What a cold plunge costs to run: ice vs chiller, with the arithmetic

Cold plunge marketing talks about temperature. Cold plunge ownership is about two costs nobody puts on the product page: what you spend chilling the water, and what you spend changing it.

The ice-versus-chiller break-even

This is the calculation that should happen before any product comparison.

Ice. Cooling roughly 100 gallons from tap temperature to the mid-40s takes on the order of 40–60 lb of ice, depending on your starting temperature and how well the tub holds. At typical US bagged-ice prices that is $8–15 per session.

Sessions per week	Annual ice cost
1	$416 – $780
2	$832 – $1,560
3	$1,248 – $2,340
5	$2,080 – $3,900

Chiller. A one-time $1,000–$3,000, plus a $250–$600 dedicated circuit, plus modest ongoing power.

The non-financial part matters too. Ice means a trip to the store before every session, which is the friction that quietly ends most ice-based plunge habits by month four. Chillers convert a chore into a thermostat setting, and habit adherence is arguably what you are really buying.

Where the electricity actually goes

A chiller does two jobs with very different costs.

Initial pull-down — 65–70°F tap water down to 45°F — runs the compressor hard for 8 to 24 hours depending on horsepower and gallons. This is the expensive part, and it happens once (plus after every water change).

Hold mode replaces heat leaking in. On a well-insulated tub with a sealed lid, the compressor cycles briefly and infrequently. On a thin tub with a loose lid, it runs and runs.

The variable that dominates hold cost is not horsepower. It is evaporative and conductive loss, which means:

1. Lid seal. The single biggest heat gain path in an uncovered tub is evaporation from the surface. A rigid, sealing insulated lid can roughly halve hold-mode energy.
2. Wall insulation. A double-walled insulated tub versus a single-wall polymer shell is a large multiplier on standby load.
3. Ambient temperature. A 95°F garage means a 50°F differential to fight. A 60°F basement means 15°F. That is more than three times the load for identical equipment.

Water changes: the real maintenance cost

Setup	Realistic change interval	Annual water changes
No filtration	~weekly	~52
Filter only	2–3 weeks	~20
Filter + ozone	Months	~4–6

Each change means draining 100–130 gallons somewhere sensible, refilling, and — if chilled — paying for another full pull-down. That last point is the hidden cost of poor filtration: every water change costs you a pull-down cycle, not just the water.

This is why ozone is worth more than its spec-sheet prominence suggests. It is not a health feature; it is the difference between fifty-two drain-and-refills a year and five.

Drainage

You will be dumping 100–130 gallons on a schedule. Onto a lawn occasionally is fine. Onto the same three square feet of lawn every week is not — it will die, and then it will be mud.

Budget $200–$600 for a French drain to a dry well, or plan a hose route to a storm drain or a gravel bed. Indoors on a garage slab, plan the route to a floor drain or door before you position the tub, because a full plunge is not something you reposition afterwards.

Total cost of ownership, three years

Rough scenarios for a three-times-weekly habit, equipment plus running:

Ice route: $2,999 tub + roughly $3,700–$7,000 of ice = $6,700–$10,000

Mid chilled route: $4,499 all-in-one + $450 circuit + power and maintenance = roughly $5,300–$6,000

Premium chilled route: $8,490 integrated + $450 circuit + power and maintenance = roughly $9,300–$10,000

At three sessions weekly, the mid chilled route is the cheapest way to own this over three years — cheaper than ice, and roughly $4,000 less than the premium integrated option.

Full product rankings: the best cold plunge tubs of 2026.