Air Tightness &NaturalVentilation. The effect ofbuildingmore air tight is, that we are left with comparatively little air infiltration, even if backgroundventilators(tricklevents) are used correctly.
The ALIVE project assessed how wellnaturalventilationcan reduce energy use and prevent overheating in energy-efficientbuildings, while still maintaining acceptable IAQ.
4.Airtightnessandventilation.But anyairtightnessexpert will knock big holes in this argument. “Number one, leakage doesn’t give youventilation,” says Niall Crossan of EcologicalBuildingSystems.
This study has shown the significant effect of thebuildingairtightnessandthenaturaldriving forces, mainly the wind effect, on the performance of a decentralized mechanical exhaustventilationsystem with a constant airflow rate in a typical social house in Chile.
AirtightnessandVentilation: A Delicate Balance. Achieving a high level ofairtightnesssignificantly reduces air leakage, optimizing energy efficiency and minimizing heat loss or gain.
NaturalVentilation:NaturalVentilationrelies onnaturalforces (wind and buoy-ancy) and passive devices like wallventsor tricklevents, without continuous oper-ating mechanical fans in wet rooms.
Likenaturalventilation, infiltration and exfiltration are driven bynaturaland/or artificial pressure differences. These forces are discussed in detail in the section on Driving Mechanisms forVentilationand Infiltration.
Naturalventilationuses wind and temperature differences to move fresh outdoor air indoors through openings (windows, doors,vents). As such,ventilationrates vary depending on weather and how often occupants open/close windows or doors.
Mandatingairtightnessinbuildings, in the range of the passive house requirements, along with effectiveventilationsystems such as heat recoveryventilation, will help protectbuildingowners from potential envelope issues and higher energy bills.
