Hi Jacob,
We recently had a kitchen extension making our kitchen into a farmhouse living room approx 9m by 5m. Our 8.5kW woodburner is situated at one end of the room. We bought an Ecofan with our woodburner (the fan looks like the 802 model in your attachment - the one with three blades). We find that the fan gives us two things:-
a) it stirs the air very gently - there is no breeze as such - and that the warmth is circulated around the long room better than if the fan is not used, and
b) the hotter the fire, the faster the fan goes round, so it is a bit like a temperature gauge!! If the fan is going too fast, we shut the fire down, if the fan slows right down we know it is time to refuel the stove and open up the vents (this second benefit is useful if you are, like us, too lazy to keep the glass door clear of soot etc and cannot easily see the fire).
Our Ecofan cost about £110, which was a very small percentage of the overall cost of our extension plus new fitted kitchen, so we did not really notice the cost. Would I buy one retrospectively? Probably not - we do not have one in the other woodburner in the lounge - we just move the one from the kitchen!! (Cheapskates, or what!!).
As they work on the basis of an electro-thermocouple and generate only a very small amount of energy, the fan mounting is very sensitive to being knocked - lots of kids around might not be a good idea either.
Hope this helps,
Mike.