Portable Home Spas-for example a 2 Person Spa on the picture are from photo gallery at wccomfort
How infrared spas work? Very scientifically it sounds like the electromagnetic spectrum is divided into three segments by wavelength measured in microns (1/1,000,000 of a meter)

1. 0.76 to 1.5 microns = near infrared
2. 1.5 to 5.6 microns = middle infrared
3. 5.6 to 1000 microns = far infrared

in fact this invisible band of light warms people without warming the air between the source and the person. Far-infrared radiant (FIR) heat rays warm your body directly.
Radiant heat is also called infrared heat or infrared energy. Infrared heated saunas directly penetrate up to 45 mm inside the body thus impurities and toxins are pushed out by means of lower and more comfortable temperature, and it is one of the most important characteristics of far-infrared saunas.