How to Clean and Maintain Your Infrared Sauna: The Complete Guide from 3,000+ Installations

You're sweating heavily in an enclosed wooden space for 30–45 minutes, 4–5 times a week. Without proper care, that's a recipe for stained wood, odor buildup, and — in the worst case — mold. The good news: maintaining an infrared sauna is simple, takes minimal time, and — if your sauna is built with the right materials — requires nothing more than a towel, sandpaper, and water.

After twelve years and over 3,000 installations, I've seen every maintenance scenario. This guide covers exactly what to do — and what to never do — to keep your infrared sauna looking, smelling, and performing like new for decades.

Why your wood choice determines your maintenance burden

Before we get into the maintenance schedule, understand this: 80% of your maintenance burden is determined by the wood your sauna is made from. Western Red Cedar has natural properties that make maintenance dramatically easier than any other option.

Cedar's natural oils — thujaplicins — are genuinely antimicrobial. They inhibit the growth of bacteria, mold, and fungus without any chemical treatment. That pleasant cedar aroma you smell when you step into your sauna? That IS the antimicrobial agent at work. Cedar has been used for clothing chests, closets, and exterior applications for centuries specifically because it resists biological degradation.

Cheaper woods — hemlock, basswood, spruce — lack these natural defenses. They require chemical treatments to resist mold (which then off-gas in heat), they stain permanently from sweat, and they don't handle the repeated expand-contract cycle of heating and cooling as gracefully. Plywood-backed saunas are worst of all: moisture gets trapped behind panels, creating an invisible mold factory.

The maintenance schedule

After every session — 2 minutes

This is the single most important maintenance habit. It takes 2 minutes and prevents nearly all long-term issues:

• Wipe down benches and backrest with a clean, dry towel. Sweat left on wood absorbs into the grain within minutes, causing salt deposits and body oil stains. A quick wipe while the wood is still warm removes everything.
• Leave the door open for 15–20 minutes. This allows moisture and residual heat to escape, preventing a damp sealed environment. This single habit is the most effective anti-mold measure.
• Remove any wet towels — don't leave them on the bench or floor. Wet fabric in an enclosed space breeds bacteria overnight.
• Pro tip: Always sit on a dedicated sauna towel during your session. This catches most sweat before it ever touches the wood. Two towels — one under you, one behind your back — prevent virtually all wood staining.

Weekly cleaning — 10 minutes

• Wipe all surfaces with a damp cloth — warm water only. NO chemical cleaners, NO bleach, NO wood polish. Just water.
• Vacuum or sweep the floor to remove dust, hair, and skin cells.
• Dust heater panels with a dry cloth. Dust accumulation on VantaWave® heaters reduces infrared output efficiency.
• Clean the glass door with a damp cloth. Sweat spray creates a mineral film on glass over time.
• Light sanding if needed: If sweat stains have set into bench wood, use 220-grit sandpaper and lightly sand the stained area, following the grain. Cedar refreshes beautifully — the fresh wood underneath looks and smells like new.

Monthly deep clean — 20 minutes

Hydrogen peroxide spray: Mix 3% hydrogen peroxide with equal parts water in a spray bottle. Lightly mist bench and backrest surfaces, let sit for 2 minutes, then wipe clean. This is the only cleaning agent I recommend. Hydrogen peroxide is natural, breaks down into water and oxygen (no residue), and effectively kills bacteria. It does not off-gas at sauna temperatures.

Monthly sanding: Give bench and backrest surfaces a light pass with 220-grit sandpaper, following the wood grain. This takes 5 minutes and removes the accumulated surface layer of sweat staining, exposing fresh, clean cedar that looks and smells brand new. This is the "cedar refresh" technique — it works because solid cedar is the same wood all the way through. Plywood, veneered wood, and chemically treated surfaces can't do this.

Hardware check: Tighten any loose screws on benches or panels. Wood expands and contracts with each heat/cool cycle — screws can gradually work loose over months. A quick check prevents wobbly benches.

Quarterly maintenance — 30 minutes

• Deep sand: Give all bench surfaces a thorough sanding with 220-grit — the quarterly "reset" that keeps cedar looking premium for decades.
• Ventilation check: Ensure air vents aren't blocked by towels, mats, or debris.
• Door seal inspection: Check that the glass door gasket is intact and the door closes snugly.
• Control panel check: Verify the digital display functions correctly and temperature readings are accurate.
• Outdoor saunas: Inspect exterior seals, roof drainage, and the base for any signs of water intrusion. Check caulking around the door frame.

Dealing with specific issues

Sweat stains (dark spots on bench)

The most common issue. Sand with 220-grit following the grain, wipe clean with a damp cloth. The stain is only surface-deep — fresh cedar is immediately underneath. Prevention: always sit on a towel. This eliminates 95% of staining.

Musty or stale smell

Almost always caused by not leaving the door open after sessions. Resume the door-open habit and spray surfaces with hydrogen peroxide solution. Run a session at max temperature with the door cracked for extra ventilation. The cedar aroma should return within 1–2 sessions. If the musty smell persists, check for moisture behind panels — common in plywood saunas, extremely rare in solid cedar construction like SaunaCloud builds.

Mold (rare with cedar)

Mold on Western Red Cedar is extremely rare because cedar's thujaplicin oils are naturally antifungal. If you see mold: spray with 3% hydrogen peroxide, let sit 10 minutes, wipe clean, sand the area with 220-grit. Improve ventilation — leave the door open longer after sessions. If mold recurs, there's almost certainly a water intrusion or ventilation problem to diagnose, not a wood problem.

Minor cracking or checking in wood

Small surface cracks (checks) are normal with natural solid wood that goes through repeated heat/cool cycles. They're cosmetic, not structural. Cedar's tongue-and-groove construction accommodates expansion and contraction. If a board develops a significant split, contact SaunaCloud support at 800-370-0820.

What NOT to do — common mistakes that damage saunas

• Don’t use chemical cleaners: Bleach, Lysol, Pine-Sol, and all-purpose cleaners leave chemical residue that off-gasses at 130–145°F. You’re inhaling those fumes during your session. This directly contradicts the zero-toxin philosophy of a quality infrared sauna.
• Don’t stain or seal the wood: No polyurethane, no tung oil, no wood stain. These coatings trap the natural oils that make cedar antimicrobial, and they off-gas toxic VOCs when heated. Cedar is designed to be bare. Coating it is like putting a raincoat on a fish.
• Don’t apply essential oils directly to wood: They stain the cedar and the residue is very difficult to remove. If you want aromatherapy, use a diffuser placed outside the sauna or in the ventilation pathway.
• Don’t pressure wash the interior: Saturating the wood with water can damage heater components and electrical connections. A damp cloth is all you need.
• Don’t leave the sauna sealed after sessions: Especially in humid climates. Moisture needs to escape. Door open, 15–20 minutes, every single time.
• Don’t panic about dark stains: Sweat stains on cedar are cosmetic, not structural. A 30-second sanding removes them completely. They’re the most common “problem” that isn’t actually a problem.

Every one of these mistakes is something I’ve seen in the field — usually from well-meaning owners who applied cleaning habits from their kitchen to their sauna. Your sauna is not a countertop. It’s a therapeutic space made of living wood that’s heated to 140°F while you breathe inside it. The cleaning rules are different because the stakes are different.

How long your sauna lasts

With the maintenance schedule above, a well-built infrared sauna is a multi-decade investment:

• Cedar structure: 25–50+ years. Western Red Cedar is used for exterior siding, roofing shingles, and marine applications precisely because of its longevity.
• VantaWave® heaters: 20,000+ hour lifespan. No bulbs to replace, no elements to change, no maintenance required.
• Control panel / electronics: 10–15 years, field-replaceable without rebuilding the sauna.
• Glass door: Tempered glass doesn't degrade. Lifetime component.
• Comparison: Mass-produced prefab saunas with hemlock and plywood typically show significant degradation at 5–8 years — warping, delamination, mold behind panels, and heater failure.

The investment math: a SaunaCloud sauna that lasts 30 years costs less per year than a cheap sauna you replace every 6 years — and it looks and performs better every single one of those years. For more on our construction philosophy, visit how we build or browse the complete guides library.

Frequently asked questions