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Cold Plunge Chiller for Bathtub: Best Options and How to Install

You do not need to buy a separate cold plunge tub to get a chiller-cooled cold plunge. Your existing bathtub works. This guide covers four options from the purpose-built HomePlunge H3 (no plumbing required, $2,599) to a DIY chiller build ($750-900), plus what you need to know about bathtub-specific limitations.

CPS
Written and edited by
The ColdPlungeSpot Editorial Team
We read the published cold water immersion research and the manufacturer specifications, then write up what they actually support. We do not perform first-hand product testing, and we say so on every page that reports a number.
May 17, 2026  ·  10 min read
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Quick Answer

Best turnkey: HomePlunge H3 ($2,599) - reaches 34°F in 90 minutes, no new plumbing. Budget: Pod Company Universal Chiller ($599) - plug-and-play, 41°F. DIY: Active Aqua 1/4 HP + overflow drain fitting (~$750) - reaches 34-40°F, 4-8 hour initial cooldown.

Two approaches: purpose-built vs DIY

The main decision is whether to buy a purpose-built bathtub cold plunge unit (HomePlunge, Pod Company) or build a DIY system using an aquarium chiller and overflow drain fittings. The performance ceiling is the same. The differences are speed of initial cooldown, ease of installation, and cost.

Purpose-built
Price: $599-$2,599
Installation: minimal to none
Cooldown: 90 minutes (H3) to 6-10 hours (Pod Company)
Best for: convenience, no DIY, faster setup
DIY
Price: $750-900
Installation: basic plumbing (overflow drain)
Cooldown: 4-8 hours initial; maintain overnight
Best for: cost savings, same final temperature

Our options

Best pickTurnkey
$2,599

HomePlunge H3

34°F min  ·  ~90 min cooldown  ·  No plumbing - suction cup attachment

The HomePlunge H3 is the best purpose-built bathtub cold plunge unit available. Its CES award recognition confirms genuine innovation in the category. For users who want a no-plumbing, high-performance option for their existing bathtub without a DIY build, this is the correct choice. The $2,599 price is justified by the speed (34°F in 90 minutes), the quality of the filtration system, and the fact that no installation expertise is required.

Pros
CES Innovation Award winner 2025 + TIME Best Inventions 2025
Reaches 34°F in ~90 minutes - faster than most DIY setups
No new plumbing - attaches to existing bathtub via overflow drain
Includes filtration and ozone sanitation
4.98 star average rating at time of writing
Cons
Higher cost than DIY equivalent ($2,599 vs ~$750-900 DIY)
Requires your bathtub to remain full between sessions (or refill each time)
Suction cup attachment limits compatible tub styles
Check price →
Turnkey - Compact
$1,999

HomePlunge Bella

36-38°F min  ·  ~110 min cooldown  ·  No plumbing - compact form factor

The Bella is the right choice if the H3 price is prohibitive or your bathroom space is limited. Performance is 90% of the H3 at roughly 75% of the price. If you have a small bathroom or are targeting sub-40°F rather than sub-35°F, the Bella is the better value.

Pros
Lower price than H3 ($600 less)
Compact design for smaller bathrooms and tighter spaces
1/2 HP chiller - sufficient for standard bathtub volumes
Same no-plumbing attachment system as H3
Cons
Slightly higher minimum temperature than H3
Longer cooldown time than H3 (~110 vs ~90 minutes)
Compact size means some bathtub configurations are not compatible
Check price →
DIY Build
~$750-900

DIY Active Aqua 1/4 HP + Bathtub Adapter

34-40°F min  ·  4-8 hrs initial cooldown  ·  Basic plumbing (overflow drain fitting)

The DIY approach costs $750-900 versus $2,599 for the HomePlunge H3. The primary trade-offs are cooldown speed (4-8 hours vs 90 minutes) and installation effort. If you are comfortable with basic plumbing and do not mind pre-chilling overnight, the DIY build achieves the same final temperature for 65% less. The key advantage of the HomePlunge is convenience and speed - not superior refrigeration technology.

Pros
Most affordable path to a chiller-cooled bathtub cold plunge
Same chiller hardware as major brands at OEM cost
Titanium evaporator handles skin oils and minerals
Achieves same final temperature as HomePlunge H3 (34-40°F)
Cons
Initial cooldown 4-8 hours (vs 90 min for HomePlunge)
Requires basic plumbing work (overflow drain fitting installation)
No integrated filtration - need separate filter housing
Less polished appearance than purpose-built units
Check price →
Universal Chiller
$599

Pod Company Standard + Bathtub

41°F min  ·  6-10 hrs initial cooldown  ·  Universal fitting - connects to any tub

The Pod Company Standard at $599 is the most affordable turnkey option for bathtub cold plunge use. The 41°F floor is adequate for most cold plunge protocols (most research uses 50-59°F; the 41°F floor covers the common 45-55°F range comfortably). The 39-45 dB noise level is genuinely suitable for indoor bathroom use. Good option if you want something ready to plug in without any installation.

Pros
Plug-and-play with integrated pump and 20-micron filter
Universal fitting explicitly marketed for bathtub compatibility
39-45 dB - quiet enough for indoor bathroom use
Pod Company explicitly states bathtub compatibility
Cons
41°F minimum - not for protocols requiring sub-40°F
Long initial cooldown (uninsulated bathtub loses heat quickly)
Running cost higher than insulated tub setup (more continuous cycling)
Check price →

Bathtub limitations you should know about

No insulation
Ceramic and porcelain bathtubs lose heat faster than a purpose-built insulated tub. Your chiller will run more frequently in maintenance mode, costing more in electricity and wear. Insulating a bathtub externally (foam panels, insulated blanket) can improve this significantly.
Shared household use
A bathtub dedicated to cold plunge use makes more sense for single-person households or dedicated bathrooms. Shared bathrooms create friction: the tub needs to be emptied/refilled frequently, or kept cold and covered between sessions.
Drain rate
Most bathtub drains flow at 3-6 gallons per minute. If your chiller setup requires draining between sessions, that is 8-20 minutes for a 60-gallon tub. Factor this into your workflow.
Overflow fitting compatibility
DIY builds require replacing the overflow drain plate with a dual-port fitting. Most standard American bathtubs have 1.5" or 2" overflow drain openings. Some clawfoot, jacuzzi, or custom bathtubs have non-standard fittings - verify your overflow drain size before buying hardware.

Frequently asked questions

Can you use a cold plunge chiller with a regular bathtub?+
Yes. Purpose-built: HomePlunge H3 ($2,599) or Bella ($1,999) - no new plumbing, attaches via overflow drain. DIY: Active Aqua chiller + mag-drive pump + overflow drain fitting for $750-900. Pod Company Universal Chiller ($599) also works with explicit bathtub compatibility. Standard bathtubs hold 40-80 gallons - within range of 1/4-1/3 HP chillers.
What is the HomePlunge and does it work?+
The HomePlunge H3 ($2,599) connects to your existing bathtub via suction cups and an overflow drain fitting - no new plumbing. CES Innovation Award and TIME Best Inventions 2025 winner. Cools to 34°F in ~90 minutes. 4.98 star average rating. The Bella ($1,999) is the compact version for smaller bathrooms.
How much water does a bathtub hold for cold plunge?+
A standard American bathtub holds 40-80 gallons. For cold plunge use (water covering shoulders when seated), typically 40-60 gallons. This volume is ideal for 1/4-1/3 HP chillers.
What are the disadvantages of a bathtub cold plunge?+
Bathtubs are uninsulated - ceramic and porcelain lose heat quickly, requiring more continuous chiller operation. Bathtubs cannot be dedicated exclusively to cold plunge if shared by a household. A purpose-built insulated tub is the better long-term solution; a bathtub chiller is the right entry point when you want to start without a separate tub purchase.
How do I connect a chiller to my bathtub without a plumber?+
The HomePlunge connects without new plumbing using an overflow drain adapter and suction cups. For a DIY approach, the bathtub overflow plate (the round cover on the tub wall below the faucet) can be replaced with a dual-port overflow fitting: one port for water out to the pump/chiller, one port for return. Most bathtub overflows use a standard 1.5" or 2" diameter - fit a barbed fitting for your chiller hose. The job takes 30-60 minutes with basic tools.

Sources

What this page relies on. Specifications and prices from manufacturer pages change often, so check the brand before you buy.

  1. HomePlunge. HomePlunge H3 bathtub chiller: product page. thehomeplunge.com.
  2. Active Aqua (Hydrofarm). Active Aqua water chiller, 1/4 HP: listing and specifications. amazon.com.
  3. Eaton. GFCI 210.8(F): outdoor outlets under the 2023 NEC. eaton.com.

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