Air infiltration
From Swikipedia
Introduction
Air infiltration is a term that describes the uncontrolled air movement through cracks, gaps and openings in the envelope of a building, driven by wind pressure and the stack effect. Air leakage (i.e. excessive infiltration) is a severe problem in buildings, where it is important to contain heat or cool inside the building. Infiltration can account for between 30 and 50 per cent of heat loss or gain in buildings with poor infiltration performance.
Infiltration is a term that relates to air leaking into or out of a home through small cracks in doors frames, window frames, outlets, walls, floors, roof, and other construction. It is a primary component of heat loss and is measured in Air Changes per Hour (ACH).
Brief Description
Common Points of Air Infiltration:
Wherever different materials meet, such as between wood siding and brick or between the chimney and the ceiling, there is the potential for gaps. Also, inspect the following areas for any cracks and gaps that could cause air leaks:
• Doors - both between the door and the jamb and between the jamb and the wall.
• Windows - both around the window frame and between the frame and the wall
• Mail chutes - around the mail chute, also make sure it closes tightly
• Any place where pipes or wires pass through a wall
• Around window air conditioners
• Light switches and electrical outlets, especially on exterior walls
Sealing Your Home for protection against Air Infiltration
Sealing air gaps will require different materials depending upon the application. Rubber gaskets are available for switches and electrical outlets and are installed beneath the cover plate. Caulking can be used to seal between different materials such as between stucco and wood siding. Caulking is also useful around exterior door and window casings and where pipes and wires pass through a wall. Sealing air leaks will make your home more comfortable and will result in lowered energy consumption for heating and cooling. Newer homes are built much more tightly than ever before and so much attention is paid to ensuring adequate ventilation. If you successfully seal your home, you must also implement a ventilation strategy. Indoor air pollutants can build to unhealthful levels and so proper ventilation must also provided. Furthermore, homes that burn natural gas, propane, fuel oil or wood must also make certain that adequate air supply is available for combustion so that a dangerous back draft condition does not pull combustion gases back into the home.
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