In order to achieve a reduction of the energy consumption in the build environment (30% in 2020) it is a necessity to reduce the consumption of the existing building stock. For social housing (30 %) this has to be done under the condition that the total cost of living (rental+ energy costs) for the tenants cannot be increased. In the project HEER (High Energy Efficient Renovation) a plan has been developed that should reduce the energy consumption for heating to 1/10 of the current consumption. Although passive house quality cannot be reached, the same measures have been applied: increased insulation, triple glazing, heat recovery and an airtight building envelop. Over an extended life span of thirty years the costs have to be recovered by a raising the rent. For the tenants the increased rent should be compensated by the reduction of the energy costs. The housing company wants to guarantee this. A robust performing heating and ventilation has to be implemented. This paper describes the alternate solutions for the adaptation of the heating and ventilation system and a performance test in two renovated dwellings. Typical passive house solutions are not applicable; currently over 90% of the dwellings use natural gas for heating and hot water production and this will be the preferred choice. Different solutions are discussed. For terrace house small collective system do have advantages in maintenance and utilization of solar thermal systems. The extra distribution losses can be compensated by the increased efficiency. Solutions for individual dwellings show a mismatch in capacity for heating and hot water production. The maximum heat demand is well below the min. capacity of today’s available condensing boilers. Through simulation and experimental setup different solutions are evaluated. The field test showed that the auxiliary electricity is no longer negligible and has to be taken into account when evaluating different solutions.