Sauna mat is one of the more confusing terms in this category, because it is attached to three products that have almost nothing to do with each other: a duckboard for the cabin floor, a towel-like mat for the bench, and a heated infrared mat you lie on that is not a sauna in any ordinary sense.
The floor mat
A slatted timber duckboard or a perforated rubber mat that lifts your feet off a hot or wet floor, gives water somewhere to go and keeps the floor cleaner. In a cabin with a solid floor it is close to essential, and it is the cheapest of the three by a wide margin. Timber looks right, rubber is easier to lift and hose.
The bench mat
A linen, cotton or felted mat you sit on instead of a towel. It keeps sweat off the timber, which is the main way benches get stained, and it is more comfortable than bare wood at temperature. Two per user is the sensible number so one is always dry, and they wash like any other linen.
The infrared mat
A padded, heated mat you lie on, often with tourmaline or amethyst layers, sold as a portable sauna. It warms your back and it is not a sauna: there is no enclosure, no air temperature and nothing radiating onto your front. Judge it as a heated mat, and treat any health claims attached to the stones with the scepticism they deserve.
Which to buy
If your cabin has a solid floor, a floor mat. If your benches are staining or you find bare timber uncomfortable, bench mats. If you are considering an infrared mat as a cheap way into a sauna, know that it is a different thing: a folding infrared pod costs more and is much closer to what you are imagining.
Questions people ask about sauna mat
Is an infrared mat a sauna?
No. There is no enclosure and no heated air, and it warms only the side of you lying on it. Judge it as a heated mat.
Do I need a floor mat in a sauna?
If the floor is solid, almost certainly. It lifts your feet off hot or wet surfaces and keeps the floor cleaner and drier.
Towel or bench mat?
Either works. A bench mat is more comfortable at temperature and is what most owners settle on once they have tried both.