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Three conserver agroecosystems emphasizing food self-sufficiency (a rural mountain homestead, a retrofitted suburban homesite, and a semiarid desert homestead) were selected for energy analysis. Energy diagrams were used to detail flows of renewable natural energy (sun and rain), fossil-fuel-based inputs, and food production. Energy inputs were considered in terms of equal work potential to permit comparisons of ratios between the relative contributions of natural and fuel-based inputs. Food production was expressed in a newly defined unit of equal nutritive value, the “nutritional equivalent kilocalorie”, based on the food’s protein quantity and quality and its caloric content. Energy ratios and indices were calculated, relating energy inputs, food production, and number of people supported. System inhabitants were found to observe a conserver lifestyle, consuming 12.5 to 25% as much total energy as the average United States inhabitant. Efficiency of food output per fossil fuel input on these homesteads is equal to or greater than that of the United States of America food system as a whole.