Discussion on storing heat waste from milk cooling with the use of heat accumulator using a phase transition was presented. It was assumed that the stored heat would then be next used for preparation of domestic hot water or in the central heating installation. The use of heat waste from technological processes influences decreases fuels consumption, which next influences the improvement of condition of the natural environment by decrease of CO2 emission to atmosphere. Heat waste from the process of milk cooling constitutes a significant source of thermal energy in the energy balance of farms, where diary cattle is bred. Performed calculations show that accumulated daily amount of heat from milk obtained from 100 cows is sufficient to heat approx. 1100 dm3 of water from 10 to 55ºC for domestic purpose or for heating approx. 1650 dm 3 of water from 10 to 40ºC, e.g. for floor heating which will satisfy top central heating demand of a house of usable area of approx. 120 m 2.