Far infrared vs near infrared: the difference explained
In short
Near infrared and far infrared sound technical, but you mainly notice the difference in how the warmth of a lamp or an infrared blanket feels.
- Near infrared: short wavelength, targeted lamps
- Far infrared: longer wavelength, sauna blankets
- The warmth is mainly linked to the temperature
- Choose between targeted and enveloping, not on technology
Far infrared, near infrared, IR-A, IR-C, FIR, NIR. Product descriptions use these terms interchangeably, sometimes even for the same device. Yet they refer to different parts of the spectrum, and you notice that difference straight away as soon as you lie down under a lamp or get into a sauna blanket.
In this article we list the bands with their wavelengths, explain why one feels warm and the other barely does, how deep they reach, and which type is used in which device. So that you can see what you are looking at in a product description.
The three infrared bands
Infrared starts where visible light ends, just beyond red, and runs all the way to microwaves. That huge range is divided into three bands. The classification below is the standard one, as also used in technical documentation.
| Band | Wavelength | Also known as | Where you come across it |
|---|---|---|---|
| IR-A, near infrared | 780 to 1,400 nanometres | NIR | Red light panels with 850 nm, heat lamps |
| IR-B, mid infrared | 1,400 to 3,000 nanometres | MIR | Part of the light from a glowing heat lamp |
| IR-C, far infrared | 3,000 nanometres to 1 millimetre | FIR | Sauna blankets, infrared cabins with flat emitters |
To line up the units: 3,000 nanometres is 3 micrometres. A sauna blanket works in the range of 3 to 50 micrometres, so firmly in the far infrared band. A red light panel with 850 nm sits right at the start of near infrared. The full classification with all the boundaries is in classification of infrared light: IR-A, IR-B and IR-C explained.
Red light is not infrared
A common mix up: the red light you see in a panel or a lamp is visible light, so it is not infrared. Visible red light lies around 630 to 660 nanometres. Infrared only starts above 780 nanometres and is invisible by definition.
If you do see a red glow from a red light lamp, you are looking at the visible part. You cannot see the infrared part; at most you feel it as warmth. There is more about this in wavelengths of red light and infrared.
What you see is red light. What you feel is infrared. They often come from the same device, but they are two different things.
How deep does it reach?
Penetration depth depends on the wavelength and on how much water the tissue contains. Water absorbs far infrared almost immediately, and your skin consists largely of water. As a result, far infrared stays in the top layer, after which the warmth spreads further through your skin and your circulation.
| Type of radiation | Wavelength | Where it is mostly absorbed | What you notice |
|---|---|---|---|
| Visible red light | 630 to 660 nm | Upper layers of the skin, a few millimetres | You see it, you feel almost nothing |
| Near infrared | Around 850 nm | Deeper than red light, in the order of a centimetre | Invisible, mild warmth |
| Mid infrared | 1,400 to 3,000 nm | Superficial, strongly absorbed by water | Clearly noticeable warmth |
| Far infrared | 3 to 50 micrometres | Top layer of the skin | Gentle, enveloping warmth over a large area |
Watch out for the pitfall in this table: reaching deeper does not automatically mean more warmth. Near infrared reaches further, but actually gives less of a warm feeling than far infrared, which stays just under your skin. That explains why a panel at full power barely feels warm, while a sauna blanket at half that power does.
Why one feels warm and the other does not
A feeling of warmth comes about when radiation is absorbed by your skin and converted into heat there. The stronger the absorption at the surface, the more directly you feel it. Far infrared is almost completely absorbed in the top layer, so you feel it straight away.
On top of that, the power given off varies enormously. A sauna blanket works with hundreds of watts of heating elements over an area of almost one and a half square metres, and you lie inside it, so no heat can escape. A red light panel converts only a small part of the power it draws into light and hangs at a distance.
| Device | Dominant band | Feeling of warmth | Coverage |
|---|---|---|---|
| Sauna blanket | Far infrared | Strong, over your whole body | From your ankles to your shoulders |
| Infrared lamp with filament | Mix of near and mid infrared | Clear, but only where you point it | An area from about the size of a palm to a whole back |
| Red light panel with LEDs | Red light plus near infrared | Barely | The area the panel is aimed at |
What it means for your choice
So the question is not which band is better, but which one suits what you are looking for. Three situations come up most often.
You want warmth over your whole body
Then you end up with far infrared, and in practice with a sauna blanket or a cabin. You lie or sit in the warmth and it takes twenty to forty minutes. The choice between the two is mainly about space and installation, not about the type of radiation.
You want targeted warmth on one spot
Then an infrared lamp makes more sense. The warmth is noticeable straight away and you aim it at the spot you have in mind. Distance and time determine the intensity. That is covered in distance and duration with an infrared lamp.
You want light and no warmth
Then you are looking for a red light panel or an LED mask with red light and near infrared. These devices are deliberately kept cool. If your panel barely feels warm, it is working exactly as intended and nothing is wrong.
If a product description only says far infrared without a wavelength or power rating, that word on its own says nothing about quality. Look at the power drawn, the surface area and the setting range.
- Far infrared across the entire inner surface of 180 by 80 cm
- Adjustable from 30 to 80 °C with a timer up to 60 minutes
- 60 days to change your mind and 2 year warranty
Want to know what has actually been researched for each band and each device? Take a look at what the research says about infrared. It also explains why a result from a cabin does not automatically apply to a blanket.
Common misconceptions
- Deeper is better: penetration depth is a property, not a quality judgement. What you are looking for determines which band suits you.
- Red light and infrared are the same: red light is visible, infrared is not. Many devices give off both.
- More warmth means more radiation: a panel can have a lot of power and still feel cool.
- Far infrared is a quality mark: it is a wavelength range, not a standard and not a certificate.
- Nanometres and micrometres are interchangeable: 850 nm and 8.5 micrometres differ by a factor of ten, and that is the difference between two very different devices.
In closing
Near infrared reaches deeper but you barely feel it, while far infrared stays at the surface and gives exactly the warm feeling you know from a sauna blanket. Once you know which band a device works in, you also know what to expect from it and how much weight to give the marketing copy.
Browse the infrared sauna blankets or the Luxyor red light panels, or read more in the knowledge base on red light therapy.
Frequently asked questions
What's the difference between far infrared and near infrared?
Near infrared, also called IR A, runs from 780 to 1,400 nanometres and goes deeper, but you hardly feel it. Far infrared, IR C, runs from 3 micrometres to 1 millimetre, stays at the surface and gives exactly that warm feeling.
Is red light the same as infrared?
No. Visible red light lies around 630 to 660 nanometres. Infrared starts above 780 nanometres and is invisible. Many devices give off both.
Which type is in a sauna blanket?
Far infrared, in the order of 3 to 50 micrometres, from heating elements across the whole inner surface.
Why does a red light panel hardly feel warm?
A panel mainly works with red light and near infrared. These are converted into heat less at the skin surface, and a panel only converts a small part of its power into light.
Does deeper also mean better?
No. Penetration depth is a property, not a quality judgement. What you're looking for, warmth over your body or light on one area, decides which band fits.
