What a cold plunge costs to run in the UK

The running cost of a cold plunge is almost entirely the chiller. Here is how to estimate it for your setup, and what makes the biggest difference. The running cost calculator does the arithmetic with your own tariff.

The maths

A typical 1/3 HP to 1/2 HP home chiller draws 300 to 600 watts while running. How many hours a day it runs depends on tub insulation, whether a cover is used, ambient temperature and target temperature. Multiply watts by hours by your unit rate.

Assumes a 450 W average draw and a unit rate around 25p per kWh. Your tariff will differ.

What moves the number

• A cover. The single cheapest improvement. An insulated lid can halve run time.
• Insulation. All-in-ones and insulated tubs cost more up front and less every month.
• Location. A garage or north-facing wall beats a sunny patio.
• Target temperature. 8C costs noticeably less than 3C in summer.
• Water changes. Good filtration means changing 300-500 litres every 4-8 weeks rather than weekly. Water is cheap; the time is not.

Other costs

Filter cartridges (£10 to £30 every 1-3 months), sanitiser or minerals (a few pounds a month), and water. Budget £5 to £15 a month on top of electricity.

How much electricity does a cold plunge chiller use?

A typical 1/3 HP to 1/2 HP home chiller draws 300 to 600 watts while running. Over a month that is roughly £10 to £25 for an insulated, covered tub held at 5C, and several times that for an uninsulated tub outdoors in summer.

Does a cover make a difference?

Yes, more than anything else. An insulated lid can halve chiller run time because most heat enters through the open water surface.