Public baths originated when most people in population centers did not have access to private bathing facilities. Though termed "public", they have often been restricted according to gender, religious affiliation, personal membership, and other criteria.

A sauna is a room or building designed as a place to experience dry or wet heat sessions, or an establishment with one or more of these facilities. The steam and high heat make the bathers perspire. A thermometer in a sauna is typically used to measure temperature; a hygrometer can be used to measure levels of humidity or steam. Infrared therapy is often referred to as a type of sauna, but according to the Finnish sauna organizations, infrared is not a sauna.