SaunaHarbor
Home saunas, sized on the physics
The heat you want is a math problem first.
An undersized stove never reaches löyly. An oversized one cooks the ceiling and cold-soaks your wallet. Size the heater to your actual room before you look at a single product page.
The 60-second sizing
Sauna heater calculator
6.0 kW
For 7.6 m³ with standard insulation. Round up to the next stove size, never down.
82°C at the bench, not the ceiling
The ledger: stoves that hold their heat
Specs verified against manuals · updated Aug 2026
01
The 6 kW workhorse pick
Indoor rooms 5 to 8 m³
6.0 kW · 60 min to 80°C · 90 kg stone capacity
Reaches bench temperature on a standard 240V circuit and holds steam without spiking the ceiling.
02
The barrel-sauna specialist
Outdoor barrels 6 to 10 m³
8.0 kW · outdoor-rated housing · 120 kg stones
Extra capacity covers the heat a curved, weather-exposed shell bleeds that flat rooms do not.
03
The wood-fired classic
Off-grid and purists
14 kW equivalent · no electrical install · CE tested
The longest heat-up of the three, and the one every wood-stove owner defends anyway. There is a reason.
Sized on physics
Every recommendation starts from volume, insulation, and glass area. If the math says 8 kW, no 6 kW stove gets recommended because it is cheaper.
Manuals, not marketing
Specs come from installation manuals and certification sheets, cross-checked between sources. Marketing pages are not a source.
Affiliate-funded, not brand-run
Links may earn a commission at no cost to you. No brand pays for a position in the ledger.