The core heat for the house during most of the winter is my trusty coal stove. The stove is in a parabolic shaped opening in the large stone and concrete chimney. At first I painted the enclosure flat black figuring that the stone would get hot and continue to radiate heat, but after several years,where the stone got to 100-120F, I took the opposite approach. The parabola is covered with a reflective aluminum sheet which reflects the IR back to the stove so it runs hotter, and heats the air better since it reaches a higher temperature for the same fuel use. The aluminum air director can be lowered which increases the "chimney" effect of the rising heated air, and creates a natural draft to suck in cold basement floor air, and direct it into the upstairs. The air handler can also be turned on to force circulate the air through out the house. The air director open, lets much of the heated air flow into the basement ceiling area, to warm the floors and keep the basement at a higher temperature. Combustion air from outdoors is drawn from the same manifold as the wood stove.The automatic inlet air bimetal thermostat needed to be modified to allow inlet air to be drawn from the manifold and still allow proper thermostatic control.Two loops of stainless steel tubing pass through the firebox, to heat my domestic hot water all winter.