5 things to look out for when buying a cold plunge for the first time

Hey cold plungers! We’re HYDRAGUN – a fitness/wellness tech company made up of a team of peak performance fanatics from around the world.

We make recovery products trusted by Olympians, World Champions, NFL players, and other pro athletes and health and fitness professionals – including an ultra-quiet massage gun, a best-selling no-BS sauna blanket, and a heated knee massager beloved by runners and endurance athletes on four continents.

Our latest release is the Supertub – which we designed to be the best-spec'd and best-value cold plunge on the market in 2024.

We equipped it with everything you need in a cold plunge – including these five things you should look out for when you’re buying one for the first time.

1. Chiller horsepower

This is the primary spec to look out for.

It dictates how much cooling power your cold plunge has, so that it can get the water down to the freezing cold temperatures you want, and keep it there.

We recommend a 0.6 horsepower chiller if you live in a temperate area, and 0.8 horsepower in warmer climates.

If horsepower is too low, your chiller will struggle to keep the water cold, leaving you with warmed-up water and/or increasing the possibility of a breakdown.

If horsepower is too high, you’re paying a lot extra for not much added benefit.

Contrary to popular belief, higher horsepower doesn’t make the water colder once you’re past a certain point. In fact, most high-quality true-to-spec cold plunges 0.6hp and higher can comfortably go down to 37-39°F (3-4°C) regardless of horsepower.

Chillers 1-2hp and higher are best suited for commercial use cases (e.g. if you’re running a high-traffic gym or spa). But companies have started offering them to regular customers as well, because they command higher prices of around US$5,000 and up.

The Supertub chills water all the way down to (37°F) 3°C for a market-beating $2,999 for our 0.6hp model, and $3,999 for our 0.8hp model.

We tested the water with a thermal camera and the lowest temperature reflected from the tub water was 1.2°C

Its powerful, compact Permafrost™ chiller has up to 26-42% less bulk and a smaller footprint that’s easier for residential users to maintain, while still being powerful enough that it can stand up to fairly high-traffic situations, like a plunge party or sporting event with 10-12+ plungers an hour. It also features an automatic power-saving mode that ensures it’s never drawing more power than it needs, and IPX4 water resistance for your peace of mind.

2. Tub type

Next we’ll look at the tub itself.

There are three main materials on the market, and you can find the pros and cons of each below:

As you can see, we found that inflatable tubs provide the best balance of performance, convenience and ease of handling, and durability overall.

Performance. Steel tubs face multiple performance issues, so we recommend avoiding them if possible. They’re poorly insulated, so water in the tub will heat up faster when it gets warm, reducing the energy efficiency of your cold plunge. They also attract much more condensation than other materials, forming large drips and puddles outside and around the tub and encouraging mold, mildew, and water damage in the surrounding area.

Ease of handling. During the lifetime of your cold plunge, you’ll need to change out the water, clean the tub, mop up spills and splashes, check the area around and underneath the tub for mold and mildew, and so on. We found during our long-term product testing process that a lightweight inflatable made maintenance a lot easier than a bulky hard-sided tub.

Durability. Inflatables can be just as durable as hard-sided tubs if construction and materials are done right. For instance, we make the Supertub out of military-grade, double-walled marine vinyl – the same material military life rafts are made of. It’s tough, won’t degrade in the presence of minerals and salts, and will stand up to the elements and water.

The main downside of an inflatable tub is of course that you’ll need to inflate it before use. This can be a hassle if you’re using a manual hand pump. So we include an electric air pump (worth $149) for free with every Supertub, so you can inflate it to the correct pressure of 10 PSI at the push of a button, and in just 4-5 minutes.

A final point to note is tub size. If you intend to make cold plunging a habit, we recommend a full-sized tub you can use comfortably. A high-sided compact tub may feel cramped and will be harder to climb into and out of safely and comfortably, especially when you’re wet.

3. Filtration and sanitation

3.1 Three layers of filtration and sanitation

Most cold plunges come with one or more of the following filtration sanitation devices: a water strainer, a water filter, and an ozone generator. The Supertub uses all three to make sure you’ll have sparkling clean water all day, every day.

The water strainer is a metal mesh strainer that keeps the water clear of physical debris like hair, sediment, and dirt.

The water filter removes smaller particles like dust, body oils and sweat. Most high-quality cold plunges, including the Supertub, use filters with a filtration grade of 20 microns, for the best balance of cleanliness and filter lifespan.

Finally, the ozone generator handles pathogens and other contaminants on microscopic level, destroying and preventing the proliferation of microbes including viruses, bacteria like E. coli and staph, fungi like Candida albicans (which causes yeast infections), and parasites like Cryptosporidium parvum (a protozoan parasite which infects the intestinal tract and is a leading cause of waterborne disease in the US).

There are two key things to note when you’re looking at the sanitation system of a cold plunge.

First, some brands (including some which are bigger or more premium-priced) try to save on component costs by replacing the ozone generator with a UV sanitization system instead. We strongly suggest avoiding models that use UV, as ozone provides significantly superior sanitation, water clarity and texture, and odor management in comparison.

In particular,

Ozone destroys biofilm (the slimy film caused by bacteria and microbe buildup), while UV does not;
Ozone destroys humic and fulvic acids (byproducts of plant and animal matter decay), while UV does not;
Ozone destroys microbes including Cryptosporidium parvum, while UV only deactivates them;
Ozone is a micro-flocculent, meaning it eliminates water cloudiness, but UV is not;
If your water does get a little cloudy over time, ozone will continue to function, but UV’s efficacy will be impacted (as the cloudiness will absorb the UV light);
Ozone from the generator will diffuse throughout the water in the cold plunge system, while UV only affects the water that is passing through the UV chamber;
Ozone generator cells do not require replacement, but UV vapor lamps may need to be replaced as soon as every 3-12 months, and disposal must be done carefully as lamp gases are considered hazardous waste.

Second, check if the water strainer is internally or externally positioned. Internal strainers are positioned behind a panel within the chiller, are often difficult to reach, and require tools such as a screwdriver to access. External strainers are easy to access with no tools required.

We recommend an external strainer setup to reduce hassle whenever you find yourself needing to rinse out the strainer (which may be roughly once every couple of weeks).

3.2 Water balancing supplies

While we’re on the topic of sanitation, you may also be curious about the role of water balancing supplies in maintaining your cold plunge.

This includes items like sanitizer, oxidizer, and pH balancers.

There’s some controversy in the cold plunge community about whether or not these are necessary, and how much to use.

That’s because water quality and plunging habits vary widely among users.

So we recommend that our customers experiment to find a water balancing protocol that works best for them.

The general guideline on this is as follows:

Sanitizer and oxidizer use is a tradeoff. The more sanitizer and oxidizer you add (within reasonable limits), the cleaner your water becomes, but the more frequently you’ll need to change your water filters. This is because sanitizer and oxidizer clean your water via chemical reactions, producing byproducts that need to be filtered out.

You may want to use more sanitizer and oxidizer if you plunge very often, if you’re hosting a plunge party with a group of friends, or if you want to change the water in your tub less frequently. You may decide to use less if there are only one or two people using your plunge, and you don’t mind refreshing your water at a more regular interval (usually around once a month).

pH balancers. You’ll also want to make sure your water’s pH isn’t too high or too low. Water that’s too acidic can end up corroding metal components, while an overly high pH can lead to problems like calcium buildup. Those with skin sensitivity may also experience reactions if the pH is too unbalanced in either direction.

A quick pH test using a test strip (once every few weeks) should be enough to help you confirm your water is more or less within the right pH range. If it’s not, use pH Up or pH Down accordingly to adjust.

We include a starter kit of basic water balancing supplies (including sanitizer, oxidizer, pH Up, pH Down, and test strips) for free with every Supertub, so you can be sure you have everything you might need to maintain your water.

4. After-sales service

Like a swimming pool, hot tub, or air conditioning system, cold plunges require some maintenance, and you may find yourself needing small repairs or fixes over the years.

There may also be a bit of a learning curve as you learn to set up and use the product.

We’ve tried to make Supertub setup as simple as possible, including with our comprehensive step-by-step video walkthrough. For most of our customers, it takes as little as 15-20 minutes to complete.

But some users do run into situations where they need additional assistance. Even small oversights can sometimes have a significant impact on the performance of your plunge.

One of our customers had her chiller start making mysterious noises and showing unexpected errors just days after setting up her Supertub. Our support team traced the issue back to the fact that she’d simply failed to screw in the water filter tightly enough, which was letting air bubbles into the system.

Another customer’s water composition caused the formation of a red film on his water filters, and unusually short water filter lifespans. Our team worked with him to find the right balance of sanitizer, oxidizer, and pH balancers for his setup

At HYDRAGUN, we are cold plunge enthusiasts ourselves – in fact, both our CEO and the Supertub’s Product Manager use the Supertub every single day.

So we know that cold plunges can be a joy and a breeze to own and use – but only if you set them up right.

Angela Lee Pucci (ONE Women's Atomweight Champion) and Bruno Pucci (x IBJJF NoGi World Champion) enjoying their Supertub

That’s why you should make sure to buy from a brand that provides robust customer support options.

For us, that starts from the moment you place an order. All our stock ships from our facility in Edison, NJ, so we can fulfill orders immediately with no lead time. If you place an order today, your Supertub will reach you in just 3-5 business days – as compared to the industry standard of up to 4-8 weeks of lead time while your plunge is manufactured or shipped in from overseas.

Then, if you run into any issues during the setup process, we’ll set you up on a live video call with a dedicated member of our team so we can troubleshoot any issues you may run into – no waiting for days for back-and-forth via email (unless that’s your preferred communication option). And if we can’t resolve your issue right away, we’ll provide a white-glove door-to-door repair or replacement service for any parts that need a fix or a tune-up.

These days, with the cold plunge trend on the rise, we see many new online brands selling plunges for thousands of dollars without saying a word about warranty or maintenance, and with no customer support systems beyond an email address, if that.

We’ve also seen even fairly prominent cold plunge brands disappear without a trace, leaving their customers in the lurch. You may have seen or heard of a brand called PolarPod, which advertised heavily on social media and had thousands of followers – only to seemingly disappear overnight.

This is not how we think business should be done. We believe that when you take the plunge with the Supertub, you’re making a long-term investment that should serve you well for many years to come.

To that end, the Supertub comes with two years of free warranty– twice as much as what most major brands offer. And we’ll continue to provide service and support (including spare parts at cost and maintenance and repair advice) even after your warranty period is over.

We also have a free 30-day “love it or return it” offer. This is in contrast to most other major brands – which only allow returns if you haven’t opened the product, charge hundreds in restocking or return shipping fees, or simply don’t offer returns at all.

5. Hidden costs

One trend we’ve noticed in the cold plunge world is lowering sticker prices up front, but unexpectedly piling on shipping fees, taxes, and other add-on costs at checkout

At HYDRAGUN, we prefer to keep things transparent. We charge $400 in flat-rate shipping fees within the US ($500 for Alaska or Hawaii) – and that’s it.

We also prefer to avoid plying you with expensive upsells and add-ons – like a tub cover for over $300, an electric air pump for $150, or an anti-slip mat for $100.

Instead, the Supertub comes with everything you need to start plunging right away, namely:

An electric air pump for fast and easy setup;
A water filter; and
A complete water balancing kit.

As a bonus, we’ve also included a selection of the most useful accessories:

An anti-slip mat to help you get in and out of the tub safely, absorb excess water, and keep the area around your tub clean and dry;
A skimmer net for fishing out debris (like fallen leaves); and
A phone mount so you can document and share your cold plunge progress on your smartphone.

All in, that comes to about $500 in value thrown in for free.

How the top brands compare

We designed the Supertub to be the best cold plunge offer on the market today.

We gave it excellent specs, a sleek and simple design, and all the features and accessories you’ll need for the complete cold plunge experience– all at an ultra-competitive price.

Some highlights of our offer:

Just $2,999 for our 0.6hp model and $3,999 for our 0.8hp model
Comes with everything you need, including a free Water Balancing Kit and useful accessories worth $500
No lead time – get it in 3-5 working days vs. the industry standard of 4-8 weeks
Free 2-year warranty – double what our competitors are offering
Try it risk-free with free 40-day returns

If you want the full details, check out the table below. It summarizes all the key things to look out for when choosing a cold plunge, and shows how the Supertub compares to other top cold plunge brands in the US.