Passive House is not an energy standard, but an integrated concept ensuring the highest level of comfort. The exact definition is as follows:
"Passive House is a building whose thermal comfort (ISO 7730) can be achieved only by postheating or aftercooling of fresh air mass, which is necessary to achieve sufficient indoor air quality conditions – without the need for additional air recirculation."
This is a purely functional definition that does not contain numeric values and is valid for all climates. The Passive House concept was not "invented" by anyone – in fact, the principle of Passive House was discovered. Thermal comfort is achieved through passive measures (insulation, heat recovery, passive use of solar energy and internal heat sources).
The following considerations help you better understand this concept:
- All airtight buildings (any low-energy building needs to be airtight), except those in so-called moderate climates, require the use of an efficient ventilation system. In Passive Houses this system can also be used for heating purposes, without the need for additional systems, main technical interfaces, auxiliary fans etc.
- This concept allows the construction of houses equipped with a highly efficient heat recovery system at a very affordable price which is usually difficult to do, since the ventilation system costs as much as a heating system – a investment that for a couple hardly pays off. As such, it is chosen to cut into one of the two systems: or in the ventilation system, installing only one exhaust system (in this case, the building will become a low-energy house with conventional heating) or in the heating system using the system of ventilation to heat up too – in this case, the building will become a Passive House.
This heating concept automatically implies extremely low energy consumption.
We must not forget an excellent insulation of the surrounding building – especially in cold climates to keep the desired heat inside the building, but also in warm climates to keep the undesirable heat out of it.
The calculation of the energy balance will help determine the level of insulation that will be required in a given building and climate.