A 1 person sauna is the smallest real cabin sold, usually a corner unit around three feet square, and it exists because apartments, spare rooms and tight garages exist. It is a genuine sauna rather than a compromise, but the decision to buy one is almost always a decision about space rather than about people.
What it fits into
The appeal is the footprint. A single seat infrared cabin will go into a closet alcove, a bedroom corner or beside a garage door where nothing larger fits, and most run on an ordinary household circuit. If the room you have is the constraint, this is the size that actually gets installed rather than the one that stays on a wish list.
Running cost and heat-up
Small is cheap to run. There is little air and little timber to bring up to temperature, so heat-up is quick and the energy per session is the lowest of any cabin. For someone using it daily before work that matters more than it sounds, because a cabin that is ready in fifteen minutes gets used and one that takes forty does not.
The case for two
The cost step from one seat to two is usually small relative to the total, and a two person cabin lets you lie down, brings a partner in and resells far more easily. If the space allows it at all, most buyers are better served going up one size. Buy the single seat when the room genuinely will not take more.
Traditional or infrared at this size
Almost every one person cabin on the market is infrared, because a traditional heater and its clearances eat a single seat cabin's floor area. If you want stones and steam, you are effectively looking at two person and up. That is worth knowing before you shortlist on size alone.
Questions people ask about 1 person sauna
Can a 1 person sauna run on a normal outlet?
Most single seat infrared cabins do. Confirm the stated amperage against the circuit you intend to use rather than assuming.
Is there a one person traditional sauna?
Very few. Heater clearances make single seat traditional cabins impractical, so this size is almost entirely infrared.
Should I buy two person instead?
If the space allows it, usually yes. The price step is modest, the comfort is much better and it resells more easily.