Harvia Pro 20 LS woodburning heater

How do you choose the right wood-burning heater?

A wood-burning heater is the heart of a sauna and offers a beautiful adornment for the sauna in addition to atmosphere-creating steam. When choosing a heater you need to consider the size of the sauna as well as the materials within the sauna. A good rule of thumb is to think that 1 kW of heating power is required per cubic meter of the sauna, and the need for power increases when the sauna has glass surfaces or surfaces that store heat. When choosing a wood-burning heater you should consider the size of the sauna room as well as your sauna preferences and the heater's intended use and location. Is there running warm water available for the sauna or is a heater with a water tank needed for warm washing water? The location of the heater is determined by its installation method and the protective distances in the sauna. It's possible to reduce the protective distances with the help of separately-sold protective wall panels for the heater.

The calculatory sauna volume

The volume and structures of the sauna affect the selection of heater power. The power requirement increases if there are window surfaces or heat-storing surfaces such as brick, concrete or massive logs in the sauna.

Sauna room size


Sauna bench closeup

The calculatory volume of your sauna is

0 ft³

Men enjoying Harvia Legend GreenFlame woodburning heaters löyly

Steam preferences

Once technical issues have been dealt with regarding the heater, the important question of steam preferences arises. The steam from wood-burning heaters can be roughly categorised as soft or hard steam. The amount of stones in the heater largely determines what kind of steam the heater offers.

Harvia Solide sauna with Legend GreenFlame woodburning heater

Soft steam

Heaters with a large amount of stones offer bathers soft, moist and plentiful steam. The large stone mass keeps the temperature of the sauna moderate, and the stones reserve thermal energy for a long time, offering more relaxation.

Harvia Pro 20 woodburning heater

Hard steam

For lovers of hot and sizzling sauna, we recommend traditional wood-burning heaters with a smaller amount of stones than pillar model heaters. A smaller amount of stones heats up quickly and you feel the steam on your skin with every throw of water.

Harvia Linear 22 GreenFlame environmentally friendly heater

Heaters with a water tank

A wood-burning heater with a water tank is the perfect choice for a cabin sauna where warm water is not available for washing. As the sauna heats up, the water also warms up and is ready for washing. In heaters with a water tank, remember that the tank must not be empty when heating the sauna, to avoid damaging the water tank. The selection includes models where the water tank is in front of the heater or on either side. Chimney-heated water tanks are also available as heater accessories.

Heater installation

The location of the wood-burning heater in the sauna is determined by its installation method. In a back-flow heater connected to a masonry flue, it is good to remember the flue connection and its height. Various connection pipes are available for the heaters, which can be used to safely connect the heater to the flue. A vertical heater also requires a light metal flue, such as Harvia's steel chimney set, which is suitable for a temporary sauna. The steel pipe set for a traditional sauna includes a 1.5-meter long steel pipe and an accessory box with a meter of non-insulated flue pipe, rain cap, rubber rain collar, rain collar attachment kit, steel feed-through collar for the inner ceiling, feed-through insulator and cover. The length of the steel pipe can easily be extended with additional modules. Please note that the heater must always be installed in accordance with the manufacturer's installation and safety instructions.

Increase heater safety with heater accessories

Wood-burning heaters are available with many safety-boosting accessories, such as protective walls and protective base. The need for additional accessories is determined by the heater's protective distances, which can be reduced with the help of protective walls. In addition, it's good to remember the protective base for the heater if the heater is installed on a waterproof tile floor or wooden floor.

Harvia 22 GreenFlame detail

Cleaner burning of wood

Harvia has been invested for a long time in the product development of wood-burning heaters that promote the cleaner burning of wood. Harvia's GreenFlame heaters act as pioneers for low-emission stoves. In GreenFlame heaters, carbon monoxide emissions from burning wood are 70 percent lower and small particle emissions are about one-fifth lower compared to a heater model of a similar size.

A checklist for the buyer of a wood-burning heater

  • Calculate the area of the sauna remembering to take into account sauna materials

  • Choose the right heater for the sauna size

  • Decide on the location of the heater in the sauna and remember safety distances and instructions

  • Consider the location of the chimney in the sauna

  • Consider steam preferences

  • Decide on the need for warm water in the sauna

  • Finalize installation method

  • Choose accessories

  • Choose heater stones

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