Finnmark sauna review: the Trinity infrared and traditional combos

In early October Topture showed list prices of $8,999.99 and $9,999.99 crossed out next to these; by Oct 27, 2026 it showed the sale price alone. Another dealer, The Sauna Place, had them at $7,797 and $8,995. Finnmark also makes infrared-only cabins, the FD-1, FD-2 and FD-3, which aren't in our database yet.

In infrared mode, the manual (as quoted by Topture) says the cabin takes 55–60 minutes to reach 170°F. Switch on the rock heater and the brand lists up to 194°F, and you can ladle water on the stones for steam. That second mode is what an infrared-only cabin doesn't give you: the infrared cabins in our database list 140–170°F at most.

The rock heaters are small. The FD-4 uses a Harvia Vega Compact 1.9 kW and the FD-5 a Harvia KIP45B 4.5 kW, where Almost Heaven and Redwood put 6 kW Harvias in their barrels. One discrepancy: Finnmark says the FD-4 has "(3) Spectrum Plus" emitters, Topture says six. Traditional rooms from other brands are on dry saunas.

This is the biggest difference between the two indoor models. The FD-4's infrared side draws 1,750 W and plugs into a 120 V 15 A outlet; its Harvia Vega Compact is also 120 V, at 15.9 A. The FD-5 needs two separate 240 V lines: one with a NEMA 6-15 outlet for the infrared, one hard-wired for the Harvia at 18.8 A.

Finnmark doesn't say whether the FD-4's two 120 V loads can share a circuit. A licensed electrician should decide that, and for the FD-5 you need one anyway.

Every Trinity has an LED panel in the ceiling that Finnmark lists at 650 nm. It doesn't give output or coverage, so there's nothing to compare it with the red light panels we track, and it's not why you'd buy this sauna. I'm not repeating any health claims about it here.

The FD-9 is the outdoor version for two: cedar inside, thermally treated aspen outside, infrared plus a rock heater and the red panel. Finnmark gives it a 20-year warranty on the sauna and unlimited lifetime on the infrared emitters, and mentions a "30-day money-back guarantee." There's no price: Finnmark sends you to a dealer, and Topture doesn't carry it.

The brand's own page can't agree on the heater: a Harvia Vega Pro 1.9 kW in the specs, a "HUUM Steel 6kW Heater" in the description, and a "2-Year HUUM" warranty. That changes the wiring, so get it settled in writing. Other outdoor options are on outdoor saunas.

You pay for having both modes in one room. At two seats indoors, the FD-4 costs $7,795. An infrared-only Health Mate Enrich 2, also full spectrum, is $5,300; a traditional Almost Heaven Madison with a 6 kW Harvia is $5,160. So the Trinity costs $2,495 more than the infrared cabin and $2,635 more than the traditional room, and gives you a smaller rock heater than the Madison's.

It makes sense if you'd really use both: infrared for lower-heat sessions, the rock heater when you want steam and 194°F. If you know you prefer one, buy that one. More on the difference in infrared vs traditional saunas.

The names are close and Google mixes them up, but they're separate companies. Finnmark Designs sells the Trinity combos through dealers like Topture, with prices online. Finnleo, part of Sauna360, sells cabins like the S-820 only through its own dealers and publishes no prices. More in the Finnleo review.

On the FD-4 and FD-5: 10 years on the sauna, lifetime on the Spectrum Plus emitters, 2 years on the Harvia heater. Returns go through the dealer. Topture's policy: ask within 30 days of delivery, the sauna must be new, uninstalled and in its original packaging, with photos, and Topture keeps a payment-processing fee, a restocking fee and freight both ways. Shipping is LTL freight.