Face masks for hi alt trekking?

Hi, there are lots of face masks out there at present. In my hi alt trekking I find a buff or balaclava doesn't sufficiently warm the breath and often the condensation is a bit much. Given the huge numbers of masks around in this Covid time I wondered if anyone has a recommendation for a mask that might work at hi-alt.
I am thinking that a mask with a valve may at least partially overcome this problem. (BTW, I am aware health authorities don't recommend them for Covid - but I am only thinking hi-alt.)
I have seen expensive masks advertised for use by outdoor workers in really cold areas. And some have copper mesh valves - the theory being the out-breath warms the mesh which then warms the in-breath. But apart from the cost there seems to doubt if they really work - and the condensation may still be a problem.
Just seems like a good opportunity to test some cheapish masks while mask wearing (here in Vic) is compulsory.
Thanks. Grahame
I am thinking that a mask with a valve may at least partially overcome this problem. (BTW, I am aware health authorities don't recommend them for Covid - but I am only thinking hi-alt.)
I have seen expensive masks advertised for use by outdoor workers in really cold areas. And some have copper mesh valves - the theory being the out-breath warms the mesh which then warms the in-breath. But apart from the cost there seems to doubt if they really work - and the condensation may still be a problem.
Just seems like a good opportunity to test some cheapish masks while mask wearing (here in Vic) is compulsory.
Thanks. Grahame