What Is a Far Infrared Sauna? The Plain-English Guide

Updated July 2026. The plain-English explainer: what far infrared actually is, how a FIR sauna heats you, how it differs from every other sauna type, and what owning one involves in a UK home.

The Short Version

A far infrared (FIR) sauna uses carbon or ceramic panels that emit long-wavelength infrared light. Instead of heating the air like a traditional sauna, the infrared penetrates and warms your body directly — so the cabin sits at a gentle 45–65°C while you still sweat as deeply as you would at 85°C in a Finnish sauna.

What "Far" Infrared Means

Infrared light spans three bands. Near infrared penetrates shallowest and is studied for skin renewal. Mid infrared reaches soft tissue and is associated with muscle recovery. Far infrared is the longest wavelength, penetrates deepest, and is the band most studied for circulation, relaxation and heat-exposure benefits — which is why most infrared saunas use it exclusively. Cabins combining all three are sold as full spectrum, typically £1,000–£2,000 more.

How a Session Feels

Different from a traditional sauna, and worth knowing before you buy. The air is warm rather than fierce — you can read, listen to music, or talk comfortably. The sweat builds gradually over 15–20 minutes and gets genuinely heavy by the end of a 30–45 minute session. No steam, no löyly, no gasping heat — if you specifically want that intensity, read our infrared vs traditional comparison first.

The Practicalities

Power: most 1–2 person FIR cabins plug into a standard UK 13-amp socket; larger cabins need a 20-amp circuit (electrics guide). Heat-up: 10–20 minutes from cold. Running cost: £0.35–£0.75 per session (running costs guide). Installation: flat-pack panels, 1–2 hours with two people, no plumbing or flue — placement options in our where to put a home sauna guide. Maintenance: a timber wipe-down; there's no water or chemicals involved.

What to Look For When Buying

Low-EMF certification — the main quality divider between cheap and premium panels. Timber — Canadian hemlock or spruce interiors are low-resin, smooth and durable. Heater coverage — panels surrounding you (including calf-level) beat a couple of rear panels. UK warranty and support — the thing sub-£1,500 imports usually lack. Full pick-by-pick recommendations in our Best Infrared Saunas UK guide.

Prices

Quality FIR cabins run £2,095–£6,495 in the UK depending on size — full breakdown in the price guide, or browse the far infrared collection directly. Questions? 0330 133 6617.

FAQs

What is a far infrared sauna?

A sauna that uses carbon or ceramic panels emitting long-wavelength infrared light to heat your body directly, producing a deep sweat at a gentle 45–65°C rather than heating the air to 80–95°C like a traditional sauna.

Is far infrared the same as full spectrum?

No — far infrared is one band. Full spectrum cabins add near and mid infrared for skin and muscle recovery benefits, typically at a £1,000–£2,000 premium.

Does a far infrared sauna get hot?

The cabin air reaches 45–65°C — warm rather than fierce — but because the infrared heats your body directly, the sweat response matches a much hotter traditional sauna.

Is far infrared safe?

Far infrared is simply radiant heat — the same wavelength the sun and any warm object emits — and is widely considered safe for healthy adults. Choose low-EMF certified panels, and check with your GP if you have a health condition.