Dry sauna vs wet sauna sounds like two products, and in a showroom it often is, but in a traditional cabin it is mostly one product run two ways. Pour water on the rocks and a dry sauna becomes a wet one for a few minutes. What separates them as a purchase is the heater, the rock mass and how the cabin handles moisture.
The same cabin at two humidities
A traditional sauna sits dry until you ladle water over hot stones, which flashes to steam and lifts the humidity sharply for a short burst. Finns call that loyly and build for it. Run the same cabin without water and you have what American showrooms sell as a dry sauna. The cabin barely changes; the experience does.
Where the heater decides it
A heater with a generous rock load can absorb water and give you steam without collapsing in temperature, so it runs wet happily. A small heater with a thin tray of stones cools the moment you pour and takes minutes to recover, so it is a dry heater whatever the listing says. Rock capacity is the specification to read.
Infrared is neither
An infrared cabin is sometimes called a dry sauna because it is dry, but it is a different machine: panels warm your body rather than heating the air and its rocks do not exist. You cannot pour water in one. If a listing offers you a dry sauna and shows panels rather than a stove, know that you are buying infrared.
What to build for if you will run it wet
Running wet asks more of the cabin. You want a wood that handles moisture and stays cool to the touch, a floor that can take splashes and drain or dry, a vent path that clears humid air after the session, and benches you can lift to dry underneath. None of it is expensive at build time and all of it is awkward to retrofit.
Questions people ask about dry sauna vs wet sauna
Is an infrared sauna a dry sauna?
It is dry, but it is not the same thing. Infrared heats your body with panels and has no stones, so you can never run it wet.
Does running it wet damage the cabin?
Not if it was built for it. A cabin with good ventilation and a floor that tolerates water dries between sessions. Problems come from sealed, unvented rooms.
Which is better for you?
Neither is established as better. The evidence on heat exposure does not separate them, so choose on comfort and on which one you will actually use.