Start with the System Designer if you have a tub or target temperature. Use the guides when you are still choosing the vessel, chiller or plumbing strategy.
Choose what you are trying to solve
Why ChillSizer is system-first
A high-volume pump can still deliver too little water after a restrictive filter. A large-looking chiller can still miss a cold target in a hot uninsulated tub. ChillSizer solves thermal and hydraulic requirements together, then shows confidence and the uncertainty that matters.
Learn before you buy
Use the Knowledge Base for DIY building, insulation, filter care, troubleshooting, commissioning and operating cost. Use the Methodology to see equations, data quality and limitations.
Frequently asked questions
What do I need for a cold plunge system?
A suitable tub, cooling method/chiller, pump, filtration, plumbing, cover/insulation and safe electrical installation for powered systems.
Should I buy the tub or chiller first?
Usually define the tub first because its usable volume and insulation determine much of the cooling load.
Can ChillSizer tell me exactly how long cooling takes?
It provides a range and confidence level because insulation, solar exposure and low-temperature chiller performance are not perfectly known in every installation.
Sources & data references
What to read next
Run your exact setup
Use your real tub volume, temperature target, climate, pump, filter and plumbing. ChillSizer checks thermal capacity and actual modeled flow together.
Open the System Designer