Most  Saunas are 7' height or lower. Minimum height is generally 75" to 78" depending on heater model.
Our standard kit height is 821/2".
Maximum sauna height should never be higher than 8'.  If you really want higher, we strongly urge being as close to 7' as you are willing to go; i.e. 7'-4" or 7'-6".
To be effective, you must sit where the air is hottest-that is up high.  Comfortable seating height is 18". So standard two tier benches are bottom tier is18" high and top tier is 36" high.
(In larger commercial saunas with 8' height, there may be floor space for three tier benches.)