Piling the stones

Changing sauna stones makes the sauna heat up faster – saving energy & time

When you are in the sauna, have you ever thought about the effect that the sauna stones have on the sauna, let alone on the sauna’s energy consumption? The sauna stones play a very central role in every sauna session, and when kept in good condition – sauna stones improve the speed of the heating of the sauna, as well as the whole sauna experience while saving energy. For this reason, it’s important to make sure every year that the stones are in good condition and laid in the heater correctly.

Harvia Vulcanite heater stones

Remember to maintain your electric heater annually

Just like a car, whether it’s Porsche or an Opel, the sauna heater also needs annual maintenance to be safe to use. If the heater seems to be in good condition externally, remember to also check the condition of the sauna stones regularly. At the same time, you can check that the heater's heating elements are working correctly. The poor condition and crumbling sauna stones can break the heating elements of the electric heater, in which case the heater will require maintenance by a professional or at worst, a replacement. If sauna stones are packed too tight into the stone compartment of the heater, they will block the air circulation of the heater, meaning that the heater will require more time and energy to heat the sauna. 

If the sauna stones are in good condition, they don’t need to be replaced but they should be returned to the heater loosely enough so that the air can circulate properly in the heater. In this case, the sauna heats up faster and the heater uses less energy to heat the sauna. By re-stacking the sauna stones, you also ensure that the sauna stones don’t burden the heating elements of the heater. 

Harvia Cilindro electric heater

When reaching a desired temperature, there are significant differences in the efficiency of the sauna session – which depend on the condition of the stones and how they are stacked in the heater

Our test took place in a 10m3 sauna equipped with a Harvia Cilindro PC70E 7kW heater. We tested both new and old sauna stones, each in loosely laid* and tightly stacked configurations in the heater.  Each of the loose-laying stacks took 80 kilos and the tight-laying stacks took 90 kilos of sauna stones. 

In the test, the biggest differences in the temperature of the sauna came from the heater with loosely laid stones. The air circulation was better in the heater with loosely laid stones, which means that more air can move from the heater into the sauna room, heating it faster. Additionally, when the heater was heated up with new, loosely laid stones, the heater's heating elements reached a maximum of 580 degrees Celsius. Compared to the old tightly stacked stones, the heating elements heat up to 680 degrees. The heating elements with loosely laid old stones produced a maximum heat of 640 degrees. These differences in temperature suggest that loosely-laid sauna stones extend the service life of the electric heater’s heating elements – as they do not require such high temperatures. 

A difference of about 10 degrees in the temperature of a sauna room with a size of 10m3 was observed after one-hour measurement between the new tightly stacked and loosely laid stones. With the new tightly stacked sauna stones, the sauna temperature was around 60°C, while with the new loosely laid sauna stones the sauna temperature was around 70°C after an hour. 

As a summary of the test results, it can be stated that replacing and re-stacking the sauna stones improves the heater’s operation and prevents premature damage to the heating elements. The improved heating capacity of the electric heater means less energy consumption. 

*The loose placement performed in the test refers to laying the stones into the heater according to the instructions. The stacking was done without excessive placement of the stones. 

Piling stones to The Wall heater

Easy tips for the annual inspection of the sauna stones

-Check if there are any pieces of stones visible underneath the heater. If pieces are found on the floor, the condition of the stones should be inspected 
-Check the condition of the sauna stones by knocking two stones against each other. If the stones crumble or are discolored, it’s time to replace them with new ones 
-Wash good condition or new sauna stones from stone dust and place them loosely enough into the heater 

Olivine diabase sauna heater stones

Sauna stones for different purposes

There are several different sauna stone options available on the market which are suitable for slightly different purposes. The most traditional type of sauna stone is olivine diabase, which is suitable for all types of sauna heaters. The structure of the olivine diabase withstands strong temperature changes and has excellent heat storage capacity, as well as thermal conductivity. Traditional sauna stones are available in two different sizes, so always check the correct sauna stone size according to the manufacturer’s recommendations for your heater. 

Harvia Legend pillar heater

Vulcanite sauna stones

Just like olivine diabase, vulcanite is a hard and durable natural sauna stone that doesn’t differ much from the traditional sauna stone. The special feature of vulcanite stones is their color which is very dark and when wet, the stones shine almost black. Vulcanite stones are suitable for all heaters, and they are available in two different sizes just like the traditional sauna stones.  

Heat treated Elite sauna heater stones

Elite Pro Heavy Duty sauna stones

Elite Pro Heavy Duty sauna stones are specially made from the highest quality Finnish olivine diabase which has been heat-treated at around 1000 degrees of Celsius. These sauna stones are perfect for saunas that are in heavy use, thanks to the heat treatment. The heat treatment modifies the small micropores of the stones so that they store water and give moist sauna baths with every sauna session. The service life of Elite stones is many times higher than of the traditional stones. 

rounded sauna stones in picture

Rounded sauna stones

Rounded olivine diabase is a beautiful stone that offers very soft and pleasant sauna baths as the water flows from the surface stones to the lower stones. With heaters that have small space for stones, it’s recommended to use the round stones as the top layer of the same-sized traditional stones. This increases the water vaporization surface lower in the stone space.  

White decorative sauna heater stones

Decorative sauna stones

The decorative sauna stones are, as their name suggests, intended as a decoration element for the upper part of the sauna heater. Decorative stones are available in white as well as in red granite. A maximum of one boxful of decorative stones are laid loosely as the top stone layer of the heater. The contact of the decorative stones with the heating elements of the electric heater must be avoided. 

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