In the middle of January 1974, AAI Corporation received a contract to conduct a solar heating proof-of-concept experiment (POCE) for a public school building. On March 1, 1974, the experiment began as Timonium Elementary School, in Maryland, became the first school in the United States to be heated by solar energy. In this brief period, the corporation designed, manufactured, and installed a solar energy collector array complete with mounting trusses, a 15,000 gallon water storage tank, a hot water heating system, and instrumentation. From March 1 to May 15 the wing of the school chosen for the solar experiment received 90 percent of its heat from the solar heating system. Experimental data collected during this period is presented in this report. The report describes the system in detail, presents the analysis of operation, and discusses recommendations and conclusions based on the results of the experiment. The experiment is considered successful since it has proven that the solar heating of schools is possible, practical, and socially acceptable. In addition, over 1,200 gallons of fuel oil were saved in the brief period the system has been in operation. (Author/MLF)