This document analyzes the causes of a discrepancy between expected electric costs of $19,460 annually based on full occupancy and usage, compared with a 1972 total billing of $49,819, and the fear of a 1974 $53,000 electric bill. A review was made of detailed proposals for 1967 and 1968 submitted to the building commettee to guide them in reaching a decision about selecting a hydronic system fueled with gas and oil or an all electric system at Mansfield Middle School in Spring Hill, Connecticut. The report explains how, in calculating the expected usage of fuel, certain inaccuracies crept into the equations and points up the value of making an economic comparison of alternate heating systems by estimating both the initial construction costs and the annual operating costs. Had the error in calculations been discovered earlier, the estimated costs between electric and hydronic systems would have reflected a $6,000 greater cost factor for the electic than for the hydronic system. It is hoped that the facts reported about this school will serve as a guide for school boards and building committees in their efforts to evaluate proposals for competing school comfort systems. (Author/MLF)