# Home Sauna, Steam Room and Cold Plunge Maintenance

How to clean sauna wood, look after heater stones, flush and descale a steam generator, and keep cold plunge water clean, based on manufacturer care pages and manuals.

Updated 2026-10-29. Also on the [web page](https://privatewellnessrooms.fyi/guides/home-sauna-steam-room-and-cold-plunge-maintenance).

A wellness room has three systems that need different care: sauna wood and heater, steam generator, and plunge water. This guide collects what manufacturers tell owners to do. Always follow the manual for your exact model first.

## Sauna wood

Finnleo gives these routine care rules:

- Do not paint, varnish or stain the interior surfaces. The wood must breathe.
- After each use, scrub the benches, walls and backrests with a hand brush and plain water. Finnleo says this takes 30 to 60 seconds.
- Lift the duckboards off the floor. Leave the door open so the room dries fully.
- Remove sweat stains with a hand brush and warm water with a mild detergent.
- Lightly sand the benches about once per year to bring back their original color.

Harvia's Spirit heater manual adds a deeper cycle. Wash the room at least every six months with a scrubbing brush and sauna cleanser, then rinse. Harvia also recommends seat towels. It says wood that goes darker over time is normal.

## Heater and stones

Stones break down slowly because of large changes in temperature. Harvia's guidance:

| Task | When | Source |
|---|---|---|
| Rearrange stones and remove debris | At least once a year, more often with frequent use | Harvia stones page |
| Replace stones that crack or sound shallow when tapped | When you rearrange | Harvia stones page |
| Remove lime stains from the heater with a 10% citric acid solution | As needed | Harvia Spirit manual |
| Wipe dust off the heater with a damp cloth | As needed | Harvia Spirit manual |

The Spirit manual allows only stones 5 to 10 cm across, in peridotite, olivine diabase or olivine. Use only clean tap water on the stones. Pool or spa water can release chlorine gas.

## Steam room and generator

Minerals in the water collect inside the generator tank.

**Thermasol** has a self-cleaning cycle, PowerFlush, that removes sediment and mineral build-up. It also recommends a manual descale by a licensed plumber or authorized technician every few years. For the room, it advises non-abrasive, pH-balanced cleaners, because harsh chemicals can etch natural stone. For the drain, it suggests boiling water, then a 1:1 mix of baking soda and vinegar, then more hot water.

**Mr. Steam** tells owners to open the manual drain valve fully every 2 months, or more often in hard water areas. Let the water cool first. Its optional AutoFlush system drains the generator after each use, after about two hours. The manual recommends feedwater hardness of 8 to 85 ppm.

## Cold plunge water

| Brand | Water treatment stated | Water change | Filter |
|---|---|---|---|
| Renu Therapy | Ozone and filtration, no chemicals for home use | Every 4 to 6 months | Cold Stoic 3.0 and Aurelius: primary filter every 2 to 4 weeks |
| Ice Barrel | Optional water stabilizer | Every four weeks, or as preferred | Not stated |
| Morozko Forge | Microfiltration and ozone | Not stated on the page we fetched | Not stated |

Renu says lotions, sunscreen, oils and sweat clog filters faster. Keep the lid on and rinse off before you get in.

## A simple schedule

- **After each session:** brush and air the sauna, rinse the steam room and let it dry fully, close the plunge lid.
- **Every few weeks:** check or change the plunge filter.
- **Every 2 months:** drain a Mr. Steam generator without AutoFlush.
- **Every six months:** wash the sauna thoroughly.
- **Every year:** rearrange or replace heater stones and lightly sand benches.
- **Every few years:** have a professional descale the steam generator.

To find installers and service firms near you, compare builders, dealers and installers in the directory.

## Sources

- [Finnleo: Sauna Care and Maintenance](https://www.finnleo.com/sauna-maintenance) (fetched 2026-10-29)
- [Harvia: Sauna heater stones](https://www.harvia.com/en/sauna-heater-stones/) (fetched 2026-10-29)
- [Harvia Spirit Owner's/Operator's Manual (PDF, hosted by Saunaplace)](https://resources.saunaplace.com/pdfs/Harvia-Spirit-IOM.pdf) (fetched 2026-10-29)
- [Thermasol: 5 Tips to Keep Your Steam Shower Clean and Performing at Its Best](https://www.thermasol.com/blogs/wellness-rituals/steam-shower-cleaning-tips) (published 2024-05-15)
- [Mr. Steam: Installation, Operation and Maintenance Manual, residential models MS90E to MS400E (PDF)](https://pim.mrsteam.com/Resources/Entities/Mrsteam/Documents/6446cb4f-5f9a-433c-9c0a-111dab242cb3.pdf) (fetched 2026-10-29)
- [Renu Therapy: Cold Plunge and Sauna FAQ](https://renutherapy.com/pages/faq) (fetched 2026-10-29)
- [Ice Barrel: FAQ](https://icebarrel.com/pages/faq) (fetched 2026-10-29)
- [Morozko Forge home page](https://morozkoforge.com/) (fetched 2026-10-29)

## Questions

### How often should I replace sauna heater stones?

Harvia advises you to rearrange the stones at least once a year, or more often with frequent use. Replace stones that crack or sound shallow when you tap them together.

### Do I need to descale a steam generator?

Yes. Thermasol recommends a manual descale by a licensed plumber or authorized technician every few years. Mr. Steam tells owners to drain the generator every 2 months, or more often in hard water areas.

### How often should I change cold plunge water?

It depends on the product. Renu Therapy says every 4 to 6 months. Ice Barrel recommends every four weeks.