Far Infrared vs Full Spectrum Sauna: Which Infrared Type Is Right for You?

This article is for general education and isn't medical advice. Check with your doctor before using a sauna if you have a heart condition, high or low blood pressure, are pregnant, or have a medical condition.

If you've decided on an infrared sauna over a traditional model, the next question is which type of infrared. The market splits into two main categories: far infrared (FIR) saunas and full spectrum infrared saunas. The difference comes down to the wavelengths of light each uses — and those wavelengths determine how heat penetrates your body and which benefits you get the most of.

Here's the breakdown so you can match the right sauna to your specific goals.

Understanding the Infrared Spectrum

Infrared light sits just beyond visible red light on the electromagnetic spectrum. It's invisible to the human eye but you feel it as heat. Unlike traditional saunas that heat the air around you, infrared saunas use radiant heat that warms your body directly.

The infrared spectrum divides into three distinct bands, each with different wavelengths and penetration characteristics.

Near Infrared (NIR): 700–1,400nm

Near infrared has the shortest wavelengths in the infrared range — and, counterintuitively, the deepest penetration of the three bands. According to Germany's Federal Office for Radiation Protection, it reaches up to about 5mm into the skin. That's still skin-level, and the skin is where most NIR research focuses.

NIR light is studied in photobiomodulation (light therapy) research — for example, a controlled trial of red and near-infrared light reported improvements in fine lines, skin roughness, and collagen density. Those studies used dedicated light-therapy devices at controlled doses, not sauna heaters, so don't expect the same results from a sauna's NIR emitters. For a deep dive on the research behind photobiomodulation, see our complete Red Light Therapy 101 guide.

If your primary goals are skin health or anti-aging, near infrared is the most relevant wavelength.

Mid Infrared (MIR): 1,400–3,000nm

Mid infrared is absorbed in the outer layer of the skin (the epidermis), according to the same agency. Like the rest of the infrared spectrum, it works by warming you, which increases circulation and can ease muscle tension.

MIR is the least studied of the three bands individually, and there's little research isolating its effects from heat therapy in general.

If you deal with joint pain or stiffness, the general warmth of any infrared sauna is what matters most — mid infrared hasn't been shown to be better for it.

Far Infrared (FIR): 3,000nm–1mm

Far infrared has the longest wavelengths. It's absorbed in the outer layer of the skin, but it's very efficient at warming you — which raises your core temperature and produces a deep sweat.

The majority of infrared sauna research — including small clinical studies such as a pilot study in chronic fatigue syndrome — has been conducted using far infrared saunas specifically. Note that the landmark Finnish cardiovascular studies used traditional Finnish saunas, not infrared, so their results don't automatically apply to any infrared sauna.

FIR saunas are the most common type of infrared sauna on the market, typically the most affordable, and have the deepest body of research supporting their health benefits.

Full Spectrum Infrared: All Three Combined

Full spectrum infrared saunas incorporate emitters that produce near, mid, and far infrared wavelengths simultaneously. The idea is straightforward: instead of choosing one wavelength band, you get all three in a single session.

A full spectrum session delivers all three bands at once — NIR reaching a few millimeters into the skin, with MIR and FIR absorbed at the skin surface and warming you overall. This makes full spectrum the most versatile option, covering the widest range of wavelengths in each session.

The trade-off is that full spectrum saunas are typically priced higher than dedicated FIR models, and some practitioners argue that a dedicated FIR sauna delivers stronger heating because 100% of its output is concentrated on far infrared wavelengths rather than splitting energy across three bands.

Infrared Wavelength Comparison

Which Should You Choose?

Choose a far infrared sauna if: Your primary goals are post-workout recovery, relaxation, or general wellness. FIR has the most research backing among infrared types and is typically the most cost-effective option. If you're buying your first infrared sauna and want the most proven benefits per dollar, far infrared is the move.

Choose a full spectrum sauna if: You want maximum versatility and the widest range of wavelengths in each session. Full spectrum makes sense if skin health is important to you alongside general heat benefits, or if you want every infrared band in one session. The premium price is justified if you'll use and benefit from all three wavelength ranges.

Skip near-infrared-only or mid-infrared-only units. Standalone NIR or MIR saunas are rare in the consumer market, and for good reason — far infrared or full spectrum is the better all-round choice for regular heat sessions. If you specifically want concentrated NIR for skin therapy, a dedicated red light therapy panel is a more targeted (and more affordable) solution than a NIR sauna.

SunRay's indoor infrared saunas are all far infrared with carbon nano heaters and ultra-low EMF — from the SunRay Sedona 1-2 person ($2,798) up to the SunRay Sequoia 4-person ($4,298). Browse them all in our SunRay sauna collection.

What About EMF Levels?

One concern that comes up frequently with infrared saunas is electromagnetic field (EMF) exposure. All electrical devices produce some level of EMF, and since you're sitting inside an infrared sauna for extended periods, it's a fair question.

Quality infrared sauna manufacturers — including Golden Designs, whose models we carry — use low-EMF carbon fiber heating panels that keep exposure well below safety thresholds established by international standards (ICNIRP guidelines). When shopping, look for saunas that publish their EMF readings and test below 3 milligauss (mG) at the seating position.

Both FIR and full spectrum saunas can be low-EMF — this is a manufacturing quality issue, not a wavelength issue.

The Bottom Line

Far infrared saunas are the proven workhorse — most research, best value. Full spectrum saunas add versatility by covering all three infrared bands in one unit, at a higher price point. Both are excellent investments in your health and recovery.

At Peak Flow Fitness, we carry both far infrared and full spectrum models from Golden Designs, one of the most respected names in home infrared saunas. Every model features low-EMF carbon heating panels, Canadian hemlock or red cedar construction, and capacities from 1-person to 6-person units.

Explore our infrared sauna collection and find the right model for your space and recovery goals.

Related reading: Infrared Sauna Benefits · Which Sauna Should I Get? · Traditional vs Infrared Sauna · Red Light Therapy 101