Air Leakage (AL)

Related terms

• Aluminum Window

  A strong, slim-profile metal-framed window; without a thermal break it conducts heat and is less efficient, so used mainly in warm climat…

• ADA Door Clearance

  Accessibility requirements for door width (32 in. clear minimum), maneuvering space, threshold height, and lever (not knob) hardware.

• Apron

  The trim piece applied to the wall beneath the interior window sill (stool), finishing the assembly.

• Argon / Krypton Fill

  Inert gas sealed between glass panes; denser than air, it slows heat transfer. Krypton outperforms argon in thinner triple-pane cavities.

• Astragal

  The vertical molding/seal where a pair of doors meets, closing the gap and providing a stop and weather seal.

• Awning Window

  A window hinged at the top that swings out from the bottom, shedding rain so it can stay open in light weather. Often used high on walls…

• Backer Rod & Sealant

  A foam rod set in the perimeter gap before exterior sealant, sizing the joint so the sealant performs and lasts.

• Balancer

  The spring or counterweight mechanism in a hung window that holds the sash open at any height. A common failure point in older windows.