Heating with a Wood Furnace
There are both indoor and outdoor wood boilers and furnaces. Outdoor boilers are really big wood stoves with a tank of antifreeze solution or water surrounding them. The burning wood emits heat to the fluid, giving hot water and energy to warm the house. The boiler temperature is regulated by a home control system. Most include an alarm for re-stocking. Furnaces provide warm air; they come as indoor units only.