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Cold plunge

Cold plunge or ice bath: which is right for you? (UK guide)

Ice in a tub or a chilled plunge? What ice costs per session, what a chiller costs to run, water care, space, noise and weight, and a table to help you choose.

By Birch & Berg. Last checked .

Short answer: an ice bath is cheap to start. You fill a tub or bath with cold water and add ice. But every session needs fresh ice: roughly 30–35 kg for a 300-litre tub, which costs about £13–£31 in supermarket bags. A chilled plunge costs more to buy, but its electricity typically comes to about £25–£50 a month, and the water is ready when you are. If you plunge once a week or more, a chiller usually costs less to run. For the odd session, ice is simpler.

People use "cold plunge" and "ice bath" for the same thing. In this guide, an ice bath is a tub or bath cooled with ice. A cold plunge is an insulated tub with a chiller that holds a set temperature.

1. How much ice you need

Ice cools the water as it melts. Our estimate:

Ice needed = about 10–12 kg for every 100 litres of water

That assumes tap water at 12°C, a target of 3°C and ice from a freezer, with no heat getting in. It matches our running-cost guide: about 30–35 kg for a 300-litre tub. The colder the ice, the less you need.

In practice you need more:

  • in late summer, when tap water is warmer;
  • on a warm day, or in a tub with no insulation or lid;
  • once you get in, because your body warms the water.

Leave room for the meltwater. 30 kg of ice becomes about 30 litres of water.

2. What the ice costs per session

We checked UK supermarket prices on 29 September 2026. A 2 kg bag of ice cost from 85p (own brand) to £1.70.

Water in the tubIce needed (our estimate)2 kg bagsCost per session
100 litres10–12 kg5–6£4.25–£10.20
200 litres20–23 kg10–12£8.50–£20.40
300 litres30–35 kg15–18£12.75–£30.60

The low figure is the fewest bags at 85p. The high figure is the most bags at £1.70.

The water warms again within hours. Unless the weather keeps it cold, you need about the same amount of ice each time. Making your own saves buying bags, but 30 kg of ice needs a lot of freezer space.

3. What a chiller costs to run

We use the same figures as our running-cost and chiller guides. As an illustration, a chiller drawing 0.8 kW that runs 4–8 hours a day uses 3.2–6.4 kWh. At the Ofgem price cap for 1 October to 31 December 2026 (26.32p per kWh, paying by direct debit):

UseEnergy per dayCost per dayCost per 30 days
Lower (mild weather, lid on, insulated tub)3.2 kWh£0.84£25.27
Higher (warm weather, colder target, lid often off)6.4 kWh£1.68£50.53

A chiller that's left running costs about the same whether you plunge once a month or every day. These figures leave out the daily standing charge, which you pay anyway. The chiller's power rating is on the product page.

4. Ice or chiller: a cost illustration

For a 300-litre tub, using the figures above. The chiller runs all month; the ice is bought fresh for each session.

Sessions in 30 daysIceChiller electricity
1 (about once a month)£12.75–£30.60£25.27–£50.53
4 (about once a week)£51.00–£122.40£25.27–£50.53
12 (about three a week)£153.00–£367.20£25.27–£50.53

This leaves out what each costs to buy. A chilled plunge costs more up front. An ice bath can use a tub or bath you already have. Compare the price of a chiller with what you'd spend on ice in a year, at the rate you expect to plunge.

5. Water care

  • Ice in a household bath: drain it after each session. There's no water to look after.
  • Ice in a tub without a filter: the water isn't filtered or sanitised, so change it often and clean the tub between fills.
  • A chilled plunge: the chiller circulates the water, and most chillers filter it too. Follow the maker's routine for the filter and sanitiser. HSE's spa-pool guidance treats UV and ozone as extras alongside a sanitiser, not a replacement. Our chiller guide has the detail.

Whichever you choose, rinse off before you get in and keep the lid on between sessions. When you empty a tub, don't let water containing sanitiser run into a pond, stream or wildlife area.

6. Space, noise and weight

Space

  • A chiller sits beside the tub and needs the airflow gap the maker specifies. It also needs a weatherproof, RCD-protected socket close by, without an extension lead. Our electrics guide explains.
  • Ice needs freezer space, or a trip to the shop before each session. For 300 litres, that's 15–18 bags to carry.

Noise

  • A chiller hums from its compressor and fan. Check the dB(A) figure, and keep it away from bedroom windows, yours and your neighbours'. In England, councils can act on noise that unreasonably and substantially interferes with the use or enjoyment of a home.
  • Ice makes no noise.

Weight

  • Water weighs about 1 kg per litre. A 300-litre tub holds about 300 kg of water, before the tub and the people in it. Ice adds its own weight: 35 kg of ice is 35 kg more.
  • Stand a tub on a firm, level base. Check the load limit before putting a filled tub on decking, a balcony or an upper floor. Our base guide shows the weight maths.
  • In a household bath, keep to the normal fill level and leave room for the ice.

7. Convenience

  • Chiller: it holds the temperature you set, day and night. Lift the lid and get in.
  • Ice: buy or make it, carry it, tip it in and stir it through. The water starts warming once the ice has melted, so each session is a little different.

8. Which suits you?

Your situationBetter fitWhy
You want to try cold water before you commitIce bathNothing to buy or install
You plunge once a month or lessIce bathYou only pay for ice when you use it
You plunge once a week or moreCold plungeIce soon costs more than the chiller's electricity (section 4)
You want the same temperature every timeCold plungeThe chiller holds a set temperature
You want to plunge in summerCold plungeWarmer tap water means more ice
You have no outdoor socket or suitable baseIce bathA household bath needs neither
You don't want to carry iceCold plunge300 litres needs 15–18 bags a session
Your neighbours are close byEither, with careIce is silent; site a chiller away from windows

Using cold water safely

  • Cold water can cause cold water shock: an involuntary gasp, and a sudden rise in heart rate and blood pressure. The RYA says the risk applies in water below 15°C. Get in slowly, keep early sessions short, and don't plunge alone.
  • Get out if you feel numb, confused or unwell.
  • If you're pregnant, or have a heart condition, high blood pressure, Raynaud's or any other medical condition, ask your GP first.
  • Use ordinary ice only. Never use dry ice (solid carbon dioxide). It's about minus 78°C, it can cause cold burns, and it gives off carbon dioxide gas.
  • Stir the ice through before you get in, so the water is an even temperature.
  • Always supervise children. Secure the lid when a tub isn't in use, and drain a household bath after each session.
  • Keep plugs, cables and electrical items away from the water.

General guidance, not medical advice.

FAQs

How much ice do I need for an ice bath?
By our estimate, about 10–12 kg for every 100 litres, to take 12°C tap water down to 3°C. You need more in warm weather.

Is an ice bath cheaper than a cold plunge?
To start, yes. To run, it depends how often you use it. In our illustration, ice for one session a week in a 300-litre tub costs about £51–£122 a month, against about £25–£50 of electricity for a chiller.

Can I use the bath at home?
Yes. Keep to the normal fill level, follow the safety points above and drain it afterwards.

Can I add ice to a chilled plunge?
Check the maker's instructions first. The chiller is there to do the cooling, so you shouldn't need to.

Figures are estimates for guidance. Ice prices are UK supermarket prices we checked on 29 September 2026. Running costs use the Ofgem price cap average for England, Scotland and Wales. Your costs depend on your tub, tariff, weather and how you use it.

Sources

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