Short answer. A-Series casement and awning sash weatherstripping is not one stable location map across all years. Andersen describes leaf weatherstrip around all four sash sides on units made 2008–2011; for 2011–present it describes leaf weatherstrip at the top horizontal sash edge and bulb weatherstrip on both vertical sides. The year 2011 is shared in the descriptions, so a unit identified only as “2011” needs manufacturer confirmation rather than an assumed exact switchover date. [S:ANDA]
Use location, date and product family together
| Evidence observed | 2008–2011 documentation | 2011–present documentation |
|---|---|---|
| Leaf on upper edge | Part of four-edge layout | Top horizontal edge |
| Leaf on vertical edges | Described on four sides | Not the described later vertical-side seal |
| Bulb on left/right edges | Do not infer it as the historic standard layout | Described on both vertical sash sides |
| Unknown year | Preserve uncertainty | Preserve uncertainty |
The overlap year is an editorial caution. An identification label, order record, or Andersen series/date verification is stronger evidence than the shape of a loose profile. Do not conclude that a later bulb can replace an earlier leaf simply because its barbed leg resembles the old mounting leg.
Made-to-order is not the same as cut-to-fit
Andersen calls the A-Series leaf weatherstrip a size-specific made-to-order item. Its replacement bulb is described as cut-to-fit and offered in Grey, White or Canvas. [S:ANDA] These are different ordering processes, not instructions to buy generic foam tubing by nominal diameter. A purchased piece still needs the correct product series, placement and installation interface confirmed.
For a request to a dealer, distinguish the window sash outside measurement from seal order specification. A casual tape measurement alone may not correspond to the unit size Andersen uses for an ordered leaf. Collect exact manufacturer identifiers and let the original parts channel tell you the order size.
Photograph without dismantling the window
Photograph the whole casement or awning sash, with a view showing the hinge side and interior side. Record the location of the original leaf or bulb at each edge, especially the top and both vertical stiles. Sketch where the old strip exits its channel; do not cut the mounting leg to “test” a substitute. Record any label and approximate installation era but identify the source of that date. If the sash must be removed for a documented procedure, first identify its operator: the Andersen source points to distinct sash-removal guides for split-arm casements, straight-arm casements and awnings. [S:ANDA]
Questions for Andersen before ordering
- Is the unit's manufacture date, not just installation year, known? Which side of any 2011 design revision applies?
- Which perimeter edges on this exact unit call for leaf and which for bulb?
- What unit size and color are required for a replacement made-to-order leaf?
- Does the selected bulb come with a verified channel/mounting interface and cut-length instructions for this sash?
- Can this homeowner safely support the sash during removal, or should a service provider handle it?
Stop conditions: a damaged sash support, uncertain operator type, inaccessible exterior opening, or binding sash calls for support from an appropriate service professional. A no-confirmed-fit outcome is meaningful: do not order solely from a profile silhouette.
Original manufacturer evidence
Andersen Help Center 000002428, Replace Window Sash Weatherstrip for A-Series Awning and Casement Windows, sections types, order parts and installation. Read 2026-10-12: manufacturer page. Edition is a live web article (no fixed PDF edition supplied); date cutover at the 2011 boundary requires individual-unit proof. Distinct from accepted NW0011, which primarily compares 100 vs A-Series.