Over the years I’ve sold thousands of infrared saunas, from my days at Sauna Works to my current position with my own company here at SaunaCloud. In that time, the technology has changed and improved, but the questions that customers ask me have, for the most part, remained the same. Those interested in infrared saunas want to know all there is about the health benefits, the science that makes them possible, and how they can get the best value for their money.
As I answer their questions, I always emphasize that nearly every question about far infrared saunas comes down to one very important component: the infrared sauna’s heater. To really learn about which infrared saunas are best and how they work you have to learn about the different types of heaters these machines use. The way I see it, the heater is kind of like the active ingredient in medicine. It’s the part that’s actually doing the work–the whole reason you’re buying a sauna in the first place.
What Is Infrared Light and How Does It Heat Your Body?
The heaters used in infrared saunas are a bit different than the ones you might use in your house, because they don’t just heat air. They actually create infrared light that penetrates your body and warms it that way. That said, when I explain how far infrared saunas work to potential users, I like to start at the most basic level: what exactly is infrared light?
In my experience, a good number of people are confused by the concept of infrared light. In short, infrared light is light that’s invisible to humans, but like visible light, it is electromagnetic energy and takes the form of waves. Also like visible light, it can be focused or reflected. Infrared light can even be harnessed and pointed at objects, which then absorb it. But don’t be scared off by this absorption idea. All types of light penetrate the objects they come into contact with, not just infrared. The difference is what happens after. With traditional light, we see the absorption and reflection manifested as color. With infrared, we instead feel heat on our skin and throughout our body.
If you’ve ever felt heat with your body, and, of course, we all have, then you’ve felt infrared light. Infrared light radiates from one object and penetrates another, thereby transferring energy to the receiving object. This energy is absorbed at the molecular level, which causes thermal motion to occur among the recipient’s particles and electrons. In the simplest terms, infrared light heats your body up by raising your internal temperature.
Here’s my all-time favorite example, the one I tell pretty much any customer who asks me how our saunas work. Imagine walking outside on a hot summer day. You pass a brick building that’s sitting in direct sunlight. Now, imagine putting your hand just a few inches away from the bricks but not touching them. You’re still feeling heat coming off the brick, right? Well, that’s infrared. The sun’s natural infrared light has heated the bricks. The heat is then released in the form of infrared light, which you experience as heat.
What Wavelength of Infrared Is Best?
Up to this point, I’ve talked about infrared energy as light (a form of energy) that is transferred to the body and creates heat. It’s time now to discuss wavelengths. Light is a form of energy that moves in waves. Waves come in different lengths, with gamma rays on the shortest end of the spectrum and broadcast waves on the far long end. The visible light waves that generate the colors we see are toward the center of the spectrum. One of the qualities that defines infrared light is that it has a wavelength that is slightly longer than the end of the visible light spectrum, just past red.
While infrared light waves are too long to be visible, they are the right wavelength to produce heat by transferring radiant energy to objects, which causes a reaction at the molecular level. Between 50 and 65 percent of the average adult human body is made up of water, and water molecules absorb more far infrared waves–which have a slightly longer wavelength than near or mid infrared waves–than the other types of molecules in our bodies. Water actually absorbs the highest amount of far infrared of any sort of molecule on the planet. It’s important to note here that the more infrared energy the body receives, the more infrared energy our water molecules can then absorb, and the more we absorb, the higher our core temperature soars.
When Is an Infrared Heater Producing the Right Wavelength?
So how do you know if the infrared heater in your sauna is producing infrared energy of the right wavelength to properly heat your body and give you the most health benefits? You can determine the wavelength of infrared being created by a heater if you know the surface temperature of a heater using Wien’s Law of Displacement. Here is the formula:
PEW is the wavelength of infrared light measured in microns, and the best micron wavelength to maximize absorption by the human body–the scientists tell us–is 7.90. With our formula in mind, that means the best surface temperature for your infrared heater, if you want your body to absorb as much infrared energy as possible, is 200 °F.
Another thing that you’ll want to know when you’re looking for the best infrared sauna heater is that there is a scale for all materials, called an emissivity rating, that tells us how effective a material is at emitting and absorbing energy. Materials are rated on this scale from .00 to 1.
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Now let’s look at the most common types of infrared heaters, what materials they use, and what kinds of infrared energy they each produce. The effects of each of these heaters is vastly different, and that’s why it’s so important to pay attention to what kind of heater is used in the sauna you’re thinking about buying.
The Three Types of Infrared Heaters
Infrared heaters consist mainly of a certain material which is activated by an electrical current sent through it. The electricity energizes the material, causing it to radiate energy that takes the form of infrared light, which, you’ll remember from above, is invisible but felt by the body as heat.
So what material do most infrared heaters use to create that infrared radiation? The three main types of infrared heaters are: carbon, ceramic, and carbon/ceramic combos.
- 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.
By this point, my opinion on which heater is best is clear. All things being equal, users can get a better sweat with a ceramic heater than with a carbon one, but the incredibly high temperature is just too unpleasant to be near. Carbon heaters, on the other hand, simply don’t generate a suitably high and concentrated amount of heat, which greatly reduces the potential health benefits. And neither creates the ideal wavelength of infrared.
Combination carbon and ceramic heaters, on the other hand, give off the right kind and the right amount of infrared energy at a more tolerable temperature that allows users to stay in their saunas longer. This is more comfortable, and, of course, allows for more useage, which is crucial when it comes to getting health benefits like detoxification. So, yes, most every question-and-answer session I’ve done about infrared saunas over the years starts with the same questions. If I’ve done my job right, it also ends with the same result: a consumer who now completely understands that ceramic/carbon infrared heaters are the best choice for his or her body.