Palladian window

Large, arch-top window flanked by smaller windows on each side.

 

Pane

Framed sheet of glass within a window or door frame.

 

Panel

Separate door panel or panels in a door frame. May be operable or fixed.

 

Parting stop

Narrow strip, either integral or applied, that holds a sash or panel in position in a window or door frame.

 

Picture window

Large, fixed (non-venting) window.

 

Precision Fit^® double-hung window

Fully assembled double-hung window that slides into the existing “pocket” when only your old window sash is removed. Trim, paint, wallpaper, plaster and siding are usually not disturbed. For use in replacement applications only.

 

Rail

Horizontal top or bottom part of a window sash or door panel.

  

Removable grilles

Grilles that can be detached and reattached to easily clean the glass.

 

Rolscreen^® retractable screen

Pella’s self-storing screen that rolls away and out of sight when not in use. Available on Pella^® Architect Series^® and Designer Series^® casement windows and sliding patio doors.

 

Rough opening

Framed opening in a wall into which a window or door is to be installed.

 

R-value

Resistance to thermal transfer or heat flow. Higher R-value numbers indicate greater insulating value. It is the inverse of the U-value (R=1/U).