These houses use passive energy sources such as light bulbs, computers, televisions and human heat. For example: one adult “heats” the interior with about 200 watts of power, and when you are in a household of four, or even better in a school where there are twenty children in a classroom, you can already tell.
Furthermore, in heat exchangers with heat recovery, the heat from the exhaled (polluted) air is transferred to the fresh cold air. So, at 20 °C indoors and 0 °C outdoors, fresh air can be heated up to 17-18 °C. For heating, because you have to heat up a bit in freezing weather, you will spend only CZK 5,000 a year instead of CZK 40,000.
In our country, passive houses are not yet so widespread, their construction is only in units of one percent. On the other hand, in Germany or Austria, they are much further away, with about ten percent of such houses already being built there.
The measurement is crucial. This is where air quality sensors come into play. The sensors make it easy and inexpensive to permanently measure indoor air quality, e.g. by monitoring the CO2 concentration in the air, and then control ventilation systems based on the values obtained to ensure good air quality while minimising energy consumption. Such systems are particularly useful for rooms with variable occupancy. Ventilation performance is then continuously varied depending on the number of people in the ventilated space. A high concentration of carbon dioxide induces breathing air, which in turn causes fatigue, drowsiness, reduced concentration, etc. This dramatically reduces the productivity of work in such a space.