Indoor saunas are generally more expensive than outdoor saunas, however, since you need the sauna to conform to the space you choose, the sauna has to be vented, and nearby spaces have to be protected from heat and moisture. An average 2-4 person indoor sauna will cost anywhere from $1,500 to $3,000. Labor, along with the electrical work involved for the heater, will usually be around the same price as your sauna cost. A typical 5-7 person sauna will cost $3,000 to $5,000 with labor typically costing $2,000 to $4,000.