Plan a sauna or cold plunge with real numbers
Engineering calculators, a cross-brand spec database, and the electrical math no retailer spells out, so you buy the right heater, chiller and circuit the first time.
New to this? Pick your project
Room size → heater → circuit → build → first heat, in order, with a shopping list.Build a cold plunge
Tub → chiller → plumbing → power → clean water, with a parts list and running cost.
Calculators
What kW your room needs.Electrical circuit
Breaker, wire & voltage drop.Chiller size
BTU/hr and HP for your plunge.Running cost
Monthly $ at your rate.Room planner
Bench, door & ventilation.
Cross-brand specs
kW, control, room size, circuit, every brand.29 cold plunge chillers
HP, BTU/hr, ozone & filtration.23 cold plunge tubs
Volume, material, insulation.
Why this exists
Most sauna calculators live on a retailer’s site and quietly recommend what that retailer sells. We do it differently: the formulas are published, the specs come from manufacturer manuals, and the heater we suggest is the one that fits your calculated load, not the one with the best margin. The circuit math (breaker, wire gauge, voltage drop by run length) is the part nobody else finishes, and it’s the part that fails an inspection.
Harvia vs HUUM vs Finlandia vs Vevor, spec for spec.Guides
Vapor barrier, ventilation, cost of ownership, and more.Wood species
Cedar, hemlock, spruce, thermo, heat, resin, price.Methodology
Every formula and assumption, in the open.
This is a reference estimate, not an electrical design. Circuit sizing, GFCI/GFPE requirements, and conductor selection must be verified and installed by a licensed electrician to your local code (NEC and any local amendments take precedence).