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One of the most fundamental aspects of an infrared heater is the
wattage. As we covered in our last section about types of infrared,
wattage in conjunction with surface area are the primary factors
in determining the temperature of an infrared heater's surface.
This
is important
because the
lower
the surface temperature, the longer the far infrared. In
that same
section about types of infrared, we used Wien's law to approximate
a micron range from the temperature of the heater and found that
lower temperatures produce longer wavelengths. The final result:
lower wattages result in longer wavelengths.
ALL ABOUT WATTAGE
A good rule
of thumb is that on average, a pure ceramic heater heater over
250 to 300 watts is going to produce mostly medium
to short
wave
infrared
(0.076 - 5.8 microns). While many companies do not provide you
with
the wattages of their individual infrared heaters, you can do a
little math to get an average wattage of the heaters based on
the
the number of elements and total power of the unit. For example:
Example Unit power 1700w with 5 heaters: 1700/5
= 340w average
While this analysis certainly applies to all infrared heater types,
it is especially relevant to a discussion of ceramic heaters, as
there are a number of ceramic heaters on the market with exceptionally
high wattages.
INFRARED HEATER EMMISSIVITY DIFFERENCES
Materials with varying emissivity have different capacities to
emit far infrared. The higher the emissivity, the more efficient
that surface is going to be at emitting infrared heat. A surface
such as aluminum will have an emissivity range of .1 to .6 (10%-60%),
while ceramic has an emissivity of .85 to .95 (85%-95%), and carbon
has an emissivity range of .7 to .9 (70%-90%). The emissivity of
different materials, including those listed above, can be found
at this site. As you can see, the highest emissivity among these
materials is ceramic.
DOES SIZE OF THE INFRARED HEATER MATTER?
While the surface area of the heater is important, our research
has shown that physical size does the dispersion of the far infrared.
The problem with the discussion about heater
size (surface area) is that it too often gets used as a marketing
tool used to exaggerate the effectiveness of the infrared heater.
This study and others have convinced us of the opposite: that a
variety of wavelengths is most beneficial. This is in part because
heaters that emit MEDIUM Wave infrared heat between 1.5 –5.8
microns stimulate the body's warmth-sensing nerves to produce the
most sweat. Longer far infrared heat waves are potentially better
at penetrating deeper inside the body tissues. It is our experience
that a combination of different infrared wave lengths will produce
the best overall results. That's why we believe that the variety
of different wavelengths provided by the heaters within an infrared
sauna is more important than the heater size itself.
INFRARED HEATER TYPES
Ceramic-The American Society for Testing and Materials
(ASTM) defines a ceramic article as “an article having a glazed
or unglazed body of crystalline or partly crystalline structure,
or of glass, who's body is produced from essentially inorganic,
non-metallic substances and either is formed from a molten mass
which solidifies on cooling, or is formed and simultaneously or
subsequently matured by the action of the heat.”
CERAMIC HEATERS (CYLINDER)
Cylinder ceramic heaters are used by a number
of different infrared sauna companies because they are extremely
efficient at radiating infrared heat, and they have a high emissivity
rating, making them more energy efficient for use in infrared
saunas.
Benefits of Cylinder Heaters: The cylindrical
shape allows the heater to project most of its energy towards
the user,
and the infrared waves that come off the backside of the cylinder
are reflected back towards the user, and away from the wall of
the
infrared sauna by polished stainless steel concave reflectors.
One drawback of the cylinder type is that due
to the smaller size of the heater, they are often times overpowered
with high wattages.
CERAMIC HEATERS (CONCAVE)
Concave ceramic heaters are offered by a few infrared
sauna companies, and are able to spread infrared heat very well.
Unfortunately, in many cases these heaters have small galvanized
metal casings that do not provide much reflection of the heat waves
emitting from the back of the heater source.
While it does not necessarily make them an ineffective heater, it
does make them much less efficient.
CARBON HEATERS (FIBERGLASS)
Carbon heat panels start as a piece of flexible
fiberglass, which is made of epoxy resins and glass. A very thin
layer of carbon is printed onto the fiberglass, and another fiberglass
layer is added to encase the layer of carbon into the middle. Then
the entire fiberglass panel is pressure laminated.
Benefits of carbon style heaters include that
many people believe that they have a sleek look, especially when
they line the walls of the sauna. They also have a large surface
area, which can help to reduce the surface temperature,
though not as extensively as reducing the overall wattage of the
heater.
Drawbacks of the carbon heater has to do with
the fundamental property of infrared waves in general. An infrared
wave will only travel perpendicular from it's surface. Therefore,
by having a flat heater surface, the infrared waves can only travel
straight out from that surface. What this effectively means is
that unless you are sitting directly in front of a heater you
are not
being directly exposed to the beneficial infrared waves.
No long term research on the effects of these heaters on
humans have been performed.
Materials in carbon heaters are numerous. These
heaters are often branded as "organic carbon heaters" by
infrared sauna companies that use and sell them, but this claim
does raise some questions:
Components of “Carbon” as published in advertising
for at least one company promoting Carbon heaters:
Fiberglass Cloth: SiO2, PbO, Al203+Fe203/15%,
CaO+MgO/21%, NaO+K20/1%, B203+BaO/10%
Carbon Black: C, SiO2, PbO, Fe203 + Al203, Cao,
MgO, ZnO
Element Names listed above: Silicon, Carbon, Lead, Iron, Aluminum,
Calcium, Magnesium, Zinc, Sodium, Potassium, Boron and Barium.
With so many processed chemicals used in the creation of the carbon,
not to mention the resins used in the creation of the fiberglass
that surrounds the carbon layer, we would suggest caution when
analyzing
claims about "organic" carbon heaters.
At least one company boasts test
results displaying a graph that shows their heaters producing
a 9.2 micron wavelength. Upon comparison to the graph produced
from the actual study, we found it indicated the surface temperature
of the heater at significantly lower operating temperatures than
the actual heater used in the
their sauna. It is very important to carefully review any information
presented as
factual
data.
INCOLOY ROD HEATERS
Incoloy heaters look a lot like the metal heating
elements in electric kitchen ovens, only inserted into an infrared
sauna. They are a highly processed heater, and studies report them
to emit only 50-60% of their heat energy in far infrared form. Because
they are not as efficient at radiating infrared heat, much of the
heat coming off of these elements is of relatively low micron count
(or shorter wavelength) and does not offer as much therapeutic deep
penetrating far infrared heat.
Note: These types of heating elements are commonly
used in rock sauna heaters where a high air temperature is desired.
While shorter wavelengths heat the air better, they are not as effective
at heating the body.
ALUMINUM HEATERS
Aluminum heaters are typically made by encasing
incoloy heater rods inside aluminum sheets, which are then sprayed
on the front side with a thin spray paint coating which contains
less than 1% ceramic, according to tests. This allows infrared
sauna
companies to make heaters larger, yet there is considerable debate
about these infrared sauna companies calling them "pure ceramic"
heat sources for infrared saunas.
Drawback: A significant amount of the
energy being put into the heater is lost to the back of the sauna
walls, making these types heaters much less efficient for infrared
saunas than other types.
WHAT'S NEXT?
Now that you've learned about the different types of heaters, it's
time to talk a little bit about the different ways that they're
used. Click here to learn about the difference between constant
heat and thermostat systems.
PLEASE NOTE: The information in
this infrared sauna guide is free to print and distribute as long
as it is not modified in any way. Any publishing of this information
on the Internet does require a link placed back to this site.
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