Previous issues of FARM SHOW have featured new-style heating systems built outside the home. Latest new development along this line is the "build-it-yourself" HAHSA (Heating and Heat Storage Apparatus). The wood-burner is housed in a small shed, detached from the house or other structure it heats, and has 18 tons of sand packed around the burning chamber for heat storage.

In the sand and above the fire chamber are two heat exchangers. One is connected by two 1-in. pipes to carry hot water to the building to be heated, and return cold water for reheating. The system also heats water for domestic use -- using 1/2-in. pipes and the second heat exchanger.

The manufacturer claims the HAHSA system is especially safe because the fire is outside, away from the house or other building. There are no trapped gases in the home, no chimney fires, and no wood-burning mess in the house.

Heat from the HAHSA is thermostatically controlled, keeping the building heated as desired. Also, the unit can be fired with almost anything that will burn, such as wood, lumber scraps, waste paper or cardboard. With 18 tons of sand to store heat, the furnace needs to be fired up only once every day or two.

The manufacturer claims the system will pay for itself in 12 to 18 months.