Look for saunas with far-infrared heat if you can only pick one type. Cheap models use plastic frames that won't handle heat well; better ones hide metal-fiber structures underneath. Two infrared generators heat your body faster and hotter than one.
Let's say you are gonna pay the money and install a sauna or something. If you can get one that has a spectrum of near and far infrared, that can be very, very useful. If you had just to choose one and you really wanna heat up, then the far infrared units are probably better. If you look at a portable unit, please look at the way it's made. They look sort of like an old Russian steam sauna. Your head goes out the top. So there's some sort of a tent with a frame on the inside. Many of the cheaper ones are actually made of plastic and some other stuff that you might not wanna be heating up. The ones that we have used with folks have metal fibers. They look plastic to insulate, but it's actually mostly metal fiber. Then the other thing is on the inside, the infrared generating units. Some of the portable ones have one unit and some have 2. Our experience in doing internal temperature monitoring with patients is that if you have 2 generators, you're going to heat the body up much more quickly and to a higher level.
