According to Lesley :

I have a Jotul Allagash natural gas-burning stove and I was thinking
about getting this type of fan for it. I know the Jotul has it's own
electrically-powered fan, but I thought if this one that doesn't need
electricity actually worked, it would be great to use that instead. We
recently had a 4-day power outage. . .although I had some heat because
of the gas stove, it would have been nice if I could have moved the air
around a bit. An added bonus is that it costs more than $100 less than
the Jotul blower unit, PLUS I don't have to pay anyone to install this!

As others have said, the heat-powered one isn't going to be terribly
useful, especially when you really need it to push hard (during a power
outage).

Our wood stove has a built in electric fan, of the 1/12 HP variety.
Given the layout of the house, it can heat the whole place _if_
the fan is operational.

When the power dies, we run the fan off a 400W inverter and a battery
from a recently deceased vehicle. That size inverter is available for
under $50 these days.

The combo is capable of running the fan full blast for several days,
and can be used to provide power for other things. Like a CF
lightbulb and the radio. TV and dish receiver too if we're
feeling really bored ;-)
--
Chris Lewis,

Age and Treachery will Triumph over Youth and Skill
It's not just anyone who gets a Starship Cruiser class named after them.