Sizes which are used at designing garden facilities with the use of heat pumps were discussed in the paper. Based on the analysis which was carried out, the scope of changes of effective coefficient of heat penetration through the facility cover and regression equation, which in a given scope allows calculation of its value, were determined. Based on the previously determined effectiveness of the installed heat pump (COP) also the required heating power of the heat pump was determined. This power depends on both environmental conditions (inside and outside the facility) as well as the percentage satisfaction of demand for the required heat power by the heat pump. The required number of 100 m boreholes, where ground vertical heat exchangers type 1xU and 2xU will be installed was also determined. Moreover, it was found that as a result of the use of standard relations in the developed nomogram, which describe energy issues in the heated facility, the developed relations have both cognitive as well as application values. Therefore, they may be used in all garden facilities, where the analysed cover was used and by generalization in these objects, where the value of heat penetration coefficient and the area of the facility are known.