N504JB
Unfortunately, after nine years and countless thousands of hours researching this modality I have become completely convinced that there is only one manufacturer in North America (Europe is way ahead of in this matter) who employs emitters which have been demonstrated to penetrate to the to the reticular dermis--the deepest layer of the skin.
Without exception, despite the inaccuracy of their pseudo-scientific claims, American manufacturers employ emitters that produce Infrared-B and Infrared C-waves, neither of which penetrate as deeply into the skin as they would have consumers believe. Infrared C waves (i.e., "longwaves"), for example, only penetrate to the dermis and heat is dissapated as it descends by convection to the reticular dermis where fat cells can be found. Some warmth trickles down to the deeper layers of the skin but hardly enough to be therapeutic.
Given that sweating in itself has an important impact on the elimination of bodily waste and sitting in a confined space with an ambient temperature above 120 degrees can act as thermal stressor which causes the heart to work harder, there is something to be said for the therapeutic possibilities of these units.
The individual, however, who believes forking over a few hundred bucks for emitters will elicit the same gains as someone who digs deep for an equisitely designed Infrared cabin employing state of the art full-spectrum IFR emitters is deluding himself.
One can tell the time with a knock-off Rolex bought from a street vendor in China but if an individual needs precise performance, if he or she has a need for exqusite engineering, state-of-the-art design, and a timepiece that is manufactured to last for decades, you won't find that quality on the cheap.
The analogy relates to what is going on today with Infrared saunas in North America. Almost every American-manufactured sauna claimes to be the industry leader and standard bearer of unsurpassable quality.
They either know they're blowing smoke or they don't know the facts of radiant heating. Either way, thousands of consumers have been had.