Initially approximately 80 flats of Vivawest GmbH in Reulstraße were connected to the district heat supply. The changeover of the heat supply of these buildings was completed by the beginning of the heating period 2011 / 12. A further 80 Vivawest flats in Kantstraße/Leibnizstraße are connected to the district heat supply in the following year. The CO2 reduction amounts, in the case of the changeover of the buildings with a heat output of 1,000 kW of low-tariff night-time electricity, to about 525 t/a and in the case of the changeover of the remaining units with 2,000 kW of mixed heating (gas, oil, electricity) to about 300 t/a. Hence about 825 t/a of CO2 is saved