dubba
Gold Member
What makes you say outdoor wood boilers are extremely inefficient?
While I'm not going to argue the "extremely" adjective, there is an inefficiency in changing heat energy. There is are changes that are similar to both appliances but one change stands out.
The outdoor wood boiler must convert the heat to hot water, the hot water must be transmitted to the heated space. As there are no perpetual motion machines in existence, i can suppose a heat loss in this process. Just the fact that there is insulation on the pipes into the house tells me there is heat loss & the manufacturers are trying to mitigate the problem.
Another loss of efficiency for both appliances is sizing them too big. Efficiency ratings are for a steady state full burn condition. As soon as the woodstove or outside boiler is "turned down" efficiency goes through the floor.
The best setup that I have seen is just up the road from me. One man owns 2 houses close together. (~500ft) He put one 130k/btu outdoor wood boiler in between the 2 houses. It has been rocking & rolling for 5 years now. His wood usage? 12-13 cords per year. BOL