The piling of the sauna stones has a great effect on both the safety and the heating capability of the heater, especially for electric heaters. Always check the right heater stone size and amount from the manual included with the heater. Smaller 5–10 cm diameter stones are usually used in electric heaters as they fit well between heating elements. Smaller stone sizes are also used on the top layer of woodburning heaters as they create more surfaces for steam generation. Larger 10–15 cm diameter stones are used in woodburning heaters and also in selected Harvia electric heaters with larger stone capacity.

Start the stone piling by washing off the dust from the stones before placing them into the heater. Be aware, that the type and the shape of the heater affect the piling structure of the stones. Your best guide for doing this properly for your selected heater is to follow the instructions included in the heater manual. Here are a few important tips for piling sauna heater stones for all Harvia heater types.

• Do not drop stones into the heater
• Arrange the stones evenly and loosely to ensure air can flow between them
• Do not form a high pile of stones on top of the heater
• Do not place stones on top of the heater frame
• Place elongated stones vertically in the heater

Also note for electric heaters:

• Do not wedge stones between the heating elements
• Pile the stones so that they support each other instead of resting heavily on the heating elements
• Support the heating elements with stones so they don’t bend

New stones may give the sauna a natural stone scent during the first heating. After piling the stones, we recommend heating the sauna and pouring enough water to douse all the stones. This will help remove any unwanted scent from the stones after the initial use.