For a sauna stove to last for decades, not just a few seasons, not only the quality of the metal is important, but also proper operation. Here are the main recommendations:

Use only dry hardwood firewood (alder, birch). Wet firewood creates soot, which promotes corrosion and reduces heat output. Avoid conifers (pine, spruce), as they release a lot of resin that clogs the chimney.

Clean the ash box after each sauna session. Ash attracts moisture, which causes metal to rust from below, even if the stove is not being fired. Free air access through the grates protects them from overheating and deformation.

Clean the internal channels of the chimney and stove at least twice a year. The soot layer acts as an insulator, forcing you to use more wood and overheat the metal unnecessarily.

Do not overload the firebox with wood to the very top. It is optimal to fill 2/3 of the firebox volume. Too intense burning will put unnecessary stress on the metal, causing it to crack or burn out.

Review the sauna stones once a year. Cracked stones crumble and block the air flow between the walls of the boiler, creating local overheating points. Replace damaged stones with new ones.

Tip: If you do not use the sauna in the winter, make sure that the water tank is completely emptied to protect the system from freezing and bursting.