The paper study the economy of improvements in the heating system and in a building in Lithuania and introduces the use of the cost of cold in heating calculations. A reduction in the cost of cold is the value of an increased indoor temperature. Supply water temperature control in the building eliminates the cold periods before and after the heating season. This reduces the cost of cold. Additional insulation both reduces the cost of cold and the cost of heat. Individual heat cost allocation reduces the cost of cold since every household can chose the temperature they are willing to pay for, if the heat transfer between the dwellings is compensated. The cost of cold is higher at the high price of heat ph = 45 EUR/MWh. Better economic data is necessary to draw definite conclusions about the economy.