A new need
Over-ventilated old constructionsAirtight new constructions To create a new ventilation flow in the new airtight construction
Done in the past in an uncontrolled way thanks to air leakage around the windows and through the walls, ventilation does not naturally take place anymore in the new constructions or after a thermal renovation unless an actual ventilation system is used.
In order to respect the new thermal and acoustic requirements for dwellings, new constructions and renovations are characterised by an envelop with reinforced insulation and sealing (2), whereas old constructions are generally "over-ventilated" (1) due to windows and outside walls with leak and poor insulation.
If the main thermal issues of old constructions have been solved (1), new problems have appeared. In new buildings and refurbishments, when ventilation is absent or insufficient, the new air cannot enter anymore, which generates directly visible problems: Air quality decreases (2) and the excess humidity condenses on the coldest part of the dwelling.
It is thus necessary to recreate openings to recreate an air circulation in housing: To overcome obstacles it is necessary to recreate a ventilation circuit:
- to place air inlets in habitable rooms to introduce air into the dwelling,
- to ensure air circulation inside the dwelling by leaving sufficient gap under interior doors,
- to place grilles or extract units connected to a vertical / horizontal duct or to a fan, in wet rooms (kitchen, bathroom and toilets). Those will ensure air extraction (air is able to enter by the habitable rooms only because it is extracted in wet rooms).