Sauna maintenance is mostly wiping, drying and a few annual checks, but the right routine depends on what you own. A cedar traditional room, an infrared cabin, a wood-burning stove and a backyard barrel each have different weak spots. I haven't serviced any of these myself, so this page collects what makers and a few retailers publish and shows where they contradict each other.
What this page adds
Every instruction here carries a source number, and where makers disagree (oiling the wood, bleach, pressure washing) I say so and tell you which advice I'd follow. Intervals are in one table at the end. Anything electrical beyond dusting goes to a licensed electrician, and I don't cover repairs.
How to clean a sauna: benches and walls
Use towels so sweat stays out of the wood, and leave the door open after a session so the room dries. HUUM adds that you should wash benches and floor with warm water and rinse off skincare residue such as scrubs or masks. Finnleo suggests scrubbing benches and walls with a plain-water hand brush for 30 to 60 seconds after use.
For periodic cleaning, the intervals differ. HUUM says heavily used saunas get a scrub with sauna cleaner every 6 months. FinnStyle says monthly with mild soap and water and a deeper clean every 6 to 12 months, scrubbing along the grain with a damp, not dripping, brush. Sun Home suggests a deeper clean every 2 to 4 weeks, depending on use. I'd start at monthly if the sauna is used weekly, and stretch it only if the wood still looks and smells clean.
Sweat stains: Finnleo says lightly sand benches about once a year, HUUM warns that sanding only worn spots leaves visible marks, and Sun Home calls sanding rarely needed.
What not to use on sauna wood
The lists overlap, with one important split. Sun Home says avoid bleach, ammonia, household cleaners (which it says can damage wood and give off fumes when heated), pressure washing and soaking. FinnStyle's list adds household disinfectants, steam cleaners, abrasive pads, furniture polish and wax, and says harsh chemicals can soak into wood and release fumes when the room heats up. Saunafin says disinfecting isn't needed because the heat deals with germs.
Finnleo goes the other way: it suggests Lysol or Pine-Sol on floors and warm water with bleach on duckboard mold. I'd keep chemical cleaners off anything you sit on, and if you use a stronger product on a duckboard, take it outside, rinse it and dry it fully.
Oiling and sealing wood: the makers disagree
- Finnleo says don't paint, varnish or stain interior wood because it must breathe, and treats paraffin oil on benches and walls as optional.
- HUUM says refresh protection every 1 to 3 years with paraffin or linseed oil on benches, wipe off the excess, and don't put sauna lacquer on bench boards.
- Saunafin says not to apply stains, oils or other treatments to interior wood.
- Sun Home lists oil-based products among things to avoid, saying they can trap heat or create odors. FinnStyle lists furniture polish and wax.
- Nootka calls water marks from sweat and steam harmless and cosmetic, and offers an optional water-based, non-off-gassing sealant from Homecraft Saunas for people who want to prevent them.
- One infrared maker's support page says to oil every 2 to 3 years with fragrance-free, sauna-specific oil, wipe off the excess, let it dry 48 hours, and run two empty heating cycles before use.
What I'd do with that: leave the interior bare unless the maker of my own sauna tells me to oil it, because bare wood is the only option nobody warns against. If you do oil, use only a product labeled for sauna interiors, and heed the point that unsuitable oils can release fumes.
Stones and heater care
For an electric heater, the stones do real work. Harvia says to check them at least once a year, remove all stones, tap two together, and discard any that crumble or are discolored, because grit from broken stones can damage the heater. Its support page says stones need replacing about once a year when the heater runs twice a week on average, and that they pack down over time, which reduces airflow and shortens element life. HUUM gives a usage-based version: check yearly or after 300 hours of heating, and replace crumbled or noticeably lighter stones, with replacing them all at once being the easiest route.
On mineral buildup, Harvia says to look for discoloration or limescale on the heater elements or frame, and if you see it, to consider replacing the heater and confirm it's being used per its instructions. HUUM says to use a sauna cleaning product on limescale from sauna water and to avoid abrasive pastes or rough sponges on stainless steel. Wash stones you keep with water and a soft brush, and let them dry before restacking. Let everything cool first. FinnStyle puts it bluntly: never clean a hot, steamy sauna.
If the elements don't heat, HUUM says to inspect and replace broken ones; I'd leave that and any wiring to an electrician.
Wood-burning stoves
A stove adds ash and chimney work. Harvia's schedule is ash pan after every use, air controls and exterior every 6 months, stones and chimney annually, with a professional sweep for heavy creosote or blockages. HUUM likewise says to empty the ash drawer before every session and have a specialist clean the chimney yearly. If you're comparing stoves, see my wood-burning sauna picks, and for how a traditional room works, the traditional sauna guide.
Infrared sauna cleaning: wood, glass and emitters
Infrared cabins have no stones, which makes them easier, but the panels are the part you must not treat like wood.
For the wood, one maker's support page says wipe with a dry microfiber cloth, remove sweat with a slightly damp cloth and dry immediately, and leave the door open 30 minutes. Plunge says wipe the bench with a damp cloth after every session and use a towel or washable pad.
For glass, the two makers differ again. The first says to spray neutral glass cleaner or denatured alcohol onto the cloth, never onto the glass, and avoid abrasives, steel wool and pure alcohol. Plunge says any standard glass cleaner is fine outside, but inside use only a water-dampened cloth and avoid chemical glass cleaners. I'd use plain damp cloth inside the cabin, which satisfies both.
For the emitters, both say dry and gentle. Plunge says dust felt heater panels with a lint roller or a vacuum brush attachment, only when the unit is off and fully cooled. The other maker says wipe grilles dry, never wet them, never press on the panels or apply products, and that the grilles keep a 10 cm distance from the hot panels, so don't remove them. For which cabins are worth owning, see my infrared sauna picks.
Mold, moisture and ventilation
I couldn't find a maker page with a full mold procedure. FinnStyle and Sun Home stress airflow: open the door and vents, use minimal water, and let the room dry completely. Saunafin suggests checking an outdoor barrel for water seepage every 2 to 3 months. On bleach for mold, Finnleo allows it on duckboards and Sun Home says avoid it, so call the maker for anything beyond surface spots.
Outdoor sauna and barrel sauna maintenance
An outdoor unit adds weather. Nootka, for its cedar barrels, says to seal the exterior once a year with OSMO 410, including stave end grain, and to check the three stainless steel bands as seasons change, tightening slightly loose ones with a wrench. Saunafin says a transparent waterproofing stain can keep cedar's color on the outside, never inside, and to tighten the stave bands if the wood shrinks. A related Saunafin page says to use a UV-inhibitor stain on the outside only and to check the stones for cracks every 6 to 8 months.
On how often, a retailer, Haven of Heat, gives 2 to 5 years between exterior coats depending on climate and product, with water-based stain-and-seal at 2 to 3 years, and suggests a droplet test: if water soaks in rather than beading, the finish has worn through. That clashes with Nootka's yearly sealing, though the products differ, and Haven of Heat is a retailer, so I'd weight the barrel's own maker higher.
For models built to live outdoors, see my outdoor sauna roundup, and for running costs my sauna cost guide. Wash the exterior at low pressure; Sun Home warns against pressure washing the interior.
Maintenance schedule by sauna type
This table collects the intervals above. Where sources differ I show the range.
| Task | Interval | Applies to |
|---|---|---|
| Wipe benches, door open to dry | After every session | All |
| Scrub benches and walls | Monthly to every 6 months (sources differ) | Traditional |
| Check stones, tap and discard crumbled | At least yearly, or after 300 heating hours | Electric heater |
| Replace stones | About once a year at 2 uses a week | Electric heater |
| Ash pan | After every use | Wood-burning |
| Chimney and stones | Annually | Wood-burning |
| Dry-dust emitter grilles and panels | Weekly to every 6 months (makers differ) | Infrared |
| Check for water seepage | Every 2–3 months | Outdoor barrel |
| Seal exterior | Annually (Nootka) or every 2–5 years (retailer) | Outdoor |
Frequently asked questions
How often should I clean my sauna?
Wipe after every session and leave the door open. Deeper cleans range from every 2 to 4 weeks to monthly to every 6 months for heavy use. Pick the shorter end if you sweat a lot or share the room.
Can I use bleach or household cleaner in a sauna?
Sun Home and FinnStyle say no, citing damage to wood and fumes when heated. Finnleo suggests bleach for mold on duckboards. I'd avoid it on anything you sit on.
How often do sauna stones need replacing?
Harvia says about once a year at twice-weekly use. HUUM says check yearly or after 300 hours of heating and replace crumbled stones. Heavier use means sooner.
Should I oil or seal the inside of my sauna?
Makers disagree. Follow the manual for your sauna, and don't use exterior stains or conventional finishes inside.
What I would do
For sauna maintenance on a traditional room, I'd wipe and vent after every session, scrub monthly with a soft brush and plain warm water, and leave the wood unoiled unless my maker says otherwise. I'd put stones on a yearly check, tapping them together and replacing crumbled ones, and I'd call an electrician for anything beyond dusting. For infrared, I'd keep liquids away from the panels and use a damp cloth on glass. For a barrel, I'd follow its maker's sealing schedule and check the stave bands each season.