What is a low EMF sauna, and do the numbers mean anything?

Keep reading: the details ↓

What is being measured

Anything with electric current running through it makes electric and magnetic fields. In a sauna, the number buyers see is almost always the magnetic field at mains power frequency (60 Hz in the US), sometimes called ELF, for extremely low frequency. It is measured in gauss, and for household levels in milligauss: 1 microtesla equals 10 mG.

For scale, the World Health Organization puts the average magnetic field inside North American homes at about 0.11 microtesla, roughly 1 mG. Right next to some appliances it can reach a few hundred microtesla.

Why distance changes everything

Magnetic fields from appliances fall off very quickly with distance. Wisconsin's health department gives the example of an electric can opener at about 600 mG at 6 inches and about 2 mG at 4 feet. NIOSH notes that fields often drop off dramatically within about 3 feet of the source.

Sauna numbers show the same thing. Sun Home's lab summary for its heaters (Vitatech Electromagnetics, January 2025) reports roughly 0.6 to 4.0 mG at 1 foot and 0.3 to 0.9 mG at 3 feet. Same heater, same lab, a several-fold difference depending on where the meter sat. So a maker quoting "under 1 mG on the heater surface" and another quoting "0.5 mG at the seat" are not telling you the same kind of thing.

Is there a standard?

We found none for saunas.

• The US government has not set exposure standards for public power-frequency fields, according to utility guidance that summarizes federal policy, and NIOSH says no federal limits for workers have been set either.
• International guidelines (ICNIRP) set a general public reference level of 100 microtesla, or 1,000 mG, for 50 Hz fields. Sauna marketing numbers sit far below that.
• The "3 mG" figure appears on many sauna sites, sometimes credited to the CDC. We could not find any CDC or NIOSH limit at 3 mG. The closest number we found is in the childhood leukemia studies WHO describes: a weak association with average home exposure above 0.3 to 0.4 microtesla (3 to 4 mG), measured around the clock, which WHO does not consider strong enough to show cause. It is a study finding, not a safety limit, and a sauna session is short.

WHO's summary also says evidence linking these fields to other health problems is much weaker. In plain terms: there is no established health threshold that a sauna under 3 mG passes and one at 5 mG fails.

What to ask before you trust a number

1. What was measured? Magnetic field in milligauss, not electric field, and not radio frequency.
2. At what distance? At the heater surface, or where you sit?
3. Who measured it? An independent lab with a named report, or the maker?
4. How? With the heaters running at full temperature, and whether the figure is an average (RMS) or a peak.
5. Can I see the report? A summary is not a report.

Safety listings such as ETL or UL are about electrical and fire safety. They are not proof of a particular EMF level.

The saunas we rate

• Sun Home Luminar 2-Person Outdoor Meets the Standard
  The clearest data we have seen: 0.5 mG, measured by Vitatech Electromagnetics, report available from Sun Home on request. Our rating.
• Clearlight Sanctuary 1 Editor's Pick and Sanctuary 2 Meets the Standard
  Clearlight states under 1 mG measured directly on the heater. Its pages say the shielding is independently tested but do not name the lab or publish results. Ask for the report. Sanctuary 1 rating, Sanctuary 2 rating.
• Dynamic Veneto Elite (Costco) Held and Dynamic Tuscany Elite (Costco) Does not meet
  Popular cheaper models we rate as benchmarks. Ask the maker for the distance and the lab behind any EMF figure. Veneto Elite rating, Tuscany Elite rating.

When we quote an EMF figure in a rating, we say who measured it and at what distance. See the TMR Standard.

Questions people ask