A guide to environmentally friendly sauna bathing

Our guide to environmentally friendly sauna bathing contains basic information on how sauna builders, renovators and users can do their share to reduce their ecological footprint. It’s the little things that count!

Harvia products are designed and manufactured with the environment in mind. Sustainable choices are not only good for the environment, they are also good for people.

Consider these factors when selecting a sauna heater

  • It is extremely important to select a heater or stove with the correct output. The consumption of firewood or electricity increases if the stove or heater is either too small or too large.
  • If the walls or ceiling of your sauna contain non-insulated stone, glass or equivalent surfaces, the stove or heater will require more power.
  • For each non-insulated square metre, add 1.2 m³ to the volume of the sauna.
    If the interior walls of the sauna room are made of non-insulated logs, multiply the cubic volume by 1.5.
  • Consider your personal sauna bathing preferences. For example, if you use the sauna often, choose a heat-storing electric heater that is always ready. Harvia Forte is an economical sauna heater when used frequently. It features efficient thermal insulation that allows the heater to keep providing ample heat with little electricity. In between baths, the heater works as a normal radiator in the sauna. The heater’s properties are the best in saunas with good thermal insulation and no dense materials (such as concrete, logs or glass blocks).
  • Save in water heating costs by using stoves equipped with water tanks, such as the woodburning 20 LS Pro and 20 RS Pro stoves. The 30-litre tank heats up the water while the stove is being heated for bathing.

Solide Compact Harvia 20 ProSauna stones

All Harvia electric heaters and woodburning stoves must use massive, split-face sauna stones, as they store plenty of heat and make the water thrown onto them vaporise efficiently on the broad fracture surface.

Angular split-face stones also allow for loose placement of the stones. Split-face sauna stones are an ecological choice. Between quarrying the stones and piling them onto the heater, split-face stones involve fewer environmentally harmful stages than processed (such as rounded stones) or industrially manufactured stones (such as ceramic stones).

Harvia sauna stones are available in two sizes. The 5–10-cm stones are suitable for wall-mounted electric heaters that have a lower power output. The bigger sauna stones, which are 10–15 cm in size, are suitable for woodburning stoves and larger electric heaters as well as heat-storing electric heaters (such as the Harvia Forte heater). High-quality, undamaged stones provide proper and soft heat and steam. Good stones also boost the lifespan of the resistors.

Use of the sauna heater

Proper maintenance gives the heater a longer lifespan. Replace the stones at least every two years and more often if the sauna is in frequent use. Pile the stones correctly. It is a good idea to rearrange the stones between replacements, as they tend to sink slightly over time. At the same time you can remove any small pieces of stone from the bottom of the heater.

Electric sauna heater

Do not heat the heater for longer than necessary.
• Turn the heater off when you are finished bathing. However, it is practical to let the residual heat dry off the sauna’s wooden surfaces.
• Do not heat the sauna too hot.
• When you replace the electric heater with a new one, take the old heater to a recycling facility.

Woodburning sauna stove

  • Start the fire on top of the firewood. Read more about cleaner burning of Wood.The most critical phase for emissions is the starting of the fire and the first stage of burning. Starting the fire on the top is proved to be the best alternative, as then the wood components gasifying due to heat from the kindlings flare up and nearly everything that gasifies also burns. If you start the fire under the firewood, all the wood will heat up and gasify simultaneously. If this happens, the air in the chamber is not sufficient for controlled burning and some of the gas flows into the flue and escapes outside without burning. This requires more wood and generates more emissions. Too slow a combustion reaction is also a bad alternative, because it does not allow the temperature to rise high enough and the burning is not perfect.
  • Start off by laying small pieces of wood horizontally and ensure that air can circulate between them. Add larger pieces of wood for the second batch. Ensure that the chamber is not too full and approximately one third of its height consists of free airspace. Lay the kindling (firelighters, a handful of sticks, birch bark or newspaper) on top of the wood and set it on fire.
  • Wait until there are no more flames left in the fire chamber before adding a second batch of firewood on top of the embers.
  • Good firewood is dry, over a year old, unpainted and not impregnated. Do not use materials that have a high thermal value, such as chipboard, plastic, coal, briquettes, pellets, etc.

Sauna bathing

  • Save energy when several people bathe at the same time. This way the heater doesn’t need to be kept on for several hours.
  • Do not heat the sauna too hot, 60–80 ºC is enough.
  • If the sauna room has a window, keep it closed during bathing. An open window causes significant heat loss and increases energy consumption.
  • The wooden surfaces have a longer lifespan when you make sure that the sauna room is properly dried after bathing. Depending on the size of the sauna room, it is usually not necessary to leave the heater on – residual heat is enough to dry the room.

Taking a shower

Showering also requires heating energy and, of course, water. Use hot water sparingly in bathrooms and turn off the tap while washing. The Harvia 20 LS Pro and Harvia 20 RS Pro stoves, which are perennial favourites in cottage saunas and equipped with a water tank on the side, are practical stoves that save water heating costs. Water heats up in the 30-litre water tank while the stove is being heated for bathing.