The Passivhaus certification is primarily focused on energy efficiency by minimizing heating and cooling demand. To achieve this, it follows 5 basic principles in design and execution, one of which is mechanical ventilation with heat recovery.

In this case, not only is the building certified, but, for example, in the case of ventilation, Passivhaus also certifies heat recovery units. At Siber, we have the vast majority of Passivhaus-certified recovery units, which ensures that a Siber ventilation system with heat recovery, when well designed, guarantees compliance with ventilation requirements under Passivhaus certification.

Considering the needs of a Passivhaus building, we can group the advantages of a ventilation system into four main areas:

1. The ventilation system must be designed to renew the air 0.3 times per hour inside the building, ensuring:

• Constant indoor air renewal.
• Absence of odors.
• Regulation of VOCs and elimination of contaminated air particles generated indoors.

2. The air entering the home must be filtered. Passivhaus requires at least F7 filters for air supply.

3. A well-designed ventilation system requires zoning, extracting stale air from wet rooms or areas with higher levels of odors, humidity, and other emissions, and supplying clean, filtered air to dry rooms.

1. One of the great advantages of a mechanical ventilation system is that it eliminates the need to open windows for ventilation (even though they should still be operable), which allows isolation from external noise.

2. On the other hand, the heat recovery unit is already silent, but to ensure that the entire ventilation system does not exceed the maximum allowed noise levels, the following must be considered:

- Use of silencers to avoid transmitting possible noise from the ventilation unit to the rooms.
- Use of acoustic attenuators before each outlet if the system is tree-type, to prevent noise from passing between rooms via the supply or extraction vents.
- Use of silencers in distribution boxes if it is a star system.
- Proper design to ensure air speed inside the duct does not exceed 2 m/s.
- Adjusting airflow in the design so that, with the correct supply or extraction outlets, noise does not exceed 25 dB per outlet.

1. The user can regulate ventilation based on the needs of the home at any given time, adjusting indoor CO2 and humidity levels. There are also humidity and CO2 sensors available for more precise and regulated control.

2. Since there is no need to open windows for ventilation, air drafts inside the home are avoided, increasing indoor comfort.

3. The ventilation unit has a bypass system for summer nights, to take advantage of cooler outdoor air without passing through the heat exchanger.

1. The heat recovery unit must have an efficiency above 75%, which greatly reduces heating demand in winter and cooling demand in summer.

2. The ventilation unit must be low consumption, meaning CO2 emissions from its use will be minimal. Power consumption should be based on flow and pressure drop (good value: < 50 W at 150m³/h and 50 Pa, 0.45 W/(m³h)).