A Complete Guide to Wood Fired Sauna Stoves

How a Wood Fired Sauna Stove Works

The wood fired sauna stove achieves efficient room heating through the combustion of wood and the diversion of flue gas. Taking the Alphasauna wood fired sauna stove as an example, wood combustion releases heat and large volumes of high-temperature flue gas. Part of this heat is transferred to the air via the stove body, rapidly raising the sauna temperature. The remaining heat and high-temperature smoke first enter the heat exchange channel above the firebox before reaching the chimney. Here, they transfer heat to the surrounding metal tube walls and the sauna stones stacked upon them. Once thoroughly heated, the sauna stones continuously release thermal energy, helping maintain the temperature for longer.

Advantages of Wood-Fired Stoves

Although convenient electric sauna heaters have become increasingly popular, wood fired sauna stoves are still the best choice for many sauna enthusiasts. They represent the most authentic Finnish sauna and the primal connection to nature.

High Heat Output

Electric sauna heaters have a fixed power rating and generate a relatively constant amount of heat. In contrast, the heat output of a wood fired sauna stove depends on the type and quantity of firewood used, as well as whether it burns fully. When adequately fueled and burning efficiently, a wood-fired stove typically generates more total heat than an electric heater and can heat a sauna room to 240°F.

More Efficient Stone Heating

As high-temperature flue gas lingers and flows within the heat exchange channel, it radiates significant heat to its surroundings. Sauna stones are stacked precisely around this channel. This design enables secondary utilization of the flue gas heat, significantly enhancing heat transfer efficiency. Unlike an electric furnace, which relies on a heating rod to heat the stone, a wood-fired stove heats the stones as if “baking” them with high-temperature smoke, making them hotter and more uniform overall. And the steam is more intense when watering.

The ambiance of a traditional sauna

From chopping wood and building the fire to stepping into the warm sauna room, tending the flames, splashing water, and patting oneself with birch branches, the process of using a wood fired stove is a unique ritual in itself. This ritualistic experience is integral to the traditional Finnish sauna. The wood-burning sauna stove offers a full sensory experience:
Watch the flames dance through the stove door, hear the crackling of burning wood, and smell the natural aroma of burning wood—completely different from the artificial scent of essential oils. This raw, natural atmosphere is incredibly relaxing

Without electricity

Wood fired sauna stoves only consume wood, are not affected by electricity price fluctuations, and do not require complex circuits to be installed.

Key considerations before installation

Before you decide to install one, you need to consider whether your space and lifestyle are suitable for a wood fired sauna stove.

Local safety regulations

Before installing a wood fired sauna stove, you need to check your local building codes and fire regulations to see if they have any special requirements for open-flame appliances, whether permits are required, or whether there are any environmental restrictions. This is important preparatory work.

Space Requirements

Wood-burning sauna stoves rely on open flames, posing significant fire risks. Therefore, fireproof measures are essential. The stove must be kept a safe distance from walls, roofs, and surrounding combustible materials. The floor and walls surrounding the stove must also be paved with heat-resistant materials.

If you choose an Alphsauna wood fired outdoor sauna with an integrated stove, the manufacturer has already taken care of the fireproof issues. Our wood fired stoves feature a fireproof base and an insulating back panel to prevent prolonged heat from baking the wood structure. The chimney section penetrating the roof features a chimney thimble to prevent direct contact with the wood roof.

Additionally, you still need to ensure the foundation supporting the sauna kit is firm enough and that there is enough outdoor space for ventilation. Most importantly, you shall have a place to store firewood.

Lifestyle Match

It’s undeniable that using a wood fired stove takes more time than an electric one. First, while wood fired stoves offer high heat output, they may be slow to warm up. This is because it takes time for the wood to burn sufficiently to reach high temperatures within the stove body—a process influenced by firewood type, dryness, and the amount of wood fed. Second, you must prepare and store firewood in advance. Third, cleaning wood debris or ashes is required after each use. Furthermore, if you’re a first-time user, you may need to learn some fire-starting techniques. These so-called “inconveniences” may be seen as flaws, yet the very things that make it closer to a traditional sauna.

Iron Stove Body

Modern wood fired sauna stoves are mainly composed of the stove body, chimney, door, grate, outer shell, and other structures. For the most critical components—the stove body and chimney system—we employ a combination of a thick iron stove body and stainless steel chimney, which has superior performance.

Stove Body

The iron stove body withstands high temperatures and conducts heat rapidly. When burning wood, the firebox temperature can reach 800-1200°F. The cast iron construction not only resists deformation under the high temperature of burning wood, but also can efficiently transfer heat to the sauna stones and the air.

Chimney

Wood smoke from burning contains a high amount of acidic substances. When this smoke cools and condenses, it forms acidic condensation liquid. This condensate can corrode metal chimneys over time. Our stainless steel chimneys exhibit strong resistance to acidic condensate and high humidity, resulting in a longer service life. Moreover, stainless steel chimneys are lightweight, making them exceptionally easy to install.

Choice of firewood

Choosing wood is a fascinating part of a wood-fired sauna. Different wood species influence your sauna experience in terms of thermal properties, aroma, and combustion performance. We recommend using hardwoods with long burning times and high heat output as your primary fuel, such as birch, ash, and oak. Additionally, we suggest using some fast-igniting wood as kindling. Beyond this, firewood selection should follow the principle of adapting to local conditions. Use whatever high-quality hardwood is available in your area, but ensure the wood is thoroughly dried. 

Recommended firewood combinations

Kindling: Aspen/Alder
Main firewood: Birch/Ash/Oak/Other well-seasoned local hardwoods
Blending suggestion: Add a little apple wood/cherry wood to the main wood (for aroma). 

Absolutely prohibited

All chemically treated wood, such as plywood and painted wood, should be avoided in the sauna stove to prevent the release of harmful gases during combustion.

Safe Installation

Safety is the prerequisite for enjoyment. Before using a wood fired sauna stove, it must be installed by a professional in accordance with the installation instructions and local building codes.
1. Ensure all necessary installation permits have been obtained.
2. The entire sauna cabin has undergone fireproof treatment.
3. Ensure the fireproof back plate and base plate of the stove are properly installed.
4. Ensure the heater maintains a minimum safe distance from all combustible materials: at least 1.2 meters from the ceiling; at least 30-50 cm from seats; and at least 10 cm from walls.
5. The chimney outlet must extend 0.5 meters above the roof.
6. Ensure the sauna has a low-level air inlet and a high-level air outlet.

Operating Guide

Once you’ve installed your wood stove, it’s time to start your sauna! This is a complete guide to using a wood-fired sauna stove, covering preparation → lighting → use→ maintenance. This guide is perfect for a typical outdoor sauna.

Preparation before use

1. Before lighting a fire, check that the chimney is clear and that there is no excess ash in the firebox.
2. Keep flammable items (towels, wooden buckets, scented oils, etc.)away from the firebox.
3. Prepare dry firewood and kindling.
4. If this is your first time using a wood stove, we recommend having fire safety equipment ready (such as a bucket of water or a fire extinguisher).

Quick fire

Starting a fire is a bit of an art. We don’t recommend lighting a pile of firewood directly, as it usually won’t burn properly. Instead, you need to be patient and use some kindling, like bark or paper, to light some twigs. Start with the small branches and gradually add the main firewood. We recommend using the “thin-thick-thin” principle when placing firewood: Place the thinner pieces on the bottom layer, the thickest pieces in the middle layer, and then cover the middle layer with thinner pieces.

Post-processing

1. After using the sauna, stop adding wood and wait for the fire to burn out naturally.
2. Clean the ashes in the firebox and the ash drawer after the stove and ashes have completely cooled (usually until the next day)

Maintenance and Care

Taking a Harvia wood-burning sauna heater as an example, here are the maintenance methods:
1. Clean out ashes after each use.
2. Inspect the exterior of the sauna heater every six months for rust, cracks, or other signs of damage.
3. Check your sauna stones every six months and replace any that are cracked or damaged
4. Inspect the chimney every six months to keep it free from dust or blockages.

Creating Your Perfect “Löyly”

“Löyly” comes from Finnish and refers to the wave of steam rising from the hot sauna stones when water is poured onto them. Many sauna enthusiasts believe that the “Löyly” is the key to the entire sauna experience, and that the “Löyly” produced by a wood-fired stove is often softer, moister, and longer-lasting. A good “Löyly” is a gentle, long-lasting, yet intense heat wave. It should not be sharp or scorching, but rather an enveloping heat. The amount, frequency, and timing of the water pouring, as well as the number and temperature of the stones, all determine the quality of the “Löyly”.

H3 Choosing Sauna Stones

Thoroughly preheating the sauna stones is fundamental to a good “Löyly”. It’s not just about heating the air in the sauna room; the stones must be heated through and through, from the inside out. This typically requires waiting at least 30 minutes.

We recommend choosing heat-resistant, crack-resistant stones, such as volcanic rock or gabbro. Mix and match stones of varying sizes, stacking them loosely to ensure the heat from the flame penetrates.

Furthermore, more sauna stones generally produce a more comfortable “Löyly”. So choosing a sauna heater that accommodates a larger quantity of stones is also a good approach.

The amount, frequency, and timing of water splashing

Each splashing of water will raise the humidity and temperature in the room, so adjust the frequency based on your body’s sensitivity. Follow the principle of “small amount, multiple times” principle—splash half a ladle or one ladle of water each time, evenly over the hottest spots on the stones.

For a more relaxing social sauna, a leisurely, low-frequency rhythm is recommended, perhaps every 5-10 minutes. This way allows the heat from each splash to fully dissipate before adding more water when the room temperature dips slightly. For a high-humidity and high-temperature environment, splash more frequently.

Conclusion

If you seek the ritual of a traditional sauna and enjoy the pleasure of starting a fire, a wood-fired sauna stove is perfect for you. As an industry-leading sauna manufacturer, Alphasauna includes a wood sauna stove with every wood-fired sauna cabin purchase, though you may also buy one separately. This stove is manufactured by a major factory in China, ensuring its quality. Feel free to contact us!

FAQs

Question1: Are wood-fired sauna stoves a high safety risk?

Answer: Any open flame appliance carries potential risks, but they can be very safe through key precautions and proper operation. These include:
1. Ensure the installation complies with safety requirements and local codes.
2. Ensure adequate ventilation and fire protection measures.
3. Regularly clean and inspect.

Question2: Why is my wood-fired stove so hard to light?

Answer: There are many reasons for this phenomenon, such as a blocked chimney, a lack of airflow, or damp firewood. Solutions:
1. Clean the chimney.
2. Check that the chimney system and ventilation system are unobstructed.
3. Use dry wood.

Question3: Which is better, a wood-fired sauna stove or an electric sauna stove?

Answer: It all depends on your personal needs and preferences. There’s no better option—only the more suitable one. If you desire an authentic sauna experience and don’t mind the extra waiting time and cleaning work, then choose a wood-fired sauna stove. If you use your sauna frequently and don’t have much time for the extra work, then an electric sauna heater is clearly the better choice for you.

Question4: Does the wood-fired sauna stove use paint? Is it safe?

Answer: The stove body is coated with high-temperature resistant powder coating, which is durable and protects the metal from oxidation and rusting at high temperatures.

Question5: When using a wood stove for the first time, there is a small amount of smoke leakage. Is this normal?

Answer: A small amount of smoke leakage may occur during the first use of your wood stove. This is completely normal, so please don’t worry. This is because the high-temperature powder coating inside the firebox needs to cure when it’s first exposed to heat. This generally disappears after about 40 minutes of preheating.