Don't get caught in this trap. Unless you live on the top of Mt. Everest you are already exposed to considerable emf's just from being in the modern world.
FIR saunas are really good, high emf or not. You only spend 1/2 hour in there and the benefits will outweigh any perceived negatives at this point.
Keep hydrated with electrolyte drinks and start slow with the saunas.
People with emf sensitivities are probably metal poisoned, and FIR (Far-Infrared-Sauna)
saunas get metals out.
Don't ever go by reviews when selecting treatments: always test things out for yourself with direct experience. You can go to one of those tanning/beauty places to try one out once or twice before purchase.