dertill
2018-10-15 22:30:02
- #1
For a Passive House standard – that is, without conventional heating, only with a ventilation system with additional supply air heating – there are no fixed required U-values. In contrast to all KfW efficiency house standards, a fixed value must be met here: a maximum heating load of 15 W/m² under design conditions (-10 to -16°C outside temperature depending on the region). All other standards from the Energy Saving Ordinance and KfW are solely based on the technical equipment, i.e., individual components, thermal bridges, and system technology.
The Passive House standard is also the only one with a solid physical basis, meaning that volume, orientation, and window areas are also decisive.
Due to the heat input through the room supply air, only a maximum of 15 W per m² of conditioned floor area can be additionally heated here at a maximum still comfortable air exchange rate and a maximum acceptable supply air temperature (I don’t know the exact values by heart right now). Otherwise, a warm water-based heating system would be needed, and it would no longer be a "Passive House."
The U-value of the floor slab plays a subordinate role above all without underfloor heating due to the equivalent U-value for earth-contact components (factor 0.4). Much more important is the reduction of thermal bridges, the glazed area and its orientation, the heat storage in the building to minimize load peaks, as well as location and volume. With intelligent planning, energy demand can be sustainably reduced here even without additional material use – also in non-Passive Houses.
The Passive House standard is also the only one with a solid physical basis, meaning that volume, orientation, and window areas are also decisive.
Due to the heat input through the room supply air, only a maximum of 15 W per m² of conditioned floor area can be additionally heated here at a maximum still comfortable air exchange rate and a maximum acceptable supply air temperature (I don’t know the exact values by heart right now). Otherwise, a warm water-based heating system would be needed, and it would no longer be a "Passive House."
The U-value of the floor slab plays a subordinate role above all without underfloor heating due to the equivalent U-value for earth-contact components (factor 0.4). Much more important is the reduction of thermal bridges, the glazed area and its orientation, the heat storage in the building to minimize load peaks, as well as location and volume. With intelligent planning, energy demand can be sustainably reduced here even without additional material use – also in non-Passive Houses.