Near vs Far Infrared [2021 Guide]
Surface temperature dictates wavelength
Written by Christopher Kiggins
The Importance of Surface Temperature The Importance of Surface Temperature
The surface temperature of the heater is going to determine the infrared wavelength that is absorbed into your body. The longer the wave, the more that can be absorbed. As discussed in previous chapters, How Infrared Saunas Work, Wien’s Law shows the thermal energy output in microns. As a result of inputting a surface temperature, you get a wavelength that shows how deep a heater can penetrate into your body with far infrared waves.
So what’s the best micron wavelength for your body to absorb in an infrared sauna? What will provide the maximum health benefits?
The short answer is 7.90 microns.
Now I’ll show you how we got there.
The most important factor for receiving health benefits in an infrared sauna is raising your core body temperature. As a result, your body will excrete toxins, you will lose weight and recycle old cells, so you must have a sauna that gets hot. The best surface temperature to heat your body and penetrate deep into your tissue is 200 °F.
5268 / (200 °F + 460) = 7.90 microns
As we see in the infrared light chart, the far infrared spectrum of light goes from 4 to 1000 microns.
Remember that the Wien’s Law formula is actually an inverse of surface temperature to wavelength. The hotter the surface of an object, the shorter the wavelength. The inverse is true as well. As we get a higher micron level, the surface temperature drops and the wavelength becomes longer.
Near-infrared is represented in the infrared spectrum from .7 microns to 2.0 microns. Using Wien’s Law, this results in a surface temperature of 2150 °F – 7000 °F. The interior air temperature will obviously never get that hot in any infrared sauna, but in order to mathematically get the proper near-infrared wavelength, the near infra-red heater must (theoretically) get that hot.
The problem, besides the unreasonable heat requirement, is that the lower micron level does not help you attain the major health goals of infrared saunas—rest, weight loss and detoxification.
Near Infrared Near Infrared
Near-infrared heaters operate at a much higher temperature than far infrared heaters. The hottest a far infrared heater will get to is 825 degrees °F. At a 4.0 micron wavelength, the surface temperature of the infrared heater is 825 degrees °F, which is highly uncomfortable to be sitting a few inches away from.
As I explained earlier, by trying to produce a deep sweat using the near-infrared band of radiant light, you have to heat the surface temperature of the object producing heat to at least 2,150°F. Shall I repeat that?
Now, there is an entire sub-section of infrared saunas out there called “near infrared saunas.” You might have heard of them. They claim to use near infrared heaters alone to heat your body. However, having done our research and scientifically proven that no infrared sauna heater has the surface temperature hot enough to be in the near infrared bandwidth, these claims are false!
“Near infrared sauna” are using far infrared heaters! You can tell as they use halogen heaters! Simply return to the previous chapter explaining halogen heaters. However, these heaters are still extremely hot at 775°F.
Because these “near-infrared sauna” heaters are so hot, there is usually only one side of the body being heated at a time. Take a look at the following pictures:
The “near infrared” lamps only exist from one location in the sauna—there aren’t multiple panels. If there were panels on both sides, you would heat yourself to unsafe levels. Because there is only one direction the near infrared light is coming from, you have to continuously turn your body like a rotisserie chicken to produce a full body sweat. This is far from the even, enveloping, 360° heat of a far infrared sauna.
The Bonfire Explanation The Bonfire Explanation
The thermal radiation created by a bonfire travels away in all directions. Heat that is transferred via convection mostly travels upwards as the heated air billows up. If you are to the side of the fire, the heat you receive is transferred via thermal radiation (i.e. infrared light).
If you are standing directly above the fire, you receive heat from both thermal radiation and convection (not a good place, mind you). For this reason, directly above the fire is the hottest place to be.
Note that thermal radiation can include many different wavelengths of electromagnetic radiation and not just infrared. So what’s the internal temperature of a bonfire? 2100-2200°F!
These are actual near infrared temperatures!
So, here’s a great way to explain how near infrared doesn’t actually exist in an infrared sauna:
As we’ve already shown, “near infrared heaters” don’t exist. They simply don’t have the surface temperature in the proper range 2150°F+ to be considered near infrared, let alone mid infrared!
But, let’s say for kicks that you did actually sit next to an object with the same internal temperature as a bonfire… Have you ever sat next to a roaring bonfire outside on a cool night? It feels amazing right? But why does it feel good? Because you’re sitting far enough away from it to be the right temperature for you to feel comfort in the warmth. You don’t sit directly next to the fire!
If you sat directly next to the fire your clothes would literally start burning from the heat of the air alone! So what do you do? Move away to a safe and comfortable distance.
My point being, that by the time the infrared waves hit your body from a bonfire operating at 2200°F, that thermal radiation (and respective infrared waves) have cooled significantly to be inside the far infrared bandwidth of light.
So, while you might be seeing a near infrared fire, you are feeling far infrared heat!
Far Infrared – The Game Changer Far Infrared – The Game Changer
Far infrared saunas actually became popular much earlier than near infrared saunas. When it was discovered you could skip a step by heating your body directly, instead of the air and water between (like traditional saunas), it was by using the far infrared wavelength.
The objective of an infrared sauna is to produce a deep and sustained sweat by whole body hyperthermia, and no more than that. In order to hit this exact measurement, you must heat the body by using an optimal wavelength of light (the Peak Emission Wavelength) that results from the thermal radiation of an object (the surface temperature).
Far infrared is fantastic for many of the same things that near infrared is great for—a boost in metabolic rate, reduce and burn fat cells, improved circulation, increasing cellular energy, faster skin rejuvenation, and faster cellular perfusion.
I am in no way saying that near infrared doesn’t have therapeutic value (as we’ll see in a later chapter); however, in the infrared sauna environment, it is less than ideal. If you are certain you need near infrared, I would recommend a handheld near-infrared LED light panel that you place directly on top of your skin outside of the sauna.
I highly encourage you to conduct as much research on near vs. far infrared as you’d like but remember to look for the science behind the claims. The purpose of using an infrared sauna is the cumulative health benefits, all of which can be safely and comfortably attained through far infrared while you are sweating, losing weight, and detoxifying your body.
Moreover, if you are sitting in an infrared sauna and it is producing heat, you’re sitting next to a far infrared heater, no matter what they tell you!
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I am glad infrared saunas have developed the way they have, because I couldn’t imagine my life without the benefits they provide, like deep sleep, lower blood pressure, less joint pain, weight loss, and a boosted immune system. Here at SaunaCloud I sell saunas that are some of the best history has offered. My far infrared saunas use advanced ceramic-carbon combination heaters for an amazing sauna experience. For more information on how SaunaCloud’s infrared saunas work and how they can improve your health, download my book The Definitive Guide to Infrared Saunas. Just give us a call at SaunaCloud 1.800.370.0820.
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