Nowadays the majority of the companies stocking services of central heats face to the necessity to modernize the sources of the heat generation. In this Master’s Work there are analysing “Radviliškio šiluma” companies feeding the heat, boiler – houses in Radviliškis, the opportunities of the investments in order to reduce the prime cost of feeding the heat in their heat system. There are analyzing these alternatives: the basic variant, the peat burning, the cogeneration installing, and the optimization of the individual parts of the pipeline in the heat system. All alternatives are compared using the method of the proximity to the ideal point. In order to appraise the results there was used the computer tool energyPRO. This computer tool summed up the constant and permanent inputs, the inputs of the system’s service, the inputs of the waste, and the costs of the environmental pollution and the prime cost of the heat energy. There was estimated the way of the optimal heat feeding – the cogeneration installing - comparing the significance of the criteria of the evaluation. The method of the proximity to the ideal point could be used in comparison of other alternatives and criteria of the evaluation.