I'd like to visualise/measure the flow of air in sauna to optimise the ventilation.
Is there a way to colour the air (non-toxic!!!) so I may watch the flow? Or is there any other accessible technology applicable in the home conditions?
EDIT: Finally I asked a DJ on a wedding for a small amount of the fog-machine liquid and I poured it directly to the sauna stove. It produced some smoke and then it (or maybe rather the gas produced by the heat) started burning, but not with long flames. Apparently the heat wires in the stove are too hot. The produced smoke visualised the air flow sufficiently. The only problem was that the smoke dissolved in the air so farther from the stove it wasn't so distinctive, but it was good enough. Thanks to @dknguyen for the tip how to do it without a fog machine.