To make löyly, first check that the heater allows water and that the venue permits you to pour it. Use a ladle to spread a small amount of clean, warm water gently across the hot stones. Let the steam settle before adding more. In a shared sauna, ask the other people before you start.
What is löyly?
Löyly, also written as loyly, is the Finnish term for the steam produced when water meets hot sauna stones, and for the act of creating it. The stones hold heat. When you add water, that stored heat turns it into vapour, which spreads through the sauna.
The main change you notice is humidity and the feeling of heat. SAUNOM explains that the room can feel hotter even though the thermometer barely changes. Adding water also cools the surface of the stones slightly, so more water does not simply mean more heat.
Think of löyly as a gradual adjustment rather than a large splash. The amount of water, the heat stored in the stones and the pauses between pours all affect the steam you experience.
Check the heater and the sauna rules first
Before you pick up the ladle, check that water is allowed on the heater. SAUNOM notes that some electric heaters are designed for dry use only, as are most infrared cabins. Stones alone are not a reason to assume that you can pour water. Check the heater manual for permission to use water.
In a shared sauna, read the posted instructions. The self-löyly guide from Samurai Sauna Magazine explains that facilities may limit the amount of water, set an interval between pours or prohibit users from pouring it themselves. Follow those instructions rather than a general guide.
Ask the other people in the room before adding water, and wait for an answer. The humidity changes for everyone, not just the person holding the ladle. This check matters even when you only plan a small pour.
How do you pour water on the stones?
Start with fully heated stones and a small amount of clean, warm water. Use the amount permitted by the heater instructions or the venue. If you are unsure about the quantity, the self-löyly guide recommends using less rather than more.
- Take a small amount of water with the ladle.
- Pour gently and slowly across the stone surface.
- Spread the water rather than pouring it all into one spot.
- Pause while the steam rises and disperses.
- Let the stones dry between pours before considering more water.
Iglucraft recommends slow, evenly distributed pouring. Samurai Sauna Magazine gives similar guidance: a thin spread across the stones, followed by a pause. Neither approach calls for emptying a bucket onto the heater.
Build the humidity gradually. Repeated pours in quick succession can make the heat feel sharply more intense. Too much water can also cool the stones and leave water pooling in the heater rather than producing the steam you intended.
How much water should you use, and how often?
The sources agree on small amounts, but their suggested quantities and intervals differ. Narvi recommends approximately 50–100 ml at a time, with the amount depending on sauna size, heater capacity and your preference for steam intensity. For residential saunas up to 10 cubic metres, it suggests beginning with half a ladleful.
SAUNOM describes one or two small ladlefuls per pour. It also reports guidance of around 80 ml from HUUM. These are starting points, not a replacement for the instructions for the heater you are using.
Timing differs too. Narvi suggests 30–60 seconds between applications, while SAUNOM suggests 60–90 seconds. There is no single interval shared by those sources. Follow the venue or heater instructions first, allow the steam to disperse and avoid repeated pouring while the previous addition is still affecting the room.
What water should you use?
Use clean, fresh water. SAUNOM and Iglucraft recommend warm water for pouring onto the stones. SAUNOM also says not to use salt water, pool water or anything flammable.
Narvi says tap water works in most locations, but advises avoiding water with high mineral content or chlorine. In a hard-water area, it suggests considering filtered water. Mineral deposits can affect how the stones transfer heat and can contribute to their deterioration. Check the heater manufacturer's water requirements rather than assuming every water supply suits every heater.
Plain water keeps the process straightforward. The essentials remain the same: check permission, use a modest amount, pour gently and wait. You are adjusting the humidity a little at a time, not trying to produce the largest possible cloud of steam.
Questions people ask
- Does löyly raise the sauna temperature?
- It mainly raises humidity and how hot the sauna feels. SAUNOM explains that the thermometer may barely change, while the water slightly cools the stone surface.
- Can you pour water on an electric sauna heater?
- Only if its instructions allow it. Some electric heaters are designed for dry use only. Check the manual, and follow any venue rules about who may pour water.
- Should you ask before pouring water in a shared sauna?
- Yes. Ask the other people and wait for an answer. The steam changes the humidity and perceived heat for everyone in the room.
- How long should you wait between pours?
- Follow the heater or venue instructions. Published guidance differs: Narvi suggests 30–60 seconds, while SAUNOM suggests 60–90 seconds. Let the steam disperse and the stones dry rather than pouring repeatedly.
- Can you use tap water for löyly?
- Narvi says tap water works in most locations. It recommends considering filtered water in hard-water areas and checking the heater manufacturer's requirements. Use clean water, not pool water or salt water.