TL:DR
Skip straight to how to build a chest freezer ice bath or continue reading to learn about the benefits of cold exposure and using a chest freezer cold plunge.
The Benefits of a chest freezer ice bath
“If we always choose comfort, we never learn the true capabilities of our mind or body” - Wim Hof
As humans we desire comfort. Stability. Balance. An equilibrium. Biologically, this desire can be understood as homeostasis and it serves an important purpose - helping to keep our internal environment stable and functioning optimally - allowing us to survive in an ever-changing external environment.
While this might sound good, it’s actually a paradox. By always remaining in balance, by simply surviving, we don’t grow. We don’t thrive. For that we need stress. It’s through stress that we grow and become more resilient, in both body and mind.
It's why I choose cold exposure as a form of positive stress.
Why? Cold exposure provides both physiological and psychological benefits including decreasing inflammation, improving circulation, activating brown fat, boosting focus & attention and helping to combat depression.
Personally, I’ve found cold exposure to be incredible for my mental health as I’m able to unpack and work through problems and can learn to let them trigger me less.
Whenever I’m asked what the best type of cold exposure is, I always answer “it depends”. What’s your reason for doing it? What resources do you have on hand? How much time do you have? Factors like temperature, time and type play a role in providing different benefits of cold exposure (which I discuss in this article).
A barefoot walk, cold shower, taking an extra layer off when it’s cold, an ice bath or a swim at the beach are all great ways to bring cold exposure into your daily life! But - and I know this conflicts with what I wrote at the beginning - sometimes you want consistency and convenience! That’s where a cold plunge comes in.
Having a chest freezer cold plunge at home offers many benefits:
Consistent temperature. Shower and sea temperatures change with the seasons. With a cold plunge it remains consistent all year round.
Adjustable temperature. A cold plunge allows you to slowly decrease the temperature, gradually building up your cold exposure training.
Optimum temperature. 2-3 mins in <4°C water is all that’s really necessary to realise cold exposure benefits. This can be tricky to achieve with an ice bath.
Convenience of an ice bath. They can be used undercover/indoors, are suitable for 1-2 people, but without the need for ice, refilling water or plastic packaging
No travel time. Getting to the beach or a lake for cold exposure is not always convenient or practical. A cold plunge in your garage brings the cold water to you!
Build a daily habit. Having ready access to optimally cold water can help you to build cold exposure training into your daily routine.
Reducing the excuses. Like exercise, we often make excuses for not doing it. A chest freezer ice bath in the next room is one way to remove some excuses…
But, at the end of the day, you still need to get into the water!
Safety Note: Always unplug the freezer before you get in!
How to build a chest freezer cold plunge
Below I’ll walk you through my chest freezer ice bath setup and share the reasons why I chose certain products. Please note, this is what I’ve chosen based on my needs and budget and it’s far from the only way to build a chest freezer cold plunge.
There are plenty of ‘how to’ articles and videos online, but by far the best cold plunge resource is John Richter’s Ultimate Chest Freezer Cold Plunge DIY Guide. It’s 260+ pages covering everything you need to know about setting up and maintaining a cold plunge and I highly recommend it.
I’ve also included some extra resources (and discount offers) at the end of this article.
My chest freezer cold plunge setup:
320L Westinghouse chest freezer
Selleys Knead It Aqua sealant
Inkbird ITC-308 temperature controller
Generic aquarium powerhead pump (1200L/hr flow rate)
Plastic water bottle
Polyester wadding
Assorted plastic tubing and clamps
5kg of Epsom salt
5-6 hours of work
Here's how I built it... (photos at the end)
1. The freezer
Because everyone in Australia decided to become hoarders during the pandemic, it took me 2 months to find a suitable second hand freezer. In hindsight 320L is a fraction too small for me (I’m 186cm), but it’s no less cramped than my portable ice bath, so I make do.
The person I bought it off had it running when I picked it up so I knew it worked and could test the temperature.
Also, it has no castors, so it sits almost flush with the ground, which is good for supporting the water weight (I’m going to buy an EVA gym mat to sit underneath for some extra support).
2. Sealing it
I used Selleys Knead It Aqua (Another of John’s recommendations is JB Waterweld - which is quite expensive here in Australia). It took me 13 tubes to seal everything, including the drainage plug hole. I did apply the putty quite thick, so you might be able to get away with the same amount for a larger freezer. Don’t skimp on this part, no one wants a rusty freezer.
I only used silicone to seal the rim and lid (as these aren’t submerged). Based on John’s advice, I wouldn’t recommend using silicone for the submerged parts.
I lightly sanded the seams, washed the inside with soapy water, let it dry for 24 hours and then began sealing it. It took me less than 5 hours to seal everything. To be on the safe side I let it cure for 2 days before adding the water.
Side note: You can also add a pond liner to the inside for added leak protection and to make cleaning easier, but I’ve held off on this for the time being.
3. Sanitation, filtration & circulation
To keep your water clean and clear these are the three things to think about.
I opted for Epsom salt as my chemical sanitation method (other options include chlorine and hydrogen peroxide). Buying the stuff is quite expensive, with the freight often being as much as the salt itself. To lower the costs, I bought my salt directly from a float tank studio (they use 350kg per tank and I figured if it’s good enough for them, it’ll do the job for me). I started with 4-5kg in 200L of water (which I feel is on the limit of being too much - but we’ll see).
Side note: If you opt for salt, a temperature controller and pump are essential. Salt significantly lowers the freezing point of the water, making it important to monitor the temperature for safety and avoid ice build up, which can create extra strain on the compressor. Also, to avoid rust, make sure you wipe everything down when you get out of the freezer!
For mechanical sanitation, filtration and water circulation I opted for an internal powerhead pump with a DIY polishing filter.
Why? Internal, submersible pumps are preferred to external pumps (the plumbing can be more expensive to buy, complex to set up and can increase the temperature of the water). John’s recommendation is the Marineland Magnum polishing pump/filter. Unfortunately, it’s not available in Australia and if you buy one from the US you need a voltage converter. I looked high and low for a local option but came up short. Regular pond pumps don’t really filter and aquarium filter pumps don’t polish the water, plus I needed something suitable for saltwater. I came across this video on a DIY solution and decided to go with that.
I bought a cheap, generic powerhead pump (to avoid over investing in the early stages), and with a plastic bottle, some tubing and clamps, and some craft store bought 100% polyester wadding, I made a polishing filter pump. The pump is maybe a bit too powerful, but it’s not splashing water everywhere and so far it seems to be doing the job of removing dirt and particulates.
There are more options I could include to keep my water clean and clear, like an ozone generator and UV light, but, I’m keeping it simple for now.
4. Temperature & timer
Before I had a pump or added salt, I just used a digital timer that turned the freezer on for one hour, twice a day. This kept the water at a frosty 0.5-1°C, but without a pump to keep the water flowing, ice started to build up quite quickly. While it’s a cheap and cheerful solution, I wanted better temperature control and the reassurance of clean, sanitised water, so I added salt & pump to the setup.
I keep the pump running all the time (stopping and starting isn’t good for pump life) and have set the temperature controller to 4°C which, now that it’s winter, means the freezer hardly needs to run.
5. Maintenance
As it’s still a fairly new setup, I don’t have much to report. I’ll expand this section over time. So far, the water is cold and clear, which is exactly what I’m looking for ;-)
Resources
John Richter’s Ultimate Chest Freezer Cold Plunge DIY Guide
John’s Chest Freezer Cold Plunge Facebook group
A Practical Guide to Cold Training by Jesse Coomer
YouTube interview with John Richter and Jesse Coomer
Note: I don’t receive commission from these products. I just think they're helpful and wish to support the people behind them.
Important notes:
Once more for good measure; always unplug the freezer before you get in!
The cold is a strong force. It's important to gradually build up the intensity and duration of your cold exposure. Always train without force and listen to your body carefully. If not practiced responsibly, you risk hypothermia. Individuals should not practice cold exposure if pregnant or breastfeeding, after drinking alcohol, immediately after meals or during strenuous exercise. Those with serious medical issues (including Raynaud's or cold urticaria) should consult a medical practitioner before practicing.
Interested to experience your first ice bath or want to learn how to go deeper? Join me at one of my upcoming workshops
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