Technology & Science
How Infrared Heating Works
From the electromagnetic spectrum to the skin on your cheek, the physics behind a well-chosen heater
How Infrared Heating Works
Infrared heating works through electromagnetic radiation that travels in straight lines from a heat source and converts to heat only when absorbed by skin, clothing, or other surfaces. It is the same principle that warms you when standing in winter sunlight, and the same principle used in industry to cure paint, shape plastic bottles, and sterilize packaging. What separates a well-engineered outdoor infrared heater from an average one has less to do with wattage and more to do with the wavelength at which radiation is emitted. This page explains in detail why wavelength is the most underrated parameter in radiant heating, and why a heating element with a peak output at 2.2 micrometres delivers significantly better outdoor comfort heating than one that peaks at 1.0 or 1.2 micrometres.
The electromagnetic spectrum
Click a band to read more
Click a band above to read more about what happens there.
Infrared radiation lies between microwaves and visible light, in the low-energy and non-ionising part of the spectrum. It is the same family of radiation as the warmth from the sun and a campfire.
The Spectrum
Where Infrared Radiation Fits in the Electromagnetic Spectrum
The electromagnetic spectrum is a continuous scale of radiation stretching from the longest radio waves spanning several kilometres to the shortest gamma rays smaller than a billionth of a millimetre. All these forms of radiation share the same fundamental nature as electromagnetic waves, but different wavelengths produce entirely different properties. Radio waves pass harmlessly through walls, visible light reflects off coloured surfaces, and highly energetic X-rays penetrate soft tissue. Wavelength determines how radiation interacts with matter and whether it has any biological effect at all.
Infrared radiation sits just beyond visible red light, which is the origin of its name. The prefix infra comes from Latin meaning below, so infrared describes radiation with a wavelength just above that of red light but far below microwaves. Visible light ranges from approximately 0.4 micrometres for violet to 0.7 micrometres for deep red. Where red ends, infrared begins and extends all the way to around 1,000 micrometres. One important clarification: infrared radiation belongs to the low-energy, non-ionising end of the spectrum, the same family as warmth from a campfire or everyday sunlight. It differs fundamentally from high-energy radiation such as ultraviolet, X-rays and gamma rays, which can break chemical bonds in DNA. Infrared photons carry far too little energy per photon to cause that kind of damage. They simply set molecules vibrating, and it is precisely that vibration we experience as heat.
When someone says that a heater emits infrared radiation, very little is conveyed about how it actually behaves. It is a bit like saying a radio station broadcasts on radio frequency without specifying whether it is FM or long wave. The infrared band is so broad that radiation from different parts of it behaves very differently when it interacts with the human body.
Infrared radiation was first discovered by German-born astronomer William Herschel in 1800. Han experimenterade med att bryta upp solljus med ett prisma och mäta temperaturen i de olika färgerna. To his surprise, the thermometer reached its highest reading just beyond visible red light, where no light was visible at all. That was the first evidence that solar radiation extends beyond what the eye can see and that these invisible rays carry heat energy. Over 220 years later, the entire radiant heating industry is built on that discovery.
Every object above absolute zero, which is minus 273.15 degrees Celsius, emits some form of electromagnetic radiation. A freezing object emits only very faint radiation, but it exists nonetheless. A human body at 37 degrees constantly radiates infrared energy into its surroundings, which thermal cameras exploit to detect heat loss in buildings or fever in patients. When you feel warmth from an oven without touching it, you are experiencing infrared radiation. That is the standard mechanism of thermal exchange between physical objects.
Read our introduction to what infrared heating is and the sunshine principle behind the technology.
Wien's displacement law
Temperature determines wavelength — click a peak to compare
The same physical law governs all heat sources. The sun at 5,800 K peaks in visible light, the halogen lamp at 2,500 K peaks in IR-A, and Opranic's IR-B emitter at approximately 1,320 K peaks at 2.2 µm. Wavelength is locked to temperature.
The Physics
Why the Heat Source Temperature Determines the Wavelength It Emits
One of the most misunderstood aspects of radiant physics is this: many people assume you can build a shortwave heater and run it at low power to produce longwave output, or take a longwave source and drive more current through it to increase intensity. Neither works. The wavelength of emitted radiation is physically locked to the temperature of the heat source through a law formulated by German physicist Wilhelm Wien formulerade redan 1893.
Wien’s displacement law states that the wavelength at which a heated object emits maximum radiation is inversely proportional to its absolute temperature. Simply put: the hotter the object, the shorter its dominant wavelength. This is why a heat source glowing red has a longer dominant wavelength than one glowing yellow or white. As a blacksmith heats iron, it progresses from red at around 800 degrees, to orange-red at 1,000 degrees, to yellow at 1,300 degrees, and to white above 1,500 degrees. The same piece of iron, but the spectrum shifts toward shorter wavelengths as temperature rises.
For a radiant heater, this means the design of the heating element, its material, and its operating temperature together lock the manufacturer into a specific spectral profile. A halogen heater with a tungsten filament glowing at approximately 2,200 degrees Celsius will have its peak output around 1.2 to 1.4 micrometres. That cannot be changed. A carbon-based heating element of Opranic’s type operates at a surface temperature of around 950 to 1,050 degrees Celsius at full power, placing its peak output in the optimal range around 2.2 micrometres. The technology and the temperature determine the spectrum together.
Mathematically, Wien’s displacement law states that the peak wavelength in micrometres equals approximately 2,898 divided by the temperature in Kelvin. Some concrete examples: the sun has a surface temperature of roughly 5,800 Kelvin, giving a peak wavelength around 0.5 micrometres, in the yellow-green region of visible light. It is no coincidence that the human eye is most sensitive to green light, as we evolved under the solar spectrum. A halogen filament at 2,500 Kelvin peaks at roughly 1.16 micrometres. A carbon or NiCr-based IR-B heater at approximately 1,320 Kelvin peaks at 2.2 micrometres. A ceramic far-infrared panel at 600 Kelvin peaks at 4.8 micrometres. A wall in a warm room at 300 Kelvin peaks at nearly 10 micrometres.
The same principle explains why an infrared heat source cannot be made more effective simply by increasing its wattage. If you take a longwave source and push more current through it to extract more heat output, its surface temperature rises, shifting the spectrum toward shorter wavelengths. The product changes character. Similarly, if you reduce current to a shortwave heater to lower intensity, the surface temperature drops and the spectrum shifts toward longer wavelengths, but nowhere near enough to produce genuine mid-wave output. Heating elements are engineered around a narrow operating temperature, and departing from it creates compromises in both service life and spectral quality.
For a complete buying guide comparing our models side by side, see outdoor infrared heaters.
IR-X Carbon Black peak output
Wavelength determines whether radiation is absorbed or reflected.
Not wattage.
Three Bands
How Infrared Radiation Penetrates Human Skin
Three bands with distinct characteristics
The infrared region is conventionally divided into three main bands. The classification is based on how radiation behaves when it strikes matter, and human tissue in particular.
Short-wave infrared, IR-A, spans 0.78 to 1.4 micrometres and requires very hot sources with surface temperatures above 1,700 degrees Celsius. The sun is the natural example, while halogen lamps and shortwave heaters are the artificial ones. Mid-wave infrared, IR-B, lies between 1.4 and 3 micrometres and is produced by sources around 600 to 1,700 degrees. Opranic’s IR-X Carbon Black operates here, with a peak output at 2.2 micrometres at full power. Long-wave infrared, IR-C, extends from 3 micrometres up to 1,000 micrometres and comes from cooler sources: ceramic panels, heated surfaces, your own body. The boundaries at 1.4 and 3 micrometres follow the ISO 20473 standard and are conventions rather than sharp physical thresholds, but they capture a genuine difference in behaviour.
Skin acts as an optical filter
When an infrared ray strikes skin, three things happen simultaneously: some is reflected back into the room, some is transmitted deep into tissue, and some is absorbed and becomes heat. The balance between these three outcomes depends entirely on the wavelength of the radiation. This is where the choice of technology has its real practical significance for someone who wants to stay warm on a terrace on a cool autumn evening.
The outermost layer of skin, the stratum corneum, is around 10 to 20 micrometres thick and consists of dead keratin cells and lipids. Beneath it lies the epidermis, approximately 100 micrometres thick, and below that the dermis containing blood vessels, nerve endings, and the heat-sensitive receptors. For radiation to generate a pleasant sensation of warmth, it must be absorbed at the right depth: deep enough to reach the dermis where the receptors are located, but not so deep that it passes straight through without warming anything relevant.
How the three bands behave
Shortwave IR-A between 0.8 and 1.4 micrometres has high transmission through skin. A significant portion of the radiation travels straight through the epidermis and can reach several millimetres into the dermis and subcutaneous tissue. At the same time, skin reflects up to half of shortwave radiation back into the air. The net result is that energy transfer per incident watt is less efficient for comfort heating, even though the radiation physically penetrates the body. It is precisely this deep penetration that can be experienced as a harsh, prickling sensation at high doses from artificial sources at close range. The radiation reaches layers beneath the skin where it generates heat without directly activating the superficial thermal receptors.
Mid-wave IR-B around 2 to 3 micrometres behaves differently. Skin reflection is much lower in this range, and absorption is high in the uppermost skin layers where thermal receptors are most densely concentrated. The radiation does not penetrate deeper than around 1 millimetre into the skin, but that is precisely where it needs to be absorbed to deliver a comfortable warmth without surface burning. Blood circulation then distributes the heat through the body naturally.
Long-wave IR-C above 3 micrometres is absorbed almost entirely in the outermost skin layers, often within less than 0.1 millimetres. This produces a sensation of surface warmth that is very pleasant indoors, but outdoors the intensity from longwave sources is generally too low to deliver any meaningful comfort against wind and cold.
Right depth, right receptors
The absorption profile of mid-wave infrared aligns with skin anatomy in a way that is no coincidence. The thermal receptors in the epidermis and dermis sit at a depth where IR-B radiation is absorbed effectively, while IR-A passes beyond them and IR-C is stopped in the dead surface cells before any signal reaches the nervous system. For a heater designed for outdoor human use, the IR-B band is therefore the functional sweet spot where radiation, skin, and thermal comfort converge.
IR-B is also well established in physiotherapy and is used in medically approved heat sources for newborns in neonatal units. Infrared radiation is not an exotic technology, but a well-characterised heat source with a thoroughly documented safety profile.
Infrared wavelengths and water absorption
Select IR-X power level
Power
100 %
Filament
1050 °C
Wavelengthstopp
2,2 µm
Opranic IR-X uses continuous voltage dimming, which means the filament temperature and radiation wavelength shift depending on the selected power level. Drag the buttons above to see how IR-X slides across the optimal water absorption range, from 2.2 µm at P5 to 2.7 µm at P1. Curves are calculated from Planck's radiation law.
Three technologies compared
The Engineering Rationale Behind 2.2 µm
The Human Body Is Mostly Water
When we talk about how infrared radiation warms a person, what we are really talking about is how it warms water. An adult human body is approximately 60 to 70 percent water. Every skin cell, every blood vessel, every muscle contains water that dominates how the body interacts with electromagnetic radiation in the infrared region.
The water molecule has a well-characterised absorption curve. It is not uniform but has distinct peaks and troughs. Water absorbs poorly at visible light and short-wave IR-A around 1 micrometre, which is why the ocean is transparent to visible light and why shortwave radiation passes easily through skin. At around 1.45 micrometres, absorption begins rising sharply. Between 1.9 and 3.0 micrometres lies an absorption band so strong that a water film just a few tenths of a millimetre thick absorbs almost all incident radiation. The peak absorption value sits around 2.9 to 3.0 micrometres.
Why 2.2 and not 3.0
A subtle but important point: if 3.0 is the absorption peak, why does an optimised heating element emit at 2.2 rather than 3.0? The answer lies in a trade-off between two competing requirements.
On one hand, you want the radiation to be absorbed by water in the skin, which favours a longer wavelength. On the other hand, the heat source must produce sufficient power density to feel genuinely warm in wind and cold, which favours a shorter wavelength where surface temperature is higher according to Wien’s displacement law. At 2.2 micrometres at full power, these requirements meet optimally. Water absorption is still high, while power density is sufficient for commercial outdoor use.
At lower power levels, the peak shifts toward longer wavelengths, moving even closer to water’s absorption maximum, which produces a softer warmth experience. The interactive graph above shows how the wavelength slides between 2.2 and 2.7 micrometres depending on the selected power level. This entire range falls within a window where skin reflection is low, as seen in the previous section. This creates a double optimisation targeting both the surface layers of skin and the water molecules within the tissue.
Why not even longer wavelengths
At wavelengths above 3 micrometres, the surface temperature of the heat source drops low enough that power density falls dramatically. Power density is the amount of watts per square metre of radiating surface, and this follows directly from the Stefan-Boltzmann law: radiated power per unit area scales with temperature to the fourth power. A heater at 400 degrees Celsius radiates less than one sixth of the power per unit area compared to a heater at 900 degrees.
This is why long-wave IR-C works excellently indoors, where moderate power density is sufficient and no wind interferes, but proves inadequate for open terraces where convective heat loss is high.
Shortwave has its place, but with a trade-off
In extremely exposed environments and at very low temperatures, a shortwave heater with high power density can feel noticeably warmer than a mid-wave heater at the same distance. This is not because shortwave is better for the skin, but because its surface temperature is so high that raw watts per square metre dominate over absorption optimisation. The trade-off is poorer skin adaptation, a higher proportion of reflected energy, and radiation that is often experienced as harsh and prickling over time.
For properly designed outdoor terraces with moderate wind protection, a mid-wave IR-B heater peaking around 2.2 micrometres is almost always the more balanced choice, both for comfort and for long-term skin health. Shortwave is a legitimate option in extremely exposed, industrial-style environments with short exposure times, but one should be aware that it represents a compromise in skin comfort in favour of raw power density.
Industrial expertise in mid-wave infrared has existed for decades. Opranic has applied it to outdoor comfort heating.
Molecular Level
How Infrared Heating Works at the Molecular Level: Vibrations Become Heat
A common misconception is that infrared radiation is itself heat travelling through space. The radiation is electromagnetic energy travelling as waves, and heat only arises when that energy is absorbed by matter and converted into molecular motion. This distinction is fundamental to the entire technology of radiant heating and explains why it behaves so differently from convective heating.
All molecules consist of atoms held together by chemical bonds. These bonds can be described as tiny springs, and the atoms vibrate around their equilibrium positions. Each molecule has specific vibrational frequencies that are characteristic of its structure. When an electromagnetic wave with a frequency matching a molecule’s natural vibrational frequency strikes it, energy is transferred resonantly and the molecule begins vibrating more strongly. This process is called vibrational resonance, and it is what converts infrared radiation into heat.
The water molecule, H₂O, has three main vibrational modes: symmetric stretching, asymmetric stretching, and bending of the bond angle between hydrogen and oxygen. These modes have resonant frequencies corresponding to wavelengths around 2.7, 2.9 and 6.3 micrometres. This is why water absorbs so strongly in the 2 to 3 micrometre band. The infrared waves match the natural vibrations of the molecules and energy is transferred efficiently. When a water molecule vibrates more strongly, that is precisely what defines a higher temperature. The energy has transitioned from an electromagnetic state to thermal energy in the tissue.
This also explains why infrared radiation can warm a surface without warming the air in between. The main components of air, nitrogen and oxygen, are so-called homonuclear molecules with very few vibrational modes that match the infrared spectrum. Nitrogen absorbs almost nothing in the band where comfort heaters operate. The radiation therefore passes through air with negligible loss until it strikes a water-containing surface, a person, a plant, or a wooden floor, where it is absorbed and becomes heat.
An elegant consequence is that the air between the heater and you remains relatively cool even when the warmth in the radiant field is comfortable. One important practical nuance must be noted here. The infrared radiation itself is not blown away by wind, as it travels in straight lines regardless of air movement. However, the skin simultaneously loses heat to the surroundings through convection, and that convective loss increases sharply with wind speed, the same principle that makes a windy day feel much colder than a calm day at the same air temperature. On a windy day, you therefore need to compensate with higher radiant intensity or shorter distance, not because the radiation itself is diminished, but because the body is losing more heat to the moving air. This is a significant difference compared to convective heaters, which become essentially useless in wind. A well-placed IR-B heater delivers warmth even in windy conditions, it simply needs to supply slightly more energy to offset the increased convective cooling of the skin.
Carbon dioxide and water vapour in the air do make a small difference. These molecules have vibrational modes in the infrared region and absorb certain parts of the spectrum. That is why the atmosphere produces a greenhouse effect at all. But over the distances involved on a terrace, a few metres, this absorption is entirely negligible. The radiation reaches you in practice unchanged.
The same physical principle governs the choice of IR band in industry and on the terrace. IR-B at ~2.2 µm matches the resonant frequency of OH bonds in organic materials — water, plastic, paper and human skin respond identically.
Industrial Engineering
The Same Physics Used When Industry Heats Plastics and Dries Paper
It is tempting to assume that the discussion of wavelength and absorption is academic. It is not. The same wavelength selection that makes 2.2 micrometres optimal for human comfort heating also makes other wavelengths optimal for completely different industrial applications. Infrared technology is used on a large scale to cure paint, form plastic bottles, sterilise packaging, harden adhesives, and much more. In every case, wavelength is chosen to match the specific material being heated.
Plastics, for example, absorb infrared radiation primarily in the range above 2 micrometres. Thin plastic film used in food packaging absorbs shortwave radiation from halogen lamps very poorly, but absorbs mid-wave radiation efficiently. This is why modern PET bottle-forming machines use mid-wave infrared to heat preforms before blowing. Textiles, paper, and wood, all organic materials containing water or OH bonds, absorb best in the same band as human skin. The reason is that they contain molecular structures similar to water or other vibration-sensitive bonds.
Shortwave radiation is used in industry primarily when heating thick, pigmented materials that absorb across many wavelengths, such as sheet metal, dark rubber, or automotive body parts. There, shortwave delivers high intensity and deep penetration. For a terrace where people sit and socialise, the requirement is the opposite: you want the energy to remain in the surface of the skin, not penetrate deeply. Using a shortwave heater for comfort heating is, from an engineering perspective, like choosing an industrial curing lamp when you simply want to read a book.
Heraeus, one of the world’s leading manufacturers of industrial infrared systems, publishes technical data showing exactly the same physics that Opranic applies on the consumer side. When a Swedish restaurant owner buys an Opranic heater for their outdoor terrace, it is the same optical principles that heat PET bottles in a German factory or dry printing ink on a Belgian press, simply applied to an outdoor terrace and a human body.
Safety
Infrared Radiation at Comfort Levels Is Safety-Assessed by International Experts
The International Commission on Non-Ionizing Radiation Protection, ICNIRP, is the global reference body for safety guidelines on electromagnetic radiation below ionising levels. It publishes exposure limits that national authorities worldwide use as reference, and its guidelines for infrared exposure are well established.
Infrared radiation belongs to the non-ionising part of the spectrum, meaning photons lack sufficient energy to break chemical bonds in DNA. This is a fundamental difference from ultraviolet radiation, which is ionising and can cause skin cancer at high exposures. IR radiation at comfort levels has no such mechanism to be concerned about. The only safety parameters ICNIRP focuses on are thermal effects: ensuring that skin or eyes are not exposed to radiant intensity high enough to cause tissue overheating.
For a typical terrace installation, the radiant intensity from a correctly mounted infrared heater, such as a PRO V70 at 2.5 metres height, falls well below the limits ICNIRP sets for several hours of daily exposure. The product design, mounting distance, and power distribution ensure this. Eye safety is also well assessed. While direct eye contact with a very hot halogen or shortwave heater can cause discomfort, the diffuse radiation from a correctly installed mid-wave heater at comfort levels is assessed as safe for normal use.
A subtle advantage of mid-wave heaters at 2.2 micrometres is that absorption of radiation in the front of the eye, the cornea and aqueous humour, is very high at these wavelengths. This means the radiation does not penetrate as deeply into the eye as shortwave can. Short-wave IR-A between 0.8 and 1.4 micrometres passes through the cornea and can reach the retina at considerably higher intensity, which is one of the reasons ICNIRP sets stricter exposure limits for shortwave exposure. In practice, all these levels are far from the everyday exposure from a well-designed comfort heater, but as an engineering principle it is wise to choose a technology that naturally sits on the safer side.
Regarding skin health, a scientific discussion has emerged in recent years about whether intense IR-A can contribute to oxidative stress and collagen degradation. The research is mixed. Dermatological experts generally do not consider natural solar IR-A harmful at normal doses, and infrared radiation has been used medically for wound healing and skin therapy for decades. However, some studies indicate that artificial shortwave sources at close range can generate free radicals in the deeper layers of skin. This is a further reason to prefer mid-wave at 2.2 micrometres for comfort heating. The radiation is absorbed in the outer millimetre of skin and does not reach the fibroblasts in the dermis in the same way.
Infrared radiation for de-icing of wind turbine blades under Arctic conditions
Longer wavelengths are more effective at keeping energy in the surface, because absorption is higher in that part of the spectrum. A combination of infrared heaters with different wavelengths provides a broader spectrum and thus more effective results.
— Conclusion, Journal of Wind Engineering and Industrial Aerodynamics, 2019
Independent Evidence
Luleå University of Technology Validated Wavelength Performance Under Arctic Conditions
In April 2019, an independent experimental study was conducted at Luleå University of Technology in collaboration with Vattenfall’s research and development division. The purpose was to investigate whether infrared radiation can be used to de-ice wind turbine blades under Arctic conditions, a problem that costs the Scandinavian wind power industry significant production losses every winter. Opranic supplied the radiation sources for the study: two specific types, IR-X heaters with a peak output at 2.4 micrometres and halogen heaters with a peak output at 1.4 micrometres.
The study was published in Journal of Wind Engineering and Industrial Aerodynamics and is openly available as peer-reviewed research. Tests were carried out in climate chambers at the Arctic Falls facility in Piteå, where ambient temperature could be controlled between 0 and minus 30 degrees Celsius. The blades were coated with soft rime frost using snow machines and then heated using various combinations of infrared heaters at distances of 1.0 and 1.5 metres.
The results are technically significant and confirm several principles on which Opranic has built its products for over 20 years. First, the study showed that the combination of IR-X and halogen delivered the most effective de-icing result at 1.5 metres distance, with a melting rate of 0.20 kilograms of ice per minute. The combination using only IR-X at the same distance melted 0.13 kilograms per minute. Second, the study showed that the IR-X heater delivers a broader heat distribution while halogen delivers more concentrated heat, exactly as Wien’s law and radiation physics predict. Third, and this is critical for the comfort heating side, the researchers concluded that longer wavelengths are more effective at keeping energy in the surface, because absorption is higher in that part of the spectrum.
An additional observation: when the distance was too short, at 1.0 metre, the surface temperature of the blade became high enough to risk overheating. At 1.5 metres, uniform heat distribution was achieved without overheating. This is an instructive lesson for consumers too: the distance from an infrared heater to the people beneath it matters, and a well-positioned unit at the correct height delivers even comfort without hot spots.
The study also noted an interesting difference between the two wavelengths against different ice types. The IR-X heater at 2.4 micrometres was more effective against light snow and rime frost, as these porous ice crystals contain a lot of air and less densely packed water. The halogen heater at 1.4 micrometres was slightly better against clear glaze ice, which has a different optical structure. Kombinationen av båda gav den bästa totala prestandan, eftersom the two wavelengths covered different ice crystal types. It is an elegantly engineered solution built on an understanding of the role of wavelength.
The researchers’ closing statement in the publication is worth highlighting: a combination of two types of infrared heaters with different wavelengths provides a broader spectrum and thus more effective de-icing, outperforming a combination of only the same type. For an outdoor comfort heater, the conclusion is that a well-engineered mid-wave heater delivering a moderately broad spectrum around 2.4 micrometres becomes a technically well-balanced choice, not so narrow that it misses surrounding wavelengths, not so broad that energy is wasted on wavelengths where skin and water do not absorb efficiently.
Practical Guide
How Infrared Heating Works in Practice: Reading a Product Specification
When buying an outdoor infrared heater, wavelength is rarely the first thing marketed, but it is the most important thing to look for. Here is a framework based on the physics covered on this page.
First, look for information about the spectral peak or dominant wavelength. A manufacturer that understands its technology and is transparent about it will specify that the heater has a peak output in IR-B, ideally with an exact figure in micrometres. If the specification only mentions wattage, or uses vague terms such as “warm heat” or “deep-heating”, the product is difficult to evaluate technically. It need not be a red flag, but it provides no data on which to base an informed decision.
Second, examine the heat source. Halogen and shortwave quartz elements operate in the IR-A band with a peak around 1.0 to 1.4 micrometres. They are used where rapid heating of dense materials is required, or in extremely exposed environments where raw power density matters more than absorption quality. Carbon and NiCr-based heating elements operate in the mid-wave range around 2.0 to 2.5 micrometres and are engineered for comfort, with a focus on skin absorption and long-term pleasantness. Ceramic and FIR panels operate in the longwave above 3 micrometres and are suited for indoors where wind and large volume losses are not a factor.
Third, consider the system surrounding the heating element. The geometry, material, and surface finish of the reflector determine how much of the energy is directed toward you and how much is lost sideways and upward. A perfect IR-B element with a poor reflector delivers less comfort than a well-engineered system using the same element. Opranic has for more than 20 years developed this as a complete system: heating element, reflector, housing, and electronics together.
Also consider the installation environment. For relatively sheltered terraces, restaurants, and residential gardens, a mid-wave IR-B heater is almost always the best choice, both for comfort and for long-term skin health. For extremely exposed, industrial-style environments with short exposure times, such as harbours or open railway platforms, shortwave technology can sometimes be a legitimate choice thanks to its raw power density, but one should be aware that the radiation is more demanding on skin and that prolonged direct exposure should be avoided.
Finally, do not let a low price be the deciding factor alone. A heater that physically operates in the wrong wavelength band will never deliver the same comfort regardless of how cheap it is, just as an FM radio will never receive longwave transmissions regardless of how high you turn up the volume. Physics sets the limits, and the physics of infrared radiation has been well understood for over a hundred years. It pays to choose a product designed with that knowledge at its core.
To understand how wavelength affects real-world performance, read more about Opranic-teknikens grundprinciper, see our köpguide för infravärmare utomhus, or how IR-X Carbon Black is integrated in PRO V70.