Sauna Heater Size Calculator
Get a starting recommendation for your sauna in seconds. Uses the industry-standard 1 kW per 45 cu ft baseline with adjustments for glass, uninsulated construction, and tall ceilings — the same method Harvia and Huum publish in their sizing charts.
Sizing method used by Harvia, Huum, and independent sauna builders. Recommends from our live in-stock catalog. See full disclaimer below.
Recommended heaters
Matched to your room from our in-stock catalog.
Want a second opinion before you buy? Our sauna specialists can review your build, confirm heater fit, and answer any electrical or install questions.
Talk to a SpecialistRecommendations are a starting point. Confirm the specific heater's own sizing chart, and always work with a licensed electrician for installation and circuit sizing.
Questions on your build? Email info@nwimmersion.com or call the number in our site header.
Sizing guidance only — not a substitute for professional installation. This calculator provides estimates based on published manufacturer cu-ft ratings and standard sauna sizing formulas. Actual heater performance depends on insulation, ventilation, climate, elevation, and installation quality — factors this tool does not measure.
Always confirm final heater selection, electrical requirements (breaker, wiring, GFCI), and installation against the manufacturer's official installation manual, and use a licensed electrician for all 240V wiring. NW Immersion is not responsible for outcomes resulting from installations that do not follow the manufacturer's specifications or applicable electrical codes. Product warranties are governed by each manufacturer's terms.
By using this tool you agree to our Terms of Service.