Universelle Energiekennzahlen für Deutschland [Teil 3]

Universal energy ratings for Germany, Part 3: specific energy consumption for central water heating and the relation to heating energy consumption.

The universal energy ratings for Germany include about a quarter of a million energy consumption figures for buildings recorded by the BRUNATA-METRONA Group over the last six years. In previous analyses the consumption for space heating and central hot water heating have been combined. Now figures have been broken down to show the energy consumption for central water heating, reflecting its increasing significance to overall energy consumption in the context of the general improvements in renovation levels and the increased energy efficiency of residential buildings.
The typical absolute energy consumption for water heating is reduced from buildings with low energy efficiency levels to very energy-efficient buildings by more than half, i.e. around 40 kWh m^-2a^-1compared with around 15 kWh m^-2a^-1(median values), while the relative proportion of the energy consumption used for water heating rises from 15 % to 35 %, more than double. The finding that water heating in well thermally-insulated buildings can represent a third of the heating energy consumption, and in future may rise to as much as half, underlines the necessity of determining the amount of hot water according to use, giving a breakdown of energy costs that is as accurate as possible and precisely differentiating water heating from space heat ing for energy analysis purposes. In addition, an applied mathematics method is proposed for the automated compilation of figures for any desired body of data.