Good-sounding concepts are Low-energy and Passive houses, but it is not always clear to non-professionals what exactly is behind them. According to European legislation, all newly built buildings after 2020. they must have a net energy consumption for heating close to zero, not using energy from minerals. So let’s clarify what is behind these concepts.

According to the Passive House Institute, the criteria for a Passive House are:
Energy consumption for heating and cooling per year is up to 15 kWh per square meter of usable area of ​​the building;
The energy for heating, ventilation, hot water and household appliances and lighting is up to 120 kWh per square meter of the usable area of ​​the building;
Air tightness;
Temperature comfort – the hours of the year in which the average room temperature exceeds 25 ° C should not be more than 10%.
These criteria can be achieved through a well-thought-out design that includes:

Minimum thermal bridges in the structure;
High quality windows;
Ventilation / heat exchange system;
Quality thermal insulation;
Airtight construction.
According to the law of conservation of energy, the sum of all heat losses must be equal to the sum of all heat gains. Therefore, ventilation losses and heat transfer losses, which cannot be covered by solar and internal heat gains, must be covered by a heating system or provided by the energy released during living in the dwelling (human heat, cooking, lighting, electrical appliances, etc. .) and from the accumulation of sunshine (good exposure, solar installations), which for the Passive House are limited to 15 kWh / m² per year.

In order to reduce the heat and energy losses of the house, attention is paid to a number of other factors such as ambient temperature, available renewable energy sources, the area and color of the external surface of the building, the area of ​​windows and doors, lighting. As many methods and materials as possible are used, which aim to optimize losses, while ensuring an optimal microclimate and comfort for the occupants. All elements of the house, even the small details, are considered and designed first in a virtual environment, and the information about the whole project is connected in a common database, which allows to find the optimal solutions for a specific situation.