The exclusivity and capacity of the Athena thermostove exchanger brilliantly avoids the typical problem of all water boilers that exploit wood biomass: the deposit of combustion residues (eg creosote, pitch and others) on cold surfaces. The exchanger, having the fins welded on the contact surface and therefore fixed and non-removable, makes the structure a dry chamber (patented system) which, when the fumes pass, becomes incandescent, exceeding the lysis temperature of the unburnt smoke particles and of the distillates, burning them further. These burning burn deposits produce additional energy and turn into easily removable ash. Throughout the life of the thermo stove, the performance remains constant, from the first to the last day of use, because in the exchanger there is no accumulation of creosote or deposit of unburnts, with the advantage of being able to burn any type of wood without ever getting clogged.