The Eco fan will start to rotate once the base of the fan has reached a temperature of 65°C. The optimal running temperature of the Eco fan is the same as the recommended safe operating temperatures of wood stoves, between 205°C - 345°C
It is well worth using a stove top thermometer to ensure good stove safety, but also to build up a more intimate relationship with your stove.
There is a gap between the lower stand of the fan and the upper cooling fins where you find a thermoelectric device; it uses the Seebeck or Peltier effect to convert a temperature difference into an electric potential difference. You can also think of it as converting a flow of heat into a flow of electrons. The screws that hold the halves together are a source of thermal bridging: they move heat from the bottom to the top without it passing through the thermoelectric device. The heat that passes through the screws is thus not converted to electricity, which serves as an inefficiency.
We have a few Eco fans, and highly recommend them. We bought ours in the UK, where you can pick them up for half the price you find them in Sweden. Either way, they make for a very practical and comfortable addition to future- proof wood based heating & cooking. We're into everything performing as many functions as possible, and this is one solid piece of appropriate tech. that makes every piece of wood go as far as possible. Lo