Sauna Heater Maintenance: What to Check and When

Whether you're enjoying the gentle warmth of an electric sauna or the rustic charm of a wood-burning stove, regular maintenance of your sauna heater is key to both safety and performance. Many sauna users overlook the importance of inspecting their sauna equipment—especially the stones and heating elements—until something goes wrong. Here's what every sauna owner should know.

Annual Check-Up: A Must for Every Sauna Owner

At least once a year, it’s a good idea to get your sauna checked. Call in a certified chimney sweep to look over the chimney, flue connections, and the heater to make sure everything’s clean and safe. It’s not just about keeping things running smoothly—it’s also a safety thing.

While you're at it, take a few minutes to check the sauna stones and the heater itself. Any signs of wear, cracks, or overheating? Stones looking a bit rough or discolored? For electric heaters, it’s a great time to check the heating elements, too. And if you’re running a wood stove, take a peek inside the firebox to make sure everything still looks solid. If your sauna starts smoking back inside or if you notice poor ventilation, call a chimney sweep immediately.

Wood-Burning Heater? Here’s What to Keep an Eye On

Proper Stone Placement: Stones should be laid evenly in layers without forcing them between the stone grate and hearth. Avoid piling stones too high. 

Correct Wood Use: Only firewood should be used—both hardwoods and softwoods are suitable. The optimal firewood length is about 30 cm, with a moisture content between 10–15%.

Avoid Overheating: Super dry, fine wood burns too fast and hot, which can overheat the stove. With good firewood and proper use, there shouldn’t be any soot.

Uneven Heat: Temperatures in wood-burning stoves tend to be less stable, which can lead to localized overheating. In some cases, this may damage components or even weaken welds in the stove.

Got an Electric Sauna Heater? Do This Instead

Stone Coverage is Crucial: The heating elements should always be fully covered by stones. If parts of the glowing red metal element are exposed, it's time to rearrange or replace the stones.

Stable Heat, Less Risk: Unlike wood-burning stoves, electric heaters are less likely to overheat or warp metal parts—as long as the stones are properly placed and maintained.

Water Placement Matters: Never pour water directly onto the glowing heating elements. Instead, ladle water gently and evenly over the stones.

Less is More: Always use smaller amounts of water on an electric heater to avoid water reaching too deep into the heater and damaging internal components.

Sauna Stones: When to Rearrange and Replace

If your sauna isn’t heating as effectively as before, or it takes longer to warm up, that may be a sign the stones are worn out. Even with light home use, it’s smart to rearrange the stones once a year. If you notice they’ve settled, shifted, or left parts of the heating element exposed—especially in electric heaters—take a few minutes to reposition them. This helps keep airflow smooth and your heater working efficiently. Replace any that are cracked or crumbling.

Here’s the Takeaway

Sauna maintenance doesn’t have to be complicated, but it does need to be consistent. With regular yearly checks, thoughtful care of your stones, and a little attention to how and where you pour water, you’ll extend the life of your sauna heater—and get the most enjoyment from every session.

So, when was the last time you checked your sauna stones or called a chimney sweep? Maybe it’s time.