Full spectrum vs far infrared
The upgrade roughly doubles your power draw and pushes you to 220 V. Here is what the extra wavelengths actually are, what the research supports, and the cheaper route to the same thing.
The short verdict: far infrared is what a sauna cabin is for, and it is what every cabin produces. Full spectrum adds near and mid wavelengths, roughly doubles the draw, and usually forces a 220 V circuit. If you want near infrared, a standalone red light panel delivers the same wavelengths for less money with far more control over dose. Buy full spectrum when you specifically want it built into the cabin and the wiring is not an obstacle.
What the three bands actually are
| Band | Approximate wavelength | Penetration | Where the research sits |
|---|---|---|---|
| Near infrared (NIR) | ~700–1,400 nm | Deepest of the three | Photobiomodulation — skin and localized tissue |
| Mid infrared (MIR) | ~1,400–3,000 nm | Intermediate | Thinner literature than NIR or FIR |
| Far infrared (FIR) | ~3,000 nm and above | Absorbed at the surface | Whole-body heating; most sauna research |
Band boundaries vary between sources — these are the divisions commonly used in the sauna industry. The key point for a buyer is that far infrared is the heating band and near infrared is the photobiomodulation band; they are doing different jobs.
That last distinction is the one that clarifies the purchase. Far infrared is what makes you hot. Near infrared is what red light panels emit, and the research on it is about cellular and tissue effects rather than about heating. A full-spectrum cabin is, functionally, a far-infrared sauna with red light tubes in it.
What the upgrade costs
- 1Power. A three-person far-infrared cabin draws around 2,100–2,240 W. Its full-spectrum equivalent draws around 3,600 W — roughly a 60% increase.
- 2Voltage. That draw pushes you to 220 V, which means an electrician, likely a permit, and a real install cost that is not part of the cabin's price.
- 3Purchase price. Full-spectrum cabins sit meaningfully above their far-infrared equivalents.
- 4Running cost. Higher, though still modest — 3.6 kW for 45 minutes at $0.17/kWh is roughly $0.46 at the upper bound, against $0.29 for the far-infrared cabin.
What the evidence supports
Near-infrared photobiomodulation has a genuine research literature — Hamblin's open-access review of the mechanisms is a reasonable starting point and is linked below. Much of that work concerns skin, wound healing and localized musculoskeletal effects, at specific wavelengths and specific doses delivered close to the tissue.
That matters for this decision in a way the marketing skips: dose depends on irradiance and distance. Red-light tubes mounted in a cabin wall, several feet from your body, deliver a very different dose from a panel positioned a few inches away. Neither cabins nor panels publish irradiance at a stated distance — see irradiance explained — so nobody can tell you what a given cabin's tubes actually deliver.
The cheaper route
A far-infrared cabin plus a standalone red light panel gets you both bands, usually for less than a full-spectrum cabin, and with two advantages the built-in version cannot match: you can position the panel at whatever distance you want, and you can use it independently of running a sauna session. The red light panel roundup covers the options, and panel vs in-sauna red light makes the comparison directly.
If you already own a far-infrared cabin, adding red light to an existing sauna covers what is genuinely retrofittable and what is not.
When full spectrum is the right buy
- You want it in one box and you value not managing a second device.
- The 220 V circuit already exists or is trivial for you to add, which removes the main cost objection.
- You are buying a cabin anyway and the price gap is small relative to your budget.
- Foot heating and better element placement come with it — several full-spectrum cabins have better internal layouts, and that is a real benefit independent of the spectrum question.
The full-spectrum cabin, and the cheaper alternative
Duthss 3-Person Full-Spectrum Infrared Sauna
Duthss
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Full spectrum at this size means a 220 V circuit, and the listing says so instead of burying it. That single line is worth more than the whole feature list.
| Capacity | 3 person |
|---|---|
| Power draw | 3,600 W |
| Voltage | 220 V |
| Interior | 60" W × 41" D × 75" H |
| Heaters | 4 carbon panels plus 4 red-light tubes |
| Wood | Hemlock |
| Extras | Foot heating, insulated glass |
What works
- Publishes interior dimensions, not just the outside box
- Foot heating addresses the most common complaint about infrared cabins
- The 220 V requirement is stated openly rather than discovered on delivery day
What doesn't
- 220 V means an electrician, a permit in most jurisdictions and a real install cost
- No EMF figure published
- 3,600 W is expensive to run — check the arithmetic before you commit
Skip it ifyou are not prepared to add a 220 V circuit. Budget the electrical work before the cabin, because on this unit the wiring is not optional.
RESTISLAND 3-Person Far Infrared Sauna
RESTISLAND
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It publishes both the wattage and the circuit it needs — the pair of numbers that actually decides whether you can install a sauna where you want it.
| Capacity | 3 person |
|---|---|
| Power draw | 2,240 W |
| Circuit | 20 A |
| Wood | Canadian hemlock |
| Extras | 7-color chromotherapy, Bluetooth speakers |
| EMF, as published | Described as low EMF; no figure given |
| Spectrum | Far infrared |
What works
- States the circuit requirement up front — most listings make you infer it
- 2,240 W is a real number you can run a running-cost calculation against
- Tempered glass door on a sub-premium cabin
What doesn't
- A dedicated 20 A circuit is not optional and most rooms lack a spare one
- 'Low EMF' again carries no figure
- No near infrared
Skip it ifyour only free outlet is on a shared kitchen or bathroom circuit. At 2,240 W this will trip a 15 A breaker, and an extension cord is a fire risk rather than a workaround.
Full-Body Red Light Therapy Panel, 660 nm + 850 nm Dual Chip
Generic Amazon listing
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Dual-chip LEDs put both wavelengths in every diode rather than alternating them across the board, which is what makes coverage even instead of striped.
| Wavelengths | 660 nm red, 850 nm near infrared |
|---|---|
| LED type | Dual chip |
| Coverage | Full-body panel |
| Irradiance | Not published at a stated distance |
| Mounting | Not published |
| Power figure | Quoted as LED rating, not measured wall draw |
What works
- Both of the well-studied wavelengths in every diode
- A full-body board rather than a targeted spot panel
- Wavelengths stated in nanometres, which many listings still avoid
What doesn't
- No irradiance figure at a stated distance — the spec that actually matters
- Advertised wattage is an LED rating, not measured wall draw
- No mounting hardware detail published
Skip it ifyou are trying to choose on irradiance. Nobody in this category publishes it at a stated distance, so you are buying on coverage and wavelength alone.
Questions people actually ask
Is full spectrum infrared better than far infrared?
Does full spectrum need 220 V?
Can I get near infrared without buying a full spectrum sauna?
How much more does full spectrum cost to run?
Sources
Read next
- Irradiance explainedThe spec that determines dose, and why nobody publishes it.Read it
- Panel vs in-sauna red lightBuilt in or standalone, compared directly.Read it
- Best 3-person infrared saunasWhere the full-spectrum options actually appear.Read it
- Red light therapy evidenceWhat the research has and has not shown.Read it
Every pick on this page comes from published specifications, not from hardware we own. Read how we pick — including what spec-led ranking cannot tell you.