At architectural studio Apxe, we design controlled ventilation as a core system for fresh air and comfort in a Passive House. We supply filtered fresh air to living rooms and bedrooms, and extract stale air from kitchens, bathrooms, toilets and laundry rooms. This gives people a continuous supply of fresh air where they spend their time and removes moisture and odours from utility and sanitary rooms.
Fresh air and moisture extraction
Principle scheme of a passive house ventilation system, architectural studio Apxe
The ventilation system moves air along carefully planned routes. We supply fresh air to the habitable rooms and direct it towards the rooms where we extract it. To maintain this airflow, we also design transfer routes between rooms, such as door undercuts or transfer grilles.
Scheme: Controlled ventilation system of passive house Waterhouse, Blagoevgrad
In the laundry room, we provide sufficient extraction to remove the moisture that clothes release as they dry on a line. This keeps the air moving and prevents excess moisture from building up in the room.
The heat recovery unit: the heart of the system
The heat recovery unit transfers much of the heat from the exhaust air to the fresh air entering the building. This lets us ventilate continuously without losing all that heat outdoors during colder months.
We choose heat recovery units that the Passivhaus Institut (PHI) certifies for Passive House buildings. From those, we select some of the best solutions on the market for each project. We see the heat recovery unit as the heart of the ventilation system, and its quality directly affects the system’s efficiency and performance.
The system remains easy to use every day. You can replace the filters easily without complex servicing. The filters cost little compared with the benefits of regular replacement. We follow the manufacturer’s recommendations for routine replacement and maintenance.
We design air supply and heating as one solution
During design, we calculate the temperature of the air we will supply to each room and how much of the heating load the ventilation air can carry. We then determine which additional heating or cooling systems the building needs and how to coordinate them with the ventilation system.
This work takes experience and detailed design. We do not rely on a general assumption that ventilation alone will heat or cool the building. We analyse the specific energy model, airflow rates, supply air temperature and the needs of each room.
We choose grilles that support comfort
We select high-quality air grilles and diffusers that direct the air stream along the ceiling. We use the Coandă effect to distribute supply air evenly through the room and reduce the sensation of draughts. During system commissioning, we adjust the airflow at every grille to achieve the planned ventilation rate.
You can still open the windows
The ventilation system does not prevent you from opening the windows. You can open them whenever you like. On mild spring and autumn days, natural ventilation can complement the system. In summer, night-time ventilation can help remove accumulated heat.
At architectural studio APXE, we coordinate ventilation with airtightness, the energy model, and the heating and cooling systems. This allows us to design a complete solution that supplies fresh air, removes moisture and odours, and supports comfort throughout the building.
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| Heat exchanger with 86% heat recovery, Plus-energy house in Kladnica | |
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| Ventilation ducts from the ventilation system of Plus-energy house, Kladnica | Ventilation ducts with silencers as part of the ventilation system of the building |
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| Ventilation grille for supply air in the premises | Air transfer grille embedded in a door necessary for providing proper air exchange |
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| Conducting commissioning of ventilation system | Precise adjustment of each ventilation grille’s air-exchange during the commissioning |
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| Heat exchanger’s filters replacement | Heat exchanger’s filters replacement |