Ventilation: a central role in the individual housing

Managing to control air quality has become a major concern of our modern lives. Ventilation poses energy, health and building preservation issues. The evolution of the buildings towards even more airtightness exacerbates its central role. State of systems and regulations.

Housing, office, transport... If we spend an average of 80% of our time in enclosed places, the air we breathe is not al-ways the healthiest.

The Observation of the Quality of indoor air, in particular, shows that this air can be up to ten times more polluted than fresh air.

In this context, special attention should be paid to the ventilation of the buildings. By bringing fresh air in and getting polluted air out, chemical and biological pollutants are eliminated while avoiding mould development. Improving the comfort of residents and protecting their health thus go hand in hand with the preservation of the building.

In the context of the Grenelle Environment Forum, designing high-performance buildings implies airtightness and increas-ingly reinforced outdoor insulation.

This is good news in the effort to limit heat loss, since ventilation through air leakage is eliminated; however, this leads to increasingly control air flow. Professionals aim to design systems to maintain sufficient air renewal rates to ensure good indoor air quality, while controlling energy costs related to the heating and cooling of fresh air.

In France, respect of thermal regulations (RT 2012* applicable to housing since January 1st 2013) doubles in respect for the regulations of hygienic air renewal rates.

The constant flow to rate modulation

The main regulatory document regarding this question is the March 24 1982 decree. It maintains the principle of general and permanent ventilation prescribed by the October 22 1969 decree. It also sets requirements of minimum air rate extract in operating parts and allows rate modulation. The change made by the October 28 1983 decree, which specifies that the modulation of air renewal can be carried out by a mechanical device, in particular, made the hydro adjustable system development possible (the rate is modulated according to humidity levels inside and outside) more energetically powerful than the self-adjusting system, at constant rate. The scan ventilation principle is set in motion: fresh air entries and contaminated air exits are located in separate parts. Air transfer is then ensured through clearing the airways or through transfer grids, through extraction or through insufflation. Double flow systems, on the other hand, are increas-ingly used, even if they are more expensive. They implement a heat exchanger for treating and preheating incoming air and allowing to modulate rates based on current needs. The energy profit of the double flow compared to the single flow with a fixed rate in a single house is estimated between 1 and 5 kWep/m2.an, meaning 5 to 10% of the total Pec (primary energy consumption).

To ventilate according to the rules

If, strictly speaking, there is no "Ventilation" qualification, the professionals dealing with this – usually climate engineering companies – must refer to the new UTD 68.3 published in 2013 and enact the rules for mechanical ventilation installa-tions in residential establishments. Good practices also gathered in the "Rage" documents published by the CSTB** and all the more important, as they make it possible to ensure an effective maintenance afterwards.

The future of ventilation also depends on taking renewable energy more and more into account. Indeed, there are thermo-dynamic water heaters recovering energy from the outside air to produce hot water through a heat pump, or even heat recovery systems under photovoltaic solar panels.