The tub is the part people budget for. The running cost is the part that decides whether the thing still gets used in month six.
The ice route
A typical home plunge holds 80–100 gallons. Bringing tap water down to the low 50s takes roughly 20–40 lb of ice, more in summer, and that ice is largely spent after one session because the water warms back up overnight.
At US retail prices, bagged ice runs about $2–$4 for a 10 lb bag. Call it $6–$12 per session. Three sessions a week is roughly $75–$150 a month — plus the trip to buy it, which is the part that actually kills the habit.
The chiller route
A chiller cools the water once and then holds the setpoint, cycling only to defend against ambient warming. Running cost depends on your insulation, your ambient temperature and your setpoint, but a well-insulated tub with a fitted cover typically lands in the region of $15–$40 a month in electricity for daily use.
The break-even against bagged ice generally arrives somewhere between month 8 and month 18, and sooner if you plunge more than three times a week or live somewhere hot.
What actually drives the number
- Insulation and a fitted cover. The single biggest lever. An uncovered tub outdoors in summer can double a chiller's duty cycle.
- Setpoint. Every few degrees colder costs disproportionately more to hold.
- Ambient temperature. A garage in Phoenix and a basement in Vermont are not the same problem.
- Tub volume. More water is more thermal mass — slower to cool, but also slower to warm.
Sizing the chiller
Undersizing is the common mistake: the unit runs constantly, never quite reaches the setpoint, and costs more than a correctly sized one. As a rough guide, a 0.3–0.5HP unit suits a small insulated personal tub, while larger barrels and multi-user setups want 1HP and up. Our 2HP water-cooled chiller is specified for tubs up to 1000 litres and heats as well as cools.
The integrated option
If you would rather not plumb a separate unit, an all-in-one is simpler: our cedar and stainless plunge with a 1.5HP chiller built in runs from a standard outlet with filtration and circulation included, and the Icegalax system pairs an insulated inflatable tub with its chiller in one purchase.
The honest summary
Ice is cheaper to start and more expensive to keep. A chiller is the opposite. If you are testing whether cold exposure is for you, start with ice and an insulated tub. If you already know you will keep doing it, the chiller is the cheaper machine within about a year — and it removes the errand that ends most plunge habits.
See all cold plunges and chillers.
General guidance for setting up home equipment. Not medical advice — talk to a doctor before starting cold or heat exposure, especially with heart, blood pressure or pregnancy considerations.
