Three bands of infrared, roughly
Infrared is light just past red, too long for the eye to see. The International Commission on Illumination splits it into three bands: IR-A from about 700 to 1,400 nanometers, IR-B from 1,400 to 3,000, and IR-C from 3,000 nanometers up to a millimeter. Sauna makers call these near, mid and far infrared, though the exact boundaries they quote vary from brand to brand.
What matters in a sauna is the heater's surface temperature, because that sets which band it mostly gives off. Physics (Wien's law) puts the peak of a heater panel running around 150 degrees F at roughly 8 to 9 microns, which is far infrared. To give off much near infrared, an emitter has to be far hotter: well over 2,000 degrees F, which is why near infrared in saunas usually comes from halogen or quartz-tube elements rather than flat carbon panels.
What "full spectrum" means in practice
- Far infrared saunas use carbon, ceramic or carbon-ceramic panels spread around the cabin. They warm the air to roughly 115 to 130 degrees F (Clearlight's stated range for its cabins) and warm you directly.
- Full spectrum saunas keep the far infrared panels and add one or more hotter elements for near and mid infrared. Clearlight's Sanctuary line describes its heaters as near, mid and far, with full spectrum heaters on the front wall. Its product page does not say how each band is produced, so ask if it matters to you.
- Price: full spectrum usually costs more. One maker lists its far infrared and full spectrum cabins roughly $1,100 apart. Treat that as one example, not a market rate.
What the research covers
Heat has the strongest evidence of anything we cover, but most of it is traditional Finnish sauna, not infrared. A 20-year study of 2,315 Finnish men found that more frequent sessions were associated with lower risk of fatal heart disease. That is an association, and it is a hot-air sauna.
Infrared research is smaller, and it is nearly all far infrared. The best known trial used 60 degrees C (140 degrees F) far infrared sauna in 149 people with heart failure. It missed its main goal but improved walking distance and heart size. A review of 40 studies across both sauna types found mostly positive effects, with few randomized trials, most of them small.
Near infrared has its own research under the name photobiomodulation, but those studies mostly used LED panels a few inches from the skin at set wavelengths, not sauna heaters across a cabin. We found no trial that compared full spectrum and far infrared saunas head to head. So the honest summary: full spectrum is plausible, and unproven as a step up.
How to choose
- Pick far infrared if price matters most, or if you want the type the infrared studies actually used.
- Pick full spectrum if you like the feel of the hotter near infrared element and the price gap is small for the build you want.
- Either way, the cabin decides more than the label: wood, heater coverage, warranty and whether it fits your power and space. See infrared vs traditional sauna and home sauna: 120V or 240V?.
The saunas we rate
-
Clearlight Sanctuary 1 (full spectrum) Editor's Pick
One person, standard 120V outlet. We earn nothing on it; the brand excludes it from commission. Our rating. -
Clearlight Sanctuary 2 (full spectrum) Meets the Standard
Two people, on a dedicated 20A, 120V circuit. Our rating. -
Sun Home Luminar 2-Person Outdoor (full spectrum) Meets the Standard
Needs a dedicated 240V circuit. Our rating. -
HigherDOSE Infrared Sauna Blanket (far infrared) Meets the Standard
No cabin, no install. Our rating.
Every rating uses the same five scores: the TMR Standard.
Questions people ask
Is full spectrum better than far infrared?
Not on current evidence. Most infrared sauna studies used far infrared, and we found no trial comparing the two.
Does near infrared in a sauna do the same thing as a red light panel?
Not necessarily. Red light studies mostly used LEDs at set wavelengths, close to the skin. A heater across a cabin delivers a different dose. See how to choose red light therapy.
Does full spectrum get hotter?
The near infrared element itself is hot and can feel intense up close. Cabin air temperature depends on the whole heater setup, not the label.
Is full spectrum the same as a hybrid sauna?
No. A hybrid usually means infrared panels plus a traditional rock heater. Full spectrum means more than one infrared band.
Brand pages read October 19, 2026 unless marked otherwise.
- CIE infrared bands (IR-A, IR-B, IR-C), as tabulated in the photobiologyWavebands reference. docs.r4photobiology.info
- Clearlight, sauna overview (full spectrum description, 115 to 130 degrees F operating range). infraredsauna.com
- Clearlight Sanctuary 1 product page (heater layout, 120V). infraredsauna.com
- Sun Home, "Full-Spectrum vs. Far Infrared Sauna: Is the Upgrade Worth It?" (vendor source; halogen emitters, panel temperatures, the price gap example). sunhomesaunas.com
- Laukkanen T, et al. Association between sauna bathing and fatal cardiovascular and all-cause mortality events. JAMA Intern Med. 2015;175(4):542-548.
- Tei C, et al. Waon therapy for managing chronic heart failure: the WAON-CHF study. Circ J. 2016;80(4):827-834.
- Hussain J, Cohen M. Clinical effects of regular dry sauna bathing: a systematic review. Evid Based Complement Alternat Med. 2018;2018:1857413.
- Wien's displacement law (peak wavelength = 2,898 micron-kelvin divided by temperature in kelvin): standard physics; the 8 to 9 micron figure is our own calculation.