Since my last post I have found a little bit more information on FIR like
mine.

For information of any new members, I bought a Prime Infralite here in
Australia. I find this is the same as one sold in the US as Relax Sauna.
It has a reflective vinyl cover forming a tent-like cubicle. This had a
chemical smell at first, but this dissipated quite soon.
One advert stated that it would not absorb odours, but I do find that the
detox smell I believe to be my own is detectable in the room where the tent
is; if it is not on the walls, which I wiped, I wonder whether it is on the
zips, or the footmat, or the heaters. I do cover these with flannels before
putting my foot on any of these.

I have already reported that I find the air flow from the heaters
uncomfortably hot.
Sitting on the (very unsatisfactory) seat on towels always leaves me with a
cold behind. I tried an experiment to know how it would be if I wanted my
hindquarters FIR'd.

I stood on a towel in the middle of the tent with the zip
zipped up as close as it would go to my waist, and a towelling robe around
my top and waist. I did it for ten minutes then another five. (FIR unit
same as the one on http://www.momentum98.com/relaxsauna.html where they call
it the relax sauna).

Nothing sweated, but my legs got very red and I was dancing around like a
lizard in the desert trying to preserve my legs from the unbearable heat.
It was just too hot! I have put a thermometer inside now so I can measure
the heat next time. This is just too hot; with full reflective power I
guess I'm getting all the FIR radiation, but the hot air coming out of the
heaters is what is too hot. Sitting down, I am able to put my feet up on
top of the heaters to get them out of the hot blast, but standing, there was
not very much in the way of alternatives! I should probably try to have one
foot on top of one heater, then alternate.
Bit of exercise at the same time.

The behind did get warmed up, though.

I was rather intrigued that despite the temps and time (at least 15 min
total) there was no sweating. (Heat, of course, as I was standing, only
reached legs and hips.)

Last night I was reading more, and feel I have a slightly better
understanding of how they get the FIR to work. Please correct me if I've
got it wrong, but it sounds as if the "ordinary" heat from
the heating element (I suppose) is blown on to the FIR component and
activates it. I feel rather disappointed, rightly or wrongly, that this is
not "just" FIR but appears to depend on ordinary heaters too. I don't know
whether this uses more electricity than the oft-quoted sum of 10c per hour.

I did get more information from the site I visited which sells the Relax
sauna, and the pictures did show the component parts
http://www.momentum98.com/relaxsauna.html . I really would have expected to
be able to find a site by the manufacturers, but so far no success.
Probably China.

The article on http://www.backandbodysolutions.com/saunas.html was very
interesting. It is probably worth reading, no matter what you end up
buying. One part
said:
The most important question you can ask of the sauna company you are
considering is to provide independent proof of the micron output of their
saunas. Most will not publish these figures in their literature or their
internet site. (If you can even find their internet site! - R) Saunas that
use rod heaters typically run at 400 to 600
degrees and have low micron output. Saunas that use ceramic or aluminum
plates or carbon panels run at a lower temperature and have the proper
output.

All saunas will make you sweat but will not release toxins from the water
molecules effectively unless their peak output is in the 9 to 10 micron
range. This is a fact of physics and physiology no matter what their
marketing hype says. We know for a fact that one of the oldest and largest
manufacturer of saunas has been using heaters that only go up to 5.5
microns. For more information in this area, go to www.tempco.com

and

The efficiency of converting electricity to heat is another factor to
consider. Some sauna companies make saunas with a lower efficiency,
therefore, their larger models require 220 volt power. This may require an
expensive electrical installation and a higher electrical bill. Another
reality is that all saunas, no matter what brand, take about the same time
to heat up and cost about the same to run, about ten cents per hour
depending on your local electrical costs. One company advertises a large
carbon panel in the back wall that heats up in two minutes - we tested it
and while the panel does get hot in two minutes, it still took 20 minutes
for the whole sauna to heat to 110 degrees.
(I will test this on mine now that I have put a thermometer in there, though
being metal the thermometer will probably burn me! No, OK, I'll hold it
with a flannel to read)

and

What we also found out is that many manufacturers put misleading and false
information in their literature and internet site or totally leave out
pertinent information. Without naming any specific manufacturer, we want to
educate you about the components of an infrared sauna so you will be able to
ask the right questions of the companies whose sauna you are considering.

While I would really like to understand the various FIR heaters' technology
and manufacturing methods, I am really just blundering around here. I did
look at tempco, but wasn't much wiser. I presume they supply the heater
that activates some company or other's FIR.

R