This paper presents the results of the scientific research "The Development of tariff regulation methodology and estimation of district heating liberalization effects”. The authors studied legislation of the price cap regulation on which the ‘No-MoreThan-Alternative-Boiler’ principle is based, constituting mechanisms of new economic relationships in the heating sector in Russia. The paper has studied the impact of the price cap regulation based on the ‘No-MoreThan-Alternative-Boiler’ principle established for the biggest unified heat supply companies operating in municipal areas where the heating market has completely transitioned to the new economic model as of the second half of 2021 (i.e. the transition period has ended). A lack of heat price explosion is noted; however, in 12 out of 15 unified heat supply companies studied, the conditions are in place for the consumer heating prices to rise faster than inflation in the next few years. According to the results of the research, the main problems of price cap regulation based on the ‘No-More-Than-Alternative-Boiler’ principle have been revealed, and practical recommendations for improving the mechanisms of ‘No-More-Than-Alternative-Boiler’ principle of the price regulation have been established.