Outdoor furnaces are basically wood fired boilers housed outside of a home. The heat source and the place to be heated can be as much as a hundred yards apart. The furnace can heat either glycol or water where it’s pumped through insulated pipes to your home. The hot liquid can provide heat in many ways such as liquid to liquid heat exchanging, direct heat, and through a hot air radiator. In a liquid-to-liquid heat exchanging system, the heated liquid enters a large storage tank containing coils of copper tubing. Water in the tubing is heated and this flows through the hot water baseboard system in your home and supplies all your hot water needs. Direct heat is when heated liquid enters the home, it goes directly into the home’s hydronic system and indirectly heats the hot water in a separate system. When using a hot air radiator, heated liquid can be pumped through inside the plenum of a forced-air system. Using the ductwork of an existing HVAC system, the radiator transfers the heat to the air which is then distributed by the fans of the furnace when the thermostat comes on. All outdoor furnace systems are closed loop systems. This means that the cooled liquids return to the heat source via a return tube and are reheated again. Keep in mind the three types of outdoor furnaces that there are and choose the right one for your home and needs.