Water in the form of gas. Water vapor is transported by air movement caused by pressure differences.

  Annual Fuel Utilization Efficiency

  The barrier that prevents infiltration of outdoor air into the conditioned space and exfiltration of indoor air to the outside. Also known as “pressure boundary”, it should be continuous and aligned [..]

  A hollow conduit or tube (square or round) that circulates air from a forced-air heating and/or cooling system to a room (supply duct) or returns air back to the main system from a room (return duct [..]

The process of sealing bypass ducts in the pressure boundary to prevent air leakage. Air sealing reduces heat flow from air movement and prevents water vapor from entering the wall.

Heat-resistant material used previously in many building products; represents serious health hazard as an airborne particulate.

  A construction method where the walls are framed before the floor is built, and the wall cavity is often open to both the attic and the basement.

  The framing ribbon between first and second floors of a structure.

 

  Structural element that is capable of withstanding load primarily by resisting bending.