Sauna Rocks – How To Choose

Follow these helpful tips in choosing the right sauna rocks and accessories.

Looking to buy online? Check out Amazon’s selection + free shipping!

So why do the rocks you choose make a difference?  Your sauna stones actually play an integral role in the sauna experience.  Sauna stones affect the heat and the steam and also play a role in how safe your sauna is.

Here’s a simple lesson in petrography or rock science.  Rocks can be grouped into 3 main types – igneous, sedimentary, and metamorphic.

Igneous rocks formed in a molten environment and are usually the oldest rocks on earth.  They result from cooled magma and lava.  Examples range from pumice to granite, basalt, and dolomite.

Sedimentary rocks are formed as layers of compacted sediments.  They break easily and are light weight.  Examples of sedimentary rocks are sandstone and shale.

Metamorphic rocks are heavy and dense.  Typically, they started out as sedimentary rocks that were changed by heat and pressure.  Examples of metamorphic rocks are marble, slate, and gneiss.

And why is this important  for your sauna?   Here’s why . . .

How To Choose Sauna Rocks

sauna rocks

Available on Amazon

Sauna rocks, or Konnos, determine whether your sauna heat is right and whether the steam is comfortable and effective.  And, from a sauna safety standpoint, they determine the risk and danger from exploding rocks.

The best rocks for your sauna are igneous rocks.  Not the porous ones but the dense, rough, uneven rocks.  Don’t choose rocks from wet environments like river beds that may have water trapped inside.  This water turns to steam when you fire up your sauna and can cause rocks to explode. If you are looking to buy safe sauna stones online, check out our page about the best sauna stones on Amazon.

Heavy and dense stones tend to produce more consistent heat and hold the heat better to produce steady steam.  How do you determine if they are dense enough?  Try hitting them with a hammer  or dropping them from waist level to a hard surface a few times (wear eye protection).  If they do not break or perhaps only chip a little, they’re good.

Another way to test the rocks is by creating a fire outdoors and placing stones in the fire making sure they reach a temperature of at least 212°F.   Use tongs and plunge the rocks into a bucket of cold water.  Wait for them to cool and then inspect them for cracks or breaks.  Weak stones will not respond well to the extreme changes in temperature.

You want your rocks to gradually heat up and release heat slowly, so choose the right size sauna stones.  A good rule of thumb is to select sauna rocks that are about 1/2 the size of your fist to as large as 3 times the size. It can help to have a variety of sizes so you can stack the stones nicely within the sauna heater.  Also, they should fit together in the sauna heater tray so that water does not pool there. Arrange the stones with the largest stones at the bottom and the smaller stones toward the top. Making sure that the stones are not placed too far apart will allow the rocks to catch the water poured over them and not allow the water to drip down to the bottom of the heater.

You may also want to pay attention to unpleasant smells coming from rocks.  Some stones contain minerals that give off foul odors when heated.

How To Prepare Sauna Rocks For First Use

You should prepare your sauna heater stones prior to using your sauna the first time.  First, wash the rocks off by running clean water over them in a bucket.  Continue until the water is running clear.

Next place the rocks loosely in the heater.  The heater rocks need to be loosely placed to allow air to circulate freely through them.  If the air doesn’t flow, the heater could overheat and flip the limit switch on the sauna heater.  If this happens, let the heater cool, reposition the rocks, and reset the switch.

sauna rocks

Aleko Sauna Rocks on Amazon

Replacement Sauna Heater Rocks

Perfect for most models of sauna heaters. 40 lbs of high-quality Aleko sauna stones.

Peridotite is a dense, course-grained igneous rock. Only igneous peridotite stones should be used in a sauna heater.

$140 & FREE SHIPPING on Amazon Shop Now >


Sauna replacement stones

Baltic Leisure Stones on Amazon

Sauna Replacement Stones

Baltic Leisure sauna stones. 30 lbs box of igneous dolerite rock selected to withstand rapid heating and cooling experienced in a sauna.

$33 & FREE SHIPPING on Amazon Shop Now >



Looking to improve your at-home sauna?

Check out the best electric sauna heaters here


Check out some great Sauna Accessories available on Amazon

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