Why Choose Infrared?
What is Infrared?
Infrared light is defined as electromagnetic radiation that has a wavelength just greater than that of the red end of the visible light spectrum. The light spectrum (also known as the electromagnetic spectrum) moves from the shortest light wavelengths on the left to the longest waves on the right. Let’s go through each portion of the spectrum (from the left to the right).
The most biologically damaging light waves are gamma rays, which are the shortest. Gamma rays are what bad guys use to vaporize people in comic books. They are created by the hottest, most energetic objects found few places in the universe, such as pulsars, neutron stars, supernovas, and areas around black holes (not great for saunas).
The next light waves on the spectrum are x-rays, and they are related to gamma rays in that they are also biologically hazardous. X-rays do have beneficial uses in controlled environments.
The next invisible light on the spectrum is ultraviolet light which accounts for about 10 percent of the light energy coming from the sun. This form of light is more likely to cause harm than healing when exposed for long periods of time.
Visible light is the next portion of the spectrum and allows for our sense of sight and color. Here is an image to show you just how little the visible spectrum of light makes up of all light (see the color strip towards the middle?)
The reason why humans see different colors is because objects either absorb or don’t absorb these different light wavelengths, or frequencies, bouncing and reflecting off objects. The reason why you can see a red apple is because the organic compounds of the apple absorb every color but red.
The last and longest wavelength (700 nanometers) visible to the human eye is red. After that, light is invisible to the human eye. This is where infrared light exists. “Infra-red” actually means “below red” as infra is the latin word for below.
Infrared light naturally comes from the sun. In fact, the sun’s energy consists of 50 percent infrared light at the level of Earth’s atmosphere. At ground level infrared energy accounts for 53 percent of light—we just can’t see it. But we feel it.
All types of light penetrate into objects, not just infrared. As this light is the right wavelength to produce heat, it will infiltrate an object and transfer its radiant energy. This energy is then absorbed by that object at the molecular level, causing the thermal motion of the object’s particles and electrons. In layman’s terms, the absorbed heat moves or charges the object’s molecules. As a result, the object’s core/internal temperature will increase based on the level of absorption of infrared heat.
Just as certain objects absorb different colors, as in our red apple example, objects have different organic properties which allow them to absorb different levels of infrared!
We understand heat as humans either from thermal radiation (infrared light), an object emitting heat into the air (convection) or by touching an object directly (conduction). Most of the time when you feel heat, you feel infrared. Almost all thermal radiation consists of infrared wavelengths, which means that all objects that emit heat also emit infrared.
This is my favorite example:
When you are walking outside on a hot summer day past a brick building in direct sunlight, if you put your hand a few inches away from the bricks but you don’t touch them, you still feel the radiant heat coming off of the brick—that’s infrared! The sun’s infrared light has actually heated the ceramic bricks from the inside (through absorption) and then the heat is released in the form of infrared light. You experience this light as heat. This is how infrared night vision works—It’s picking up on your radiant infrared energy.
How does infrared work in a sauna?
Now that you understand what infrared light is, we can discuss how we harness it in the sauna environment.
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 due to your body’s resonant frequency. We’ll get into why below.
There is a scientific principle that will give you the wavelength of infrared from a given object’s surface temperature called Wein’s law of displacement. Here is the formula:
5268 / ( temperature °F + 460) = the Peak Emission Wavelength (PEW) of an object (measured in microns)
PEW is the wavelength of infrared light that is measured in microns.
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. The best surface temperature to heat your body and penetrate deep into your tissue is 200 °F. Here’s why:
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.
It’s important to note that Wien’s Law formula is actually an inverse of surface temperature to wavelength. What that means is the hotter the surface temperature of an object, the shorter the wavelength. The opposite is true as well. As we get a higher micron level, the surface temperature drops and the wavelength becomes longer.
As you see on the infrared chart above, near infrared is represented in the infrared spectrum from .7 microns to 2.0 microns. Using Wein’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 infrared heater must 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. It simply doesn’t penetrate deep enough into your body; it is also much, much too hot for an infrared sauna (2150 °F – 7000 °F). To find out more about near infrared in the infrared sauna environment, click here.
Mid infrared is represented from 2.0 to 4.0 microns and is still far too hot for an infrared sauna (2150 °F – 1100 °F).
Far infrared is where we start to find our sweet spot. To find out how far infrared works in the sauna environment, click the button below.
Difference between infrared and traditional sauna
Most likely you’ve seen traditional hot rock saunas in popular culture or at the gym. They’re simple enough–just wooden rooms with a heater where people sit in towels and sweat. These traditional style saunas have been around for ages, going back to when mankind used to relax in small rooms with fireplaces where stones were heated and then doused with water to generate steam or just left dry. Originally, this was a way for people to take a shower and rinse off before hot running water.
Within the last 30 years, a new variation on the sauna tradition has appeared: infrared saunas. Infrared saunas share the same basic idea and philosophy of their traditional steam sauna counterparts—they raise your body temperature in a controlled situation—but the way infrared saunas accomplish this is quite different.
How Infrared Saunas Work
Infrared saunas work by harnessing the natural energy of the sun–infrared light. Infrared is generated any time an object holds heat and releases that heat into its surrounding environment. When an object is heated its internal molecules charge which then increases that object’s temperature. The object then releases some of this energy in the form of heat, which is actually invisible, infrared light. We can’t see this light but we can feel it as heat! In an infrared sauna, this light is created by passing an electrical current through an infrared-producing conductive material like ceramic clay or carbon fiber panels.
The electric current energizes the conductive material it passes through, and infrared energy is released as hot, invisible light that is able to penetrate a user’s skin without heating much of the surrounding air. We say about 80 percent of the energy released gets absorbed by your body and 20 percent goes into the air.
Infrared Saunas get up above 110 degrees (the operating temperature is 110–140 F) but do not need to get above 180+ degrees in order to elicit the desired healthful response in the human body. They are much more comfortable as a result.
How Traditional Saunas Work
- Traditional saunas generate heat by heating hot rocks which then heat the air. By pouring water onto the rocks it creates steam to increase the air temperature and warms the skin of the sauna user.
- The humid steam and heat created by the boiling water or the water poured on rocks is confined to a small area where a person sits for an extended time in order to reap the associated health benefits.
- Traditional rock saunas generally reach somewhere between 185 and 190 degrees before eliciting the desired healthful sauna response from the human body.
Read more about traditional vs. infrared saunas. [link]
Download "The Infographic Guide to Infrared Saunas"
Near vs. Far Infrared
In order to get the near infrared band of light, you must heat an object to 2,750 °F, which is highly uncomfortable for most people to sit next to. Uncomfortable enough that it would be physically impossible to surround yourself with near infrared heaters 360 degrees around you. This is why only one wall of the near infrared sauna can have the heater panel. Shall I repeat that temperature again? Because near infrared heaters are so hot, in a near infrared sauna there is only one side of the body being heated at a time.
Near infrared sauna enthusiasts claim that near infrared is much better for the skin. However, there is only one direction the near infrared light is coming from in a near infrared sauna; therefore, you have to continuously turn your body like a rotisserie to produce a full body sweat. Moreover, only a fraction of your skin is getting the infrared light waves. This is far from the even, enveloping, 360 degree heat of a far infrared sauna. Yes, you are essentially rotissering yourself.
Far infrared saunas actually came into existence 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. (Why do you think people sit next to fires when it’s cold? Far infrared heat.)
The objective of an infrared sauna is to produce a deep and sustained sweat by raising your core body temperature. In order to raise your body’s temperature, you must heat the body by using the optimal wavelength of light that results from the thermal radiation of an object. This optimal wavelength is the far infrared band of light that is evenly distributed in an infrared sauna. Instead of your body seeing the light photons in the visible spectrum of light, your body feels these light photons as heat!
Far infrared is fantastic for many of the same things that near infrared is great for—a boost in metabolic rate, the burning fat cells, improved circulation, increasing cellular energy, faster skin rejuvenation, and faster cellular perfusion.
However, it is the far infrared wavelength that is much better the infrared sauna environment.
Infrared energy is invisible light that your body can’t see; rather, it feels it as heat. Your body literally absorbs infrared energy (the same energy which comes from the sun) and as a result, charges your body’s electrons and creates thermal heat–thus raising your core temperature.
However, in the infrared sauna environment, your body must be hit on all sides (and from a comfortable enough temperature range) to produce a sweat and stay in the sauna for an extended period of time to sustain that sweat.
For this reason, infrared saunas are the most popular type of sauna in the home. They aren’t overwhelmingly hot like a traditional sauna, nor do they make you spin yourself around next to a heater that’s 2,750 °F like in a near infrared sauna. Far infrared saunas allow for you to get the deepest possible sweat, and sustain that sweat, for 30 minutes. The longer you sweat, the more health benefits you will receive and the more relaxed you’ll be.
I am in no way saying that near infrared doesn’t have therapeutic value; however, in the infrared sauna environment, it is less than ideal as it’s extremely inefficient in using infrared light waves, too hot and too uncomfortable (you have to sit on a stool that you can rotate–not a fixed ergonomic bench and backrest that you can sink into). 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 which will do the same thing a near infrared sauna does–bring blood to the surface of your skin to promote faster healing and pain relief.
Carbon vs. Ceramic Heaters
Ceramic compounds are quite pliable, which means they can be molded into many different states and shapes, including pottery or bricks for buildings. When ceramic compounds are heated, their electrons start to move quickly, generating intense heat. Ceramic material is a powerful conductor of energy with an emissivity rating that is nearly a full 1.0, higher than any other material. This high rating allows ceramic materials to absorb and radiate infrared better than any other material.
The main problem with a ceramic heater, however, is that it actually gets too hot. Ceramic heaters have surface temperatures between 350 and 400 °F. This is not ideal, because it leads to the air inside the sauna becoming so hot that most folks find it uncomfortable. And, as you’ll remember from our discussion of Wien’s Law, that surface temperature isn’t quite at the optimum level–200 °F–needed to create infrared waves of the perfect length for the body.
Carbon materials were a big development in infrared saunas, because as pliable as ceramics are, carbon is even more malleable, which meant that its surface area could be spread out and expanded. This expanded surface area is effective at lowering the surface temperature from ceramic’s roughly 350 °F to about 140 or 150 °F, which is actually a bit too cool when plugged into Wien’s formula above–it doesn’t create infrared waves that are in that perfect sweet spot of length–the kind that will give you the best health benefits.
The emissivity rating for carbon is also lower than ceramic, coming in at an average of .94 or .95. Simply put, carbon does not get hot enough to raise core body temperature on its own because it can’t hold as much infrared energy. Because of this, many sauna companies increase carbon panel surface area to generate more heat, which is effective at raising the air temperature in the sauna, but not as effective at emitting enough energy to really raise the core body temperature.
Carbon/ceramic combo heaters are what I generally recommend. I lead into it after I’ve explained the benefits and drawbacks of the other two options by asking this question: what do you think would happen if you combined carbon and ceramic heaters? As you might guess (since one gets too hot at the surface and the other is too cool), that particular combo creates the most effective type of heater in the industry.
By mixing carbon and ceramic, you get a more emissive heater that has a surface temperature that won’t make the air in your sauna uncomfortable. You also get a combination effect that creates the perfect wavelength for penetrating deep into tissue and driving up a body’s core temperature, causing you to sweat and giving you amazing health benefits.
The emission rating of this material combination is .97, and the heater’s temperature is 200 °F, which gives us our ideal wavelength when plugged into the Wien’s Law of Displacement formula. Also, sitting near a heater with a surface temperature of 200 °F is a heck of a lot more comfortable than being near one that’s up around 400 °F.