In order to determine whether it is possible to reduce energy use for domestic hot water (DHW) production and distribution, without increasing the risk of Legionella spp. development in sanitary installations, a full-scale test facility was built, consisting of a 200 liters water tank, a circulation system of nearly 40 metres long and 2 draw-off pipes. On a daily basis, a consumption profile corresponding to the DHW use of a single family (4 persons) was applied separately using two tap pipes, one corresponding to a kitchen and the other to a bathroom. Legionella spp. was cultivated in a separate water tank and then introduced into the test facility. The DHW production temperature was kept at 45°C with a periodical heating to 60°C for different durations and different frequencies. Legionella spp. concentrations were measured, both in the water and in the biofilm. The influence of different parameters was studied: disinfection of the sampling taps, flow rate of sampling, disinfection of the circulation system only or in combination with the draw-off pipes.