Because the heater comes to life with the stones, their correct choice and maintenance are necessary for a pleasant and safe sauna experience.

The heater is the heart of the sauna, and so the quality, size and shape of the stones in the heater matter. Every sauna bather wants high-quality steam, so sauna stones must have certain characteristics. The following questions are helpful in choosing the right stones:

  • How do they conduct heat?
  • How well do the stones tolerate heat?
  • What sizes of stones are needed?
  • How do the stones hold heat?
  • What shape of stones does the heater require?
  • How to place the stones in the heater?
  • How to produce the scent of the stones?

The more often the sauna is heated, the more demanding are the criteria for choosing the stones. The stones must be resistant to regular heating and steaming. If the heater is used every day and is turned on for several hours at a time, the stones must be replaced at least once a year. The way the sauna is heated also has an effect on how often the stones must be changed.

Many shapes of stone

Sauna stones usually come in a variety of shapes and sizes. Placement of the stones in the heater is made easier by first spreading out the stones on a mat or paper on the sauna floor near the heater. This makes it easy to choose the different sizes of the stones, and the right size and shape of each stone for placing in the heater. It is a good idea to use gloves when filling the heater with stones.

In general, it should be remembered that the stones need to be sparsely placed to ensure adequate air circulation in the heater. In wood-fired stoves, larger stones are in the bottom of the heater. The higher up the heater is filled, the smaller the size of the stones should be. The small stones on the top vaporize the water better, as they provide a larger total surface area than large stones.

Photo: Tuomas Pesola / Sauna from Finland
Parhaat Löylyt sauna stones

All the stones supplied by Parhaat Löylyt (Finnish for ‘the best steam’) are made from the best rock available, such as olive diabase from the Satakunta region of Finland. Due to its ophitic (i.e. layered) structure, this type of stone has proven through use to be the most durable of the safe types of sauna stone on the market. They are suitable for all types of heater.

Parhaat Löylyt sauna stones are selected with a strong emphasis on quality. The Geological Survey of Finland controls the quality. Parhaat Löylyt stones are pre-washed and hand-selected quality products. The stones are always safe, clean and ready for use. Changing these ready-cleaned stones in heaters is easy and fast.

Article written in cooperation with SAUNA-EUROX.

Read the complete instructions and more info about sauna maintenance from the Authentic Finnish Sauna Experience Quality Handbook. The book available for ordering in

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