Things to consider when choosing a wood burning heater
When choosing a wood burning sauna heater, it’s a good idea to keep a few basic points in mind to ensure that your sauna is functional, safe, and tailored to your personal preferences.
How much heating power is needed? Do you prefer a stove that produces hot, intense steam, or one that generates plenty of soft steam? What should you consider when positioning the stove? And how do you ensure safety distances are met in your sauna? See below for tips on choosing a sauna heater.
Heating power
When choosing a sauna heater, the most important factor is usually the heating capacity. The easiest way to determine the required capacity is to calculate the cubic volume of your sauna room, taking into account not only the sauna’s dimensions but also the impact of materials and uninsulated surfaces. Even a single glass door or a small window can have a significant impact on the required heating capacity.
- Measure the length, width, and height of the room, and multiply these measurements together. For example, 2.0 m × 2.5 m × 2.3 m = 11.5 m³.
If the sauna room has uninsulated surfaces, such as glass walls, glass doors, concrete, or brick, multiply their total area by a factor of 1.2. Add this value to the sauna room’s cubic volume.
- For example, a glass door measuring 0.9 m × 2.1 m = 1.89 m² is multiplied by 1.2, resulting in a calculated volume of 2.27 m³.
- Add this value to the sauna's cubic volume: 11.5 m³ + 2.27 m³ = 13.77 m³.
In this example, the calculated volume of the sauna room is around 14 m³. In this case, you should choose a sauna heater with a heating capacity sufficient for saunas of approximately 10–20 m³. For example, the Cilindro 20 or the traditional 20 Pro heater.
- If the interior surfaces of the sauna room are made of log, multiply the cubic volume by a factor of 1.5.
You can use our sauna calculator to help you calculate the volume of your sauna room.
Calculate the volume here - Harvia Sauna Calculator
Löyly "steam" and heating rate
Traditional sauna stoves - Quick heating and intense steam
In traditional wood burning heater models, the stone compartment is fairly small, and the heater typically holds only a few dozen kilograms of stones. The sauna room heats up quickly and the high temperature of stones allows for more intense steam bursts (löyly) when needed, depending on the model.
Choose a traditional heater model if a quick heating time or hot steam (löyly) is your top priority. For this purpose, we recommend heaters from the Pro series, such as the Harvia 20 Pro.
Pillar stoves with a large stone mass – Moist steam and a stylish look for your sauna room
The large stone mass of pillar-style heaters allows for soft, moist steam (löyly) while adding a striking visual element to the sauna room. Heating the sauna room takes a little longer because the stones store a great deal of heat. On the other hand, the large mass also retains heat well throughout the entire sauna session.
Choose a pillar-style heater if you appreciate a soft and steam-filled sauna experience, or if you want to focus specifically on the sauna room’s interior design. For this purpose, we recommend the steel-colored Cilindro wood burning heaters or Legend series.
Many factors affect the heating rate
The time it takes for a sauna room to heat up is significantly affected by factors such as surface materials, insulation, ventilation, the amount of draft in the chimney and the quality of firewood. For this reason, specific heating times have not been defined for different heater models.
Heater location and safety distances
Heater location
The location of a wood burning heater in the sauna room is determined by the position of the chimney. When positioning the heater, you must take into account the safety distances for both the heater and the chimney, as well as the functionality of the floor plan. If the sauna room also serves as a washing area, be sure to leave enough floor space for washing.
For chimney-type water heaters, the safest option is a model equipped with a separate water hose and faucet, such as the Legend or Cilindro water heater. With this solution, the hot water faucet can be placed further away from the heater, in the desired location.
Safety distances
The safety distances specified in the user manual must be strictly observed! Failing to maintain these safety distances may result in a fire hazard and risk of injury. If necessary, you can reduce the safety distances by using model-specific protective walls, which are sold separately. For the chimney/smoke pipe section, it is possible to reduce the safety distances by using a chimney-type water heater or a stone basket.
In most cases, a separate protective base is required under the heater, as the heater also gets hot from the bottom. In addition to wooden floors, other materials may also require a protective base — for example, the waterproofing beneath a tile floor could be damaged by excessive heat.
Let's sauna!