8111 Tryon Woods Dr #205
Cary, NC 27518

Windows & Doors 101

Many people, especially homeowners, often only buy windows and doors once in a lifetime and can often find navigating their way through this process confusing. The Window Works Co. wants to make this process as easy as possible and here at our Windows & Doors 101 we offer a glossary of terms that will help explain the different window and door styles and the components that make up these products. Window Works also includes many of the terms for the miscellaneous parts and pieces used in producing and installing these products. One of our many goals at Window Works is to make your project as easy and enjoyable as possible.

Windows Styles

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    • Double Hung Windows – Often referred to as up and down windows. These windows operate with both the upper and lower sashes moving vertically. They also can tilt in for easy cleaning.
    • Single Hung Windows – This is an up and down window where only the lower sash operates vertically. The upper sash is permanently fixed and does not move.
    • Casement Windows – Often referred to as crank out windows. These windows use a crank handle and mechanism to open outward and are hinged right or left or can be stationary. Multi operating units have posts between the window sashes.
    • French Casement – Similar to a regular casement, French Casements are double casement units with no post between the window sashes, hinged right and left. When opened it is a clear unobstructed opening.
    • Push Out Casement – Same as a casement window but lacks the operating hardware. On this window you just push it out to open. This window is more of a traditional European style.
    • Sliding Windows – Window with one or two sashes that slide horizontally.
    • Awning Windows – Window with crank handle and mechanism where the window sash is hinged at the top and the window opens upward.
    • Hopper Windows – Window cranks open and is hinged at the bottom of the sash. The window opens by tilting inwards.
    • Tilt & Turn Windows – Tilt & Turn windows open two ways. The sash swings inwards. The window can also be opened by tilting the top inwards, hence the name, Tilt & Turn. The change in operating direction is controlled through the handle and hardware.
    • Picture Windows – Fixed lite, non-venting window.
    • Bow Windows – All window units (3 or more) are on an existing equal radius, i.e. they bow out circularly.
    • Bay Window – Center window/s and has side flankers that are set at 30, 45 or 90 degrees.
    • Garden Windows – Window is 90 degrees with a glass front, sides and top allowing maximum sunlight. It is usually accompanied with a shelving unit.
    • Arch Top – Window with arched tops and equal legs.
    • Circle Top – Half circle window, usually placed above other window units.
    • Elliptical Top – Similar to circle top but elliptical in shape.
    • Specialty Windows – Any number of windows of unusual shapes, polygons, pentagons, trapezoids, etc.
    • Sky/Roof Window — Roof mounted window, either fixed or venting.
    • Solar Tube – Roof mounted window with tube and light diffuser to bring in more natural light even at night and allows for a reduction in artificial light sources.
    • Storm Windows – Thin frame windows designed to mount on top of existing windows so as to help achieve greater energy efficiency. Most modern windows today do not need to utilize storm windows as they are able to obtain much higher levels of energy efficiency compared to less technologically advanced windows of the past.

    Types of Window Installation

    • New Construction/Full Frame Replacement Windows – Entirely new window is installed including new frame.
    • Insert Windows – These windows are replacement windows and are made to fit into the existing window frame.
    • Vinyl Windows – Window is made entirely of vinyl (Polyvinyl chloride, also known as PVC).
    • Wood Windows – Windows made entirely of wood and has exposed wood on both the interior and exterior of the unit.
    • Clad Windows – Wood window where the exterior is covered and sealed in a particular material, usually vinyl, aluminum or fiberglass. This protects the wood from the elements and makes it virtually maintenance free.
    • Sash Kits – Replacement option for double hung windows. Kit includes upper sash, lower sash and jamb liners. They are designed to fit into existing window frames and are similar to insert windows but generally providing for an easier installation process.


    • Entry Doors – Doors used for entranceways, such as front doors, side doors, garage entrance doors, rear entrance doors, etc.
    • Hinged Patio Doors – Inswing or outswing hinged doors that are most utilized to gain access to patios, decks, etc.
    • French Wood Style Doors – Hinged patio doors with a Frenchwood profile. This profile usually has a bottom door rail of about 8”.
    • Gliding Patio Doors – Doors that operating by sliding horizontally. These doors can come in several different profiles including a Frenchwood style.
    • Fire Rated Doors – Doors that are designed to be fire resistant up to specified periods of time, i.e. 20 minute fire rated door. Various materials can produce higher or lower fire ratings. These doors are primarily used to meet specific building codes.
    • Storm Doors – Applied to the exterior of an entry door and often allows for ventilation though a screen.

    Glass & Energy Efficiency

    • Single Pane Glass – Single pane glass is just one piece of glass. This is the older style of windows. Most windows are now manufactured with a dual pane.
    • Dual Pane Glass – Two pieces of glass are sealed with a space between.
    • Clear Insulated glass – Double pane glass but without any type of upgrades for energy efficiency, i.e. dual pane.
    • Low E Glass – Dual pane glass with a metal oxide coating, usually iron, that is applied to the glass at the time of its manufacture to reflect infrared/heat away from the window. Increases the energy efficiency of the glass by reflecting heat away from the window. This glass also stops sun bleaching of blinds, carpets, furniture, etc. as it does not allow the infrared light to penetrate through the glass.
    • Solar Heat Gain Coefficient (SHGC) – The amount of heat transmitted directly and absorbed into the unit that transmits inwards. Based on a rating of 0-1. The lower the SHGC the better the insulating factor of the unit. This is a recognized rating system by the National Fenestration Rating Council.
    • U Factor – The rate of heat loss of the overall unit, including glass, frame, sashes, etc. The lower the U-Factor the more resistant the unit is to heat and has better insulating properties. This is a recognized rating system by the National Fenestration Rating Council.
    • Decorative Glass – Any type of decorative glass in windows or doors that is not just clear glass, i.e. stain glass, glass with caming, etc.
    • Seal Failure – A.K.A Moisture between the glass, when the seals around the glass of windows and/or doors fail and moisture infiltrates the interior of the two glass panes.

    Misc. Parts & Pieces

    • Astragal – Moulding profile used to cover the seal between two doors. Astragals often have a throw bolts that secure the passive door on the unit by latching it to the top and bottom of the door frame.
    • Brickmould – Exterior casing used on the outside of windows and doors. This exterior trim contrary to its name is not only used on brick but also used on siding, Hardie Plank ™, and any other exterior materials.
    • Drip Caps – A strip that is applied to the top of windows that is caulked in and diverts water away from the window and does not allow water to seep behind the window or into the wall.
    • Door Sweep – Weather stripping attached to the bottom of the door panel. Used to help keep out elements.
    • Extension Jambs – Extension jambs are interior wood strips used to finish the space between the inside of window frame and the interior wall, i.e. average casement window jamb depth is only 2 7/8”, a 2×4 is 4 9/16”, the extension jamb is used to fill the difference.
    • Fibrex™ — An Andersen window corporation trademarked product. Fibrex is made from a polymer resin similar to fiberglass, but uses reclaimed wood particles to produce a sustainable, durable and energy efficient product.
    • Grilles – Sometimes referred to as muttons or grids. They are the grids in a window and can be applied between the glass, permanently affixed to the glass on the exterior and the interior, or be removable.
    • Interior Casing/Moulding – The moulding that is used to trim out around the interior of windows and doors.
    • J-Channels – Used with vinyl windows, the sides and top of the window have a pocket so the siding can recess behind it and butt up against the window frame.
    • Jambs – The side and top portions of the window and door frame that make up the top and sides of the frame, i.e. side jambs or head jambs.
    • LVL Wood Technology – Laminated Veneer Lumber is an engineered wood product that utilizes multiple layers of wood strips that are held together using an adhesive. The advantages of typical wood is that is straighter, stronger and more uniform and tends to resist warping, bowing twisting or shrinking compared to traditional wood products. LVL is used in the production of some doors and windows.
    • Mullions/mull kits – Materials used to join multiple windows and doors together making for one single uniform unit.
    • Multipoint Lock System – Door locking system that utilizes multiple points in the door frame and/or adjoining panels for locking. Provides for a more secure locking system than a traditional single or double bore system.
    • Rail – The top and bottom of window sashes.
    • Sidelites – Fixed and venting units that flank the sides of entry door units.
    • Sills – The bottom portion of the window or door frame.
    • Single Bore/ Double Bore – Door panel is routed for single hardware, double bore is routed for hardware and deadbolt.
    • Stile – The left and right sides of window sashes.
    • Transoms – Window units affixed atop other window and door units, usually non-venting.
    • Window Capping – Placing a layer of material over the top of another material. Usually aluminum is used to cap wood. This process is used to protect exterior materials that are generally not weather resistant with materials that are designed to be weather resistant.
    • Weather stripping – Material used around window and doors to help stem the infiltration of wind, weather and temperature.