I'm from Finland so I'm familiar with sauna but I've never built one. Now I'm building a house in Vietnam and I'd like to have a sauna. I'm not sure how familiar local builders are with saunas so I think I need to give them precise instructions.
Sauna would be in a corner of the house. There will be another house right next to our house on bottom side of the image, so I can only make holes on the wall on left. Is this layout okay? A door to the shower room, only top bench is shown. Heater is the green box. Fresh air in from the blue hole, near the bottom of the heater. Air out on red vent under the bench. Alternatively, I could leave a gap at the bottom of the door and have outlet vent on shower room. Any opinion which is better? Passive ventilation would be nice but mechanical is possible also.
WIDTH: I'm 190 cm so I'd like 1950 mm long bench, leave 25 mm gap for both ends, so total 2000 mm. For walls: 10 mm wood panel, 20 mm air gap and 75 mm insulation makes it 105 mm thickness. Total room needed 2210 mm. Should I leave air gap also between the brick wall and insulation?
DEPTH: 600 mm for the top bench, 450 mm for the lower bench, 360 minimum for the heater is together 1410 mm. Maybe 1500 mm inside depth to have some margin for the heater.
HEIGHT: At least Harvia and Narvi have resellers here.
Harvia KIP 8 kW minimum 150 mm from floor + 600 mm height = 750 mm.
Narvi NC Electric 9 kW minimum 120 mm from floor + 520 mm height = 640 mm.
Having room height 2200 mm, top bench at 1100 mm, lower bench 700 mm... that makes it lower than Harvia's top. Would it be better to have 2300 mm room height, 1200 mm top and 800 mm lower bench?
Anything else I should consider? 6 kW and 50 mm insulation could be enough for this sauna, especially that the sauna wall is to south direction and it's usually hot weather outside, wall is warm already.