Spas, cold plunges & contrast therapy · Fennwater & the Gorge road

One hundred and four. Forty-six. Repeat.

Thermal Bay builds the hot and the cold and the circuit between them — spas that hold 104°F without fighting their own chemistry, plunges chilled to a steady 46, insulation and covers engineered like the equipment matters. On a small body of very hot or very cold water, it is all that matters.

The Hot Soak

$18,400installed, from

  • Seven-seat spa, therapy seating sized to you
  • 104°F held to a half-degree
  • Full-foam insulation & fitted cover
  • Salt-ready sanitation
  • Weekly check at $89 / month

The recovery room: jets where your shoulders actually carry the week, heat that holds itself.

The Gorge favourite

The Cold Plunge

$14,900installed, from

  • 46°F steady, chiller-driven
  • 39°F training mode on a switch
  • Insulated shell & sealing lid
  • Ozone + UV sanitation
  • Weekly check at $79 / month

The cold that wakes you all the way up — sized for two, chilled for one mission.

The Contrast Pair

$29,700installed, from

  • Spa and plunge sharing one plant
  • Three-step changeover path
  • Drainage & robe hooks planned in
  • One controller, one app, one log
  • Weekly check at $119 / month

The circuit: hot, cold, repeat — the Gorge has sworn by it for a century; we made it plumbing.

How the circuit works

Contrast, engineered

Hot water at 104 is the hardest chemistry in the yard — sanitizer works faster and burns out faster, and a spa that fights its own temperature fights everything else. Cold at 46 is the hardest insulation problem. The pair of them is a plant room with a plan: one controller, one log, one weekly visit, and temperatures that do not wander.

1

Heat

A spa sized to the people using it — jets at the shoulders that carry the week, 104 held to a half-degree by the controller, not by hope.

2

Chill

A chiller matched to real gallons and summer shade, holding 46 with a 39 training mode on a switch — no ice trays, no garden-hose rituals.

3

Changeover

Three steps, a handrail and a path that drains: the circuit designed as movement, not an obstacle course you improvised.

4

Log & look after

One app reads both bodies — temperatures, sanitizer, pump hours — and one weekly visit keeps them honest through the Gorge winter.

What we do

What Thermal Bay builds

Spas that hold their temper

Spas that hold their temper

Full-foam insulation, a cover that actually seals, and sanitation sized for hot water’s burn rate — ozone and UV carrying what a residual alone would struggle with at 104. Therapy seating is drawn around your shoulders and your spouse’s, not a showroom floor plan, and the jet count comes from the people who will sit in it.

Cold plunges, chilled properly

A plunge is a chiller with a tub attached, and the chiller is the engineering: matched to gallons, shaded in summer, holding 46 through a Gorge August. Insulated shell, sealing lid, ozone and UV — because a plunge that warms overnight is a pond with ambition.

Cold plunges, chilled properly
The contrast circuit

The contrast circuit

Hot, cold, repeat — plumbed as one system with one plant, one controller and one log. The Gorge’s older remedy, engineered: benches where you catch your breath, drainage where you drip, and a path between the two that never ices.

104°F
held to a half-degree, controller-verified, every soak
1,900+
soakers and plungers equipped across the Gorge since 2012
4 min
the median changeover our circuits settle into
9 yr
the oldest pair still running its original chiller

2025 — 2026, the Gorge

Steam and goosebumps, photographed

Six thermal builds from last season, shot at the hours they are actually used — early, and after dark, when the steam and the goosebumps are both honest. The controller screens read the same as the captions.

The Dune Road pair
The Dune Road pair — 104 and 46 sharing one plant, one log
Gorge climb house
Gorge climb house — plunge at 39 training mode, spa at 104
Fennwater courtyard
Fennwater courtyard — contrast circuit under the pergola
The ski-house soak
The ski-house soak — full-foam, sealed lid, minus-20 January, no fight
Marberry plunge
Marberry plunge — ozone and UV, water you could read a watch through
Controller evening
Controller evening — both bodies on one screen, both in spec

Fair questions

Questions for the cold and the hot

The five every Gorge porch reaches once somebody mentions recovery. The studio line answers seven to five, Fennwater time.

Is a cold plunge actually safe?

For healthy adults, in intervals, yes — and we teach the protocol with the plumbing. The controller caps session length, the 39-degree training mode is a deliberate switch rather than an accident of a badly sized chiller, and the plan that comes with every plunge names the intervals our clients actually settle into. Anyone with a heart condition takes the plan to their doctor first, which is advice we print rather than mumble.

What do they cost to run?

Less than their reputation: a sealed, insulated spa at 104 runs a median thirty-one dollars a month on the Gorge tariff, and a plunge holds 46 for about eighteen — the chiller does its work in short sprints once the shell and lid stop losing the argument. The quote carries your figure, modelled on your gallons and your meter, not on a brochure average.

How do you sanitise 104-degree water?

Ozone and UV do the oxidising a hot residual burns itself out trying to do, and the salt-ready generator meters what is left against live readings. The result is water that reads gentle on the eyes and honest on the test — and a log that proves it every hour of every soak, including the ones nobody swims.

Inside, outside, under cover?

All three, with different engineering: outdoor wants the insulation and the lid doing real work, a garden room wants drainage and ventilation drawn at design, and a true indoor pair wants an airside plan before a thermal one. The visit settles it — the Gorge microclimate is why we ask where the water will sit before we say what it will cost.

What maintenance does a pair need?

The weekly check on the plan, a seasonal deep clean that drains the spa side, a filter rotation, and the chiller’s coil washed each spring — about an hour a month of ours, none of yours. The log watches everything between visits, and the one thing it cannot do is keep an unsealed lid honest: that part is on the household.

Word of mouth

The Gorge, before and after

Two bad shoulders and a marathon habit — the contrast pair is the only recovery that has ever felt like it was doing what it claimed. The 46 has not wandered a degree since they set it, the changeover is three steps and a handrail, and the app reads both bodies on one screen my physio now asks to see at appointments.
Coach I. Brandvold · The Contrast Pair, Dune Road
The plunge held 46 straight through a Gorge August, which I did not believe a small tub could do. Then January came and it held it through that too, on eighteen dollars of power for the month. The lid seals like a cooler and the water is cleaner than the stuff we drink — the log says so, hourly, whether anybody looks or not.
T. & M. Osei · Cold plunge, Gorge climb house
The spa is the only room the whole family agrees on, and it stopped smelling like a swimming bath the week Thermal Bay rebuilt it — ozone, they said, and a cover that actually closes. Sunday nights are a rotation now. The seven seats were drawn around our heights and our complaints, and you can tell.
The Ferrell family · The Hot Soak, Fennwater courtyard

Thermal walks along the Gorge road & Fennwater, evenings included · (555) 023-5562 · soak@thermalbay.example

Thermal walks

Come feel both

The visit ends with your hand in a working 104 and a working 46, because the numbers are one thing and the nervous system is another. Plans follow within the week, fixed, with the running figure modelled on your own meter. soak@thermalbay.example

The thermal walk request