The sauna should have a heater sized to the true volume of the cabin and enough stone mass to give soft, lasting löyly. It needs proper airflow so the heat stays even from floor to upper bench, and well-seasoned timber that stays comfortable to touch. The plunge should have a chiller that brings the water back to temperature quickly between sessions, and filtration and UV that keep it clear without constant water changes. It also needs an insulated lid to hold the cold. Around both, the room has to cope with heat, moisture and water: hidden insulation and vapour barriers, tanked floors with good falls to the drains, and ventilation that keeps condensation off the walls. The best suites also feel good to move through, with a shower between hot and cold, non-slip floors and somewhere to rest. And everything should be easy to clean and service. A cheaper set can look similar on day one, but the difference shows within months, in how the heat feels, how clean the water stays and how well the building holds up.

Frequently asked questions

What is the minimum for a hot–cold suite?

A sauna, a cold plunge or cold shower, and somewhere to rest. Everything else adds variety and capacity.

How much space do I need?

A compact two-person sauna and a plunge can fit in roughly 6–8 m², with a shower close by. Larger family suites with a rest area usually need 15 m² or more. We'll advise once we've seen the space.

Electric or wood-fired?

Electric heaters suit most homes and are easy to control. Wood-fired heaters suit garden buildings where a flue is possible, and many people prefer the feel of the heat. We'll talk you through the trade-offs.

How cold can the plunge get, and what does it cost to run?

Our chillers typically run from 3°C to 15°C. Running costs depend mainly on insulation, a good lid and the room temperature. We design for all three.

Do I need planning permission?

An indoor installation usually doesn't. Garden buildings, listed properties and conservation areas may need it. We advise on this during design.

How long does installation take?

A suite in an existing room typically takes a few weeks once the design is agreed. Basement or garden-building projects take longer. We'll give you a programme with the design.

Can you add a suite to an existing pool?

Yes, and it's often the most efficient project, because the plant room and air handling can frequently be extended.

Is contrast therapy suitable for everyone?

Not always. People with heart conditions, high blood pressure, or who are pregnant should take medical advice first. Commercial operators should use a health declaration before first use.

Start your contrast therapy project

Tell us about your space. Send a few photos and the approximate dimensions of the room, and we'll come back with a suggested layout, initial ideas and next steps.

Explore more: Finnish saunas · Cold plunge pools · Steam rooms · Hotel and commercial wellness suites