Ventilation: a central role in 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 buildings towards even more airtightness increases the importance of ventilation.

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 always the healthiest.

The Observation of the quality of indoor air 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 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 requires airtightness and 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 restricted 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, compliance with thermal regulations (RT 2012 applicable to homes since 1 January 2013) is coupled with compliance with regulations on hygienic air renewal rates.

From 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 wet rooms and permits rate modulation. Subsequent changes made by the October 28 1983 decree allowing the modulation of air renewal by a mechanical device permitted development of the hydro adjustable system (where the rate is modulated according to humidity levels inside and outside) which improves efficiency. Fresh air entries and contaminated air exits are located in separate zones. Air transfer is then ensured through airways or transfer grids, using extraction or insufflation.

Double flow or heat recovery systems, on the other hand, are increasingly used although they are more expensive. They integrate a heat exchanger to preheat incoming air and modulate. Double flow systems can generate between 1 and 5 kWep/m2 /year energy improvement compared to single flow systems, which translates into 5 to 10% of the total Pec (primary energy consumption).

Ventilation best practice

Although there is no "Ventilation" qualification, professionals – usually climate engineering companies – must refer to the new UTD 68.3 published in 2013. Best practice is summarised in the "Rage" documents published by the CSTB**.

Renewable energy will become increasing important in ventilation. Solutions include thermo-dynamic water heaters recovering energy from outside air to produce hot water through a heat pump, and heat recovery systems under photovoltaic solar panels."