Understanding Wood Window Parts

One of the biggest hurdles we have to overcome in our sales process is getting on the same page with customers when it comes to terminology. We certainly don’t expect any retail customer to be a window expert. That’s our job!

Unfortunately, there’s just no way around the technical side of what we do. Hey, if it were easy, everyone would be doing it! We admit the process can be tedious. Finding equal ground between what the customer can understand and what we need to know has, at times, been frustrating on both ends. We sweat the details, so the customer doesn’t have to.

We have no return policy for replacement sashes because our sales approach is simple: We won’t sell you a window unless we know its exactly what you need. We always have – and continue to – improve the buying experience for our customers. The incredible lack of talent for window repair has forced us to remain an online retailer. As our notoriety and reputation grow across the country, we continue to provide our customers with more useful and user-friendly content to make their buying experience as pleasant as possible.

Understanding the terms we use is no exception.

It’s fundamentally important to understand wood window parts and the terminology we use in sales conversations to build buyer’s confidence in not only our products but the people you are buying them from. We have put together a glossary of terms, along with some commentary, to help you better understand wood window parts and how we talk about them.


A sash is the glass and the frame holding the glass. The frame is not the sash by itself, nor is the glass. The “complete” sash is both the glass and the frame around it together. The sash is the operational panel. For example, on a casement window, the sash is what you crank out. On a double-hung window, the sash is what you slide up and down to open it.

Stile and Rail

These are parts of the sash. The stiles are the sides of the sash, and the rails are the top and bottom of the sash. Sashes can be constructed different ways. Most of the time, the stiles are shaped differently than the rails. We call the shape of a stile or rail: the “profile.” On casement windows, the stiles typically have a square or rounded edge, while the rails have a groove cut into the edge where the hinge is mounted. We call this the hinge pocket.

Some casement windows are built with the same profile all the way around. Some models will have matching stiles and rails where the profile is the same on all four sides. Double-hung sashes are built in much the same way with one exception: Double-hung sashes have a different rail called a meeting rail. Also referred to as a parting rail or check rail, these are the rails that “meet” in the middle when the window is closed.


A casement style window is on a hinge like a door and opens and closes by a crank handle. In terms of construction, other windows such as awning, hopper and transom windows are also considered “casement style” since they are made the same way. Casement windows can also be operable (also called “vented”) or stationary. Whether an operable or stationary model, a casement window is still built in the same manner. The exception is a direct set picture window or transom where there is no removable sash, but the glass panel is glued directly into the frame.


A double-hung window is a matched set of upper and lower sashes that slide up and down on a track with the help of spring balances. Wood windows are typically “double-hung” meaning both upper and lower sashes are operable. Vinyl windows are usually “single-hung,” meaning the upper sash is fixed, and only the lower sash is operable.


A slider window is similar in operation to a double-hung, but slides from side to side rather than up and down.

Double Pane Glass

Double pane glass is an encapsulated unit where two panes of glass are glued together, separated by a spacer bar. The spacer bar creates the overall thickness of the unit and forms the insulating air space. Double pane glass does not contain any gas and does not create a vacuum. The air space is merely dead air. One pane of glass can not be separated from the other to repair internal fog. Most of the time, the entire glass unit can be removed from the sash frame and replaced.

LowE Glass

LowE glass is the standard for modern times. LowE, or low emissivity, is a coating applied to the surface of the glass. It protects against UV rays and provides better insulating properties over just clear glass.

Argon Gas

Argon can be added to double pane glass units to replace the dead air inside the unit. While Argon does increase performance slightly, Argon is often added to help control sound.

High-Performance LowE Glass

High-performance lowE is a Fenster term to identify our better quality lowE product. Our standard lowE is a hard-coat, lowE product that is very typical of the window industry as a whole. Our HP-LowE is a soft-coat, lowE that is supplied in higher-end windows and commercial applications. Our HP-LowE is not recommended for small quantity orders.

Customers will not see the added benefits for a handful of windows. Fenster offers the HP product for customers upgrading their entire home, or at least the south or west, sunny sides of the house to get the most benefit of the upgrade.

Tempered Glass

Tempered safety glass is a building code requirement, not an upgrade, as many folks would think. Per universal building code standards, there are three common situations where tempered glass is required.

1.  Over or behind a tub or shower enclosure.

2.  In a stairwell.

3.  When windows are less than 18″ from the floor.

In some cases, the actual size of window will require tempered glass, but for our purposes, Fenster does not make a window large enough to meet this requirement. Check your local building codes for specific requirements in your area. Tempered glass is always labeled in one corner of the glass unit with an etched marking.


There are three types of grills that Fenster offers.

1.  GBGs (grills between the glass). Just as the name implies, GBGs are metal grills in between the panes of glass.

2.  SDLs (simulated divided lite) are surface applied grills glued to both the interior and exterior to mimic the look of traditional true divided lite panes of glass.

3.  Wood grill inserts are a wood-framed grill attached to the interior of the window by clips or pins.


Weatherstripping is the perimeter seal of a sash, also called the storm shield. The storm shield can be in fin or bulb form to reduce the amount of wind-driven rain, air and debris from around the sash.  The storm shield is not designed to be a thermal seal. The weatherstripping around the jamb of the window is typically in bulb form. This seal is the thermal seal blocking air from entering around the sash.


Cladding is the metal or vinyl skin on the exterior side of any sash that is not painted on the exterior.


Jambliners or balance kits are a very common repair item for double-hung windows. Jambliners consist of the vinyl tracks the sashes slide up and down on and the balances or springs that provide tension on the sashes to hold them in an open position. The biggest thing to know about jambliners is they are not brand specific; instead, they are very universal across the window industry.

The industry as a whole adopted set standards for jambliners throughout the ’80s and ’90s to simplify the supply chain. Regardless of the brand (generally speaking, of course), if you have a wood window with compression fit jambliners that allow the sashes to tilt in by simply applying pressure to the tracks and pulling the sash in toward you, then the following is true:

1. White and beige were the only standard colors.

2.  There are two track shapes to fit the edge shape of the sash, square plough or “Vee” plough.

3.  A universal sizing chart was established for new construction windows where nearly every manufacturer made their windows to fit this sizing chart.


By definition, hardware should be self-explanatory.  Basically, hardware would refer to any window component that is not wood, glass, cladding or weatherstripping. We included this on the list to make an important point. Much like jambliners, hardware is not brand specific unless you have Pella, Andersen or Marvin, which are brands we don’t represent. For everyone else, the industry-standard was TRUTH brand hardware.

Caradco is our biggest selling brand, so we get a ton of requests for “Caradco” hardware. There’s no such thing. Caradco used TRUTH, just like 99% of all other window manufacturers. When shopping for replacement hardware, your search should be based on matching the part and identifying that part by its function, and not searching for your specific brand of window. The reverse of this is also true.  We, nor anyone else for that matter, can tell you what part you need based on your brand of window.


We hope this glossary is helpful to you as you decide to repair or replace your wood windows. If you have any questions, please click here to contact us.


  • Posted February 28, 2020 at 1:41 pm | Permalink

    You covered a lot of aspects in this article. I think some of our clients could benefit from a good, clear explanation like this. Thanks for sharing!

  • Posted April 26, 2020 at 3:26 pm | Permalink

    It’s hard now days to find a good information about wood window parts, you really nailed it.
    Great article !

  • Posted August 11, 2020 at 8:04 pm | Permalink

    Great post!Thank you for sharing your knowledge with us!

  • Posted August 20, 2020 at 5:19 pm | Permalink

    I like that you explained everything in detail. Thanks for the tips!

  • Posted August 24, 2020 at 8:07 am | Permalink

    I like how you included info on jambliners. Lots of people aren’t even aware of what those are!

  • Posted August 25, 2020 at 2:35 pm | Permalink

    I like that you explained everything in detail. Thanks!

  • Posted August 28, 2020 at 7:46 pm | Permalink

    Thanks for the detailed explanation. This is a very good post. Thanks for sharing!

  • Posted September 2, 2020 at 5:49 pm | Permalink

    I like that you explained everything in detail. Thanks for sharing!

  • Posted September 12, 2020 at 8:23 pm | Permalink

    I like the layout of your site. Thanks for covering such an underrated topic!

  • Posted October 18, 2020 at 7:01 pm | Permalink

    You have a very informative site with a lot of great content!

  • Posted November 19, 2020 at 7:19 am | Permalink

    This article tells you about the understanding wood windows parts. Such articles are not only knowledge enhancers but also very interesting to read and to learn to compare from.

  • Posted February 4, 2021 at 3:31 pm | Permalink

    Great content! thank you for sharing

  • Posted February 9, 2021 at 5:30 pm | Permalink

    thank you for sharing. this is a great post

  • Posted February 15, 2021 at 3:28 am | Permalink

    Very topical content! Thanks for the info!

  • Posted March 14, 2021 at 6:10 pm | Permalink

    Great content! Thanks so much for sharing!

  • Posted March 14, 2021 at 11:18 pm | Permalink

    Thank you so much for the great tips and advice!

  • Posted June 12, 2021 at 11:32 am | Permalink

    Thank you for sharing this information. concrete patio installation

  • Posted June 25, 2021 at 1:45 pm | Permalink

    Hello I need a new medal hook that in on the side of my sash which fits into the jamliner. is there name for this ? Also where can i find this item? Thanks

    • Posted June 28, 2021 at 4:44 pm | Permalink

      Nancy, Any jambliner hardware we offer would be included in a jambliner kit. We don’t sell specific individual parts like what you are looking for. You’d have to a fairly comprehensive search for window hardware for something like that, but there are several window hardware companies online that might have what you are looking for.

Post a Comment

Your email is kept private. Required fields are marked *