How to Clean Your Indoor Sauna

Complete Guide to Cleaning and Caring for Your Indoor Sauna

Keeping your indoor sauna clean is key to preserving its appearance, performance, and hygiene. Even though Canadian Hemlock is a premium timber known for its natural resistance to warping, mold, and decay, regular maintenance ensures it stays beautiful and functional for years.

After Each Use: Quick Hygiene Habits

To maintain freshness and prevent bacteria or mildew:

• Wipe down all contact surfaces (benches, backrests, walls) with a clean, damp cloth.
• Leave the door open for 10–15 minutes post-session to ventilate and allow excess moisture to escape.
• Sit on a towel during use to absorb sweat and body oils — this reduces staining and prolongs the cleanliness of your wood surfaces.

Why it matters: Repeated moisture and sweat exposure without cleaning encourages wood darkening, odour build-up, and even bacteria growth in untreated areas.

Weekly or Deep Cleaning: Keep the Wood Like New

At least once a week (or more often if used daily), perform a deeper clean:

1. Turn off the sauna and let it cool completely.
2. Sweep or vacuum the floor and corners to remove dust, hair, and debris.
3. Wipe surfaces with a soft sponge or cloth using warm water mixed with a small amount of mild, natural soap.
4. Avoid harsh cleaners or chemicals, as these can damage the timber and emit fumes when heated.

Don't use: Detergents, bleach, or abrasive scrubbers. These strip natural oils from the timber and can leave behind toxic residues.

Handling Stains, Sweat Marks & Discoloration

Notice dark patches or marks?

• Lightly sand affected areas with fine-grit sandpaper (always in the direction of the grain).
• This technique refreshes the surface and removes buildup without harming the wood.

Pro Tip: Sand sparingly. Over-sanding can thin the timber surface or cause uneven texture.

Mold & Mildew Prevention

Though rare in well-maintained saunas, mold can still form in high-humidity environments.

If it appears:

• Use a 50/50 solution of white vinegar and water on a cloth to wipe affected areas.
• Dry the wood thoroughly with a clean, dry towel.
• Never use bleach — it may off-gas toxic fumes when the sauna heats up.

Tip: Improve airflow between sessions. Leave vents open and ensure no water pools beneath floor slats.

Heater & Sauna Stones Maintenance

Maintaining your heater and stones is just as important:

1. Ensure the heater is off and fully cool.
2. Remove all stones and inspect them. Replace cracked or crumbling stones.
3. Wipe down the heater housing and vacuum around the base to remove dust or debris.
4. Re-stack the stones loosely, ensuring good airflow between them.

Refer to your Harvia heater guide for specific stacking instructions.

Long-Term Sauna Care Tips

• Inspect and tighten all screws, brackets, and hinges every few months.
• Never seal, paint, or varnish the interior. Canadian Hemlock is designed to “breathe.” Sealing it traps moisture, encouraging mold and warping.
• If your sauna is in a humid location, consider using a small dehumidifier outside the sauna to keep the ambient moisture levels down.

Need Assistance?

If you’re unsure about a cleaning product or how to handle specific damage, contact our support team — we’re here to help you get the most from your Nordhaus sauna.