posted 5 years ago
Hello, I'm currently in the process of designing a sauna stove based on a rockety-type design. Your space is about typical "apartment building sauna" size, so you will need about 5kW of power for a good stove, and about 60-70lbs of stones. The "mass" part of the design will not help you that much, because the aim is to heat the stones and the air, not the bench. In a good sauna, the air will be around 80*C or 175*F when properly heated (although I have personally pushed max temps in a wood fired sauna to 130*C or 266*F - but do not recommed this, as it causes the resins to drip from the wood paneling). You will need a relatively large burner, but could use the flue from the stove to heat water. Equally important is to properly insulate AND ventilate the room. No gaps in the top or sides of the doorframe, bottom can be open a few inches, cold air inflow midwall, directly above the stove (so it gets heated instantly when coming in), adjustable air vent (made of something other than metal - gets hot!) in the opposite top corner from the stove. If you're willing to wait about 9-12 months, I may have a ready product and the designs available.