Why do sauna stones need to be replaced?
Sauna stones are one of the most important, yet often overlooked, parts of a sauna. Many remember to clean the benches, wash the sauna, and maintain the heater, but the sauna stones might remain the same year after year. In reality, it is precisely the stones that significantly affect the quality of the steam in the sauna.
Sauna stones are not eternal. They are constantly exposed to intense heat, rapid temperature fluctuations, and water. When water is thrown onto hot stones, the surface of the stone cools momentarily while the interior remains hot. This stresses the stone repeatedly. Over time, the stones begin to crack, crumble, and compact inside the heater.
As sauna stones wear out, the quality of the steam deteriorates. Old and crumbling stones do not retain heat in the same way as stones in good condition. The steam can become sharp, dry, or uneven. The sauna no longer feels as pleasant, even if the heater is otherwise in good order.
Old sauna stones stress the heater
The purpose of sauna stones is not only to produce steam. They also protect the heater and help distribute heat correctly.
When the stones crumble, small stone chips and dust settle around the heating elements or firebox structures. In an electric heater, this can prevent air circulation around the elements, causing them to overheat. In a wood-burning heater, poor-condition stones can weaken heat retention and make the steam more uneven.
A too densely packed stone mass prevents air from circulating in the heater. In this case, the heater has to work harder, heat is not distributed correctly, and the lifespan of the heater can be shortened.
When should sauna stones be replaced?
The replacement interval for sauna stones depends on how often the sauna is used.
In a home sauna, the stones should be checked at least once a year. If the sauna is in heavy use, such as at a cottage, rental property, housing association, or for business use, the stones should be checked and replaced more often.
Sauna stones should be replaced if:
- the stones have cracked
- the stones crumble in your hand
- stone dust accumulates at the bottom of the heater
- the stones have compacted into a dense mass
- the sauna heats up slower than before
- the steam feels weak, dry, or sharp
- the heater makes unusual noises when heating
A good rule of thumb is: if you don't remember when the sauna stones were last replaced, they should be checked.
Relaying the stones is important
It is not always enough to simply add a few new stones on top of the old ones. The stones should be completely removed, their condition checked, and then relaid.
When relaying, it is important that air can circulate between the stones. Stones should not be packed too tightly, as excessively dense packing prevents air circulation and stresses the heater.
In an electric heater, the stones should be laid so that the heating elements do not bend or get squeezed. In a wood-burning heater, the stones are laid so that heat can rise evenly through the stone mass.
The right type of sauna stones matters
Not all stones are suitable for a sauna heater. A sauna stone must withstand high temperatures, rapid temperature fluctuations, and repeated water throwing.
One should not randomly collect stones from nature for the heater. Incorrect types of stones can crack quickly, crumble, or at worst, break under heat.
High-quality sauna stones withstand use better, retain heat well, and help produce a more even steam.
Small maintenance, big impact
Replacing sauna stones is a small maintenance task, but its impact on the sauna experience can be surprisingly significant. New and correctly laid stones improve the steam, help the heater function properly, and can extend the heater's lifespan.
A good sauna is created by many factors, but sauna stones are one of the easiest things to get right. If the steam no longer feels the same as before, the problem might just be with the stones.
At Saunaproshop, you'll find high-quality sauna stones and advice on choosing the right type and quantity of stones. We are happy to help you choose the right stones for your heater so that your sauna functions as it should: warmly, softly, and with good steam.