Heaters & Components

Sauna Stones

Sauna stones are not interchangeable. The mineral composition of the stone affects how it absorbs and releases heat, how it handles repeated thermal cycling, and how long it lasts before needing replacement. My Harvia KIP is loaded with olivine (dunite) stones — the standard recommendation from Harvia and most Finnish sauna manufacturers. Olivine handles thermal shock well and produces clean steam. Peridotite is a close alternative with similar properties. Volcanic basalt is often sold as a sauna stone but fractures faster under repeated heating and cooling. The stones you want to avoid are anything porous or with high iron content, which can crack and produce unpleasant smells. Replacement interval depends on use frequency — most sources recommend inspecting stones annually and replacing cracked or crumbling ones, with a full replacement every 3–5 years for regular users. Stone weight matters too: your heater specifies a minimum and maximum load, and under-loading results in poor löyly quality. The guides here cover sauna stone selection, maintenance, and replacement by heater type and use pattern.