Guide to Types of Windows & Skylights

Definitions of different types of windows & skylights
- Table outlining properties of each type of window; illustrations & definitions of single hung window, double hung window, casement window, slider windows, awning window, hopper window, tilt and turn windows, Text describing the operation & features of each type of window

Questions & Answers about the properties of and names of different types of windows
References

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This article describes the types of windows used in residential buildings, their features, how they work, and the advantages or disadvantages of each window type, including single hung windows, double hung windows, sliders, casement windows, awning type windows, hopper windows, and tilt-turn windows.

Best Practices Guide to Selecting, Inspecting, Diagnosing, Repairing Skylights, Windows & Doors

In this article series we discuss the selection and installation of windows and doors, following best construction and design practices for building lighting and ventilation, with attention to the impact on building heating and cooling costs, indoor air quality, and comfort of occupants. We review the proper installation details for windows and doors, and we compare the durability of different window and door materials and types. This article includes excerpts or adaptations from Best Practices Guide to Residential Construction, by Steven Bliss, courtesy of Wiley & Sons.

See WINDOWS & DOORS our home page for window and door information, and also see WINDOW TYPES - Photo Guide for a photographic guide to window and door types and architectural styles.

Window Types, Guide

As discussed in Best Practices Guide to Residential Construction Chapter 3, BEST PRACTICES GUIDE: WINDOWS & DOORS:

Windows have a bigger impact on the quality of life in a home than almost any other building component. They affect heating and cooling costs, natural lighting levels, ventilation quality, and the comfort of occupants year-round.

Subjected to high ultraviolet (UV) exposure, extremes of weather, and hundreds of operations over their service lives, windows must be well-engineered from durable materials if they are to provide satisfactory service.

It is well worth investing the time and money to select the right windows for the job and to install them properly.

The most common types of operable windows are double-hung, casement, and sliding.

Awning-style windows are commonly used either near grade to let light into basements or high on a wall for privacy. Tilt-turn windows, European imports that swing inward like a door on hinges, are often used in large sizes as emergency exits.

Windows with compression-type seals are the tightest, and windows that swing open provide the best ventilation (see Figure 3-1 above-left).

Common window types and their characteristics are summarized in Table 3-1 below. [Click any table or illustration for an enlarged, detailed version.]

Single- and Double-Hung Windows

The most common windows in the United States, doublehungs have upper and lower sash offset so both can slide up and down. Only the lower sash moves in the less common single-hung window. In older homes, the operable sash were connected by rope to heavy iron counterweights to hold the upper sash in place and to assist with raising the lower sash.

Modern double-hung windows ride up and down in metal or plastic tracks called jamb liners and use hidden springs in place of sash weights.

On many of the newer models, the sash are designed to tilt in for easy cleaning.

At left the sketch, courtesy of Carson Dunlop Associates illustrates the difference between a single-hung window sash and a double-hung window. As you can see, only the lower sash is movable in a single-hung window sash.

Because the top sash overhangs the bottom, and both are recessed in the frame, double-hung windows shed rain well and can be left open at the bottom in a light rain. They use exterior screens that are out of the way and inconspicuous. However, ventilation is limited to half the area of the frame, and visibility is somewhat hampered by the meeting rails, which often sit near eye level.

Also, because they rely on slide-by rather than compression-type weather-seals, many double-hungs have air leakage rates nearly twice that of casements. With improvements in materials and designs in high quality units, however, the performance gap has narrowed, at least when the windows are tested (with brand-new weather seals).

Although probably not the tightest windows in a high wind location, in general, double-hungs offer a versatile, moderately priced, and trouble-free option.

Sliding Windows or Gliding Windows: design features

Sliders can offer large horizontal expanses of glass and operable sash that do not interfere with interior or exterior space. They are more common in western states, while double-hungs and casements prevail on the East Coast.

Our photo (left) shows Andeson gliding windows (photo-right) and casement windows (photo-left) that we [DJF] recently installed during a log cabin renovation in Two Harbors, MN.

Designing a window that slides sideways presents a few challenges.

First, the lower track must rely on weep holes to drain away water, and second, any grit that collects in the lower track tends to impair the sliding action.

If the weeps clog up, water may find its way into the sill or framing over time. Also, pushing a stuck window sideways is an awkward motion that tends to strain the back. (Also see STORM WINDOW WEEP HOLES).

As with double-hung windows, ventilation is limited to rougly 50% of the framed opening, and slide-by weather-seals are less effective than compression seals. And if the slider is large enough it can also qualify as an egress window.

List of Glider / Slider Window Defects

To avoid problems with slider windows, look for high-quality windows that slide freely. Also, consider alternatives such as a picture window with a casement along one side for ventilation.

For a list of common installation or maintenance defects that cause problems at gliding or sliding windows, see SLIDING GLIDING WINDOW DEFECTS This article describes windows with lost seal, clogged slider track drainage openings, out of square installation and other window defects that should be easy to spot during a visual inspection.

Casement Windows - Natural Building Ventilators

Casement windows provide a more contemporary look than traditional double-hungs and can provide large uninterrupted views. If oriented to open into the prevailing winds, the sash acts like a big wind scoop, directing breezes into the house. And when closed, the compression seals create a tight fit that only gets tighter with oncoming winds.

Casement windows are not without problems, however. The outward swinging sash is vulnerable to water damage if the top is not fully clad, and the sash can clash with screen doors or encroach on deck spaces.

Or worse. Our casement window photo at left (DF) shows spectacularly poor planning: these windows cannot open more than a few inches without jamming against the soffit overhang!

Also, hardware problems such as stripped crank handles or broken linkages are not uncommon, particularly on lower-end units or large units with heavy sash. An occasional squirt of lubricant on the crank mechanism and hinges can go a long way toward preventing problems.

Large, heavy sash can also rack slightly out of square over time, requiring a push from the outside to fully close. Sometimes this can be fixed by tweaking the hardware, but a new sash may be required.

For best results with casement windows, choose units with sturdy sash construction, heavy-duty hardware, and sash that are protected on top from the elements.

Awning Windows and Hopper Windows: design features

Awning windows swing outward from top hinges, and hopper windows swing inward from bottom hinges. Awning windows s are useful for privacy windows and other high-up locations like clerestories, while hoppers are often used in basements.

A principal advantage of awning windows is that they can be left open for ventilation with less risk of water entry should a rain shower occur. Our photo (left) shows a modern awning-style window in a newly-renovated building in Buenos Aires, Argentina (-DF).

Both awnings and hoppers can be combined with fixed glazing to add ventilation below a picture window.

Because they rely on cranking mechanisms, these windows have some of the same problems as casements.

But without the heavy vertical sash, they are less prone to malfunction.

For hard-to-reach locations, a pole, pull-chain, or motorized operators can be used to open and close awning or hopper style windows.

Tilt-Turn Windows

Developed in Europe, tilt turn windows rely on intricate hardware controlled by a single lever that allows the windows to either swing in like a door or tilt in at the top like a hopper.

In tilt mode, the sash are open only a few inches, allowing the windows to provide ventilation in a locked house (see Figure 3-2 at left).

When closed, the lever locks the window tightly in four to six locations, providing the tightest fitting windows available as well as excellent security against would-be thieves. And with their easy-to-operate in-swinging mode, large-sized tilt-turn windows often do double duty as emergency exits.

While tilt-turn windows offer several useful features, they are not commonly seen in the United States, perhaps because of the in-swinging sash and relatively high cost. Also, they do not typically come with screens, making them problematic in areas with summer pests. While not heavily marketed in the United States, they can be found here in wood, aluminum, aluminum-clad, and solid vinyl frames, the least expensive option.

Also see WINDOW TYPES - Photo Guide.

Door Manufacturers & Products Guide

Benchmark Entry Systems (division of Therma-Tru Doors) www.benchmarkdoors.com Steel and fiberglass entry doors

Jeld-Wen Windows and Doors www.jeld-wen.com Wood, wood composite wood, fiberglass, and steel entry doors

Kolbe Windows and Doors www.kolbe-kolbe.com Wood, steel, and fiberglass entry doors with LVL core and optional extruded-aluminum cladding on frame

Lamson-Taylor Custom Doors and Millwork www.lamsontaylor.com Custom pine and hardwood entry doors with foam insulation core

Masonite Corp. www.masonite.com Steel, wood-edged steel, and fiberglass entry doors

Peachtree Doors and Windows www.peach99.com Steel and smooth and textured fiberglass entry doors

Pella Windows and Doors www.pella.com Fiberglass and steel entry doors

Phoenix Door Manufacturing Company www.phoenixdoor.com Softwood and hardwood entry doors up to 8 ft. high and custom designs

Simpson Door Company www.simpsondoor.com Douglas-fir, hemlock, oak, and mahogany entrance doors, including custom doors; also primed MDF, particleboard, and composite wood doors

Stanley Door Systems (division of Masonite) www.stanleyworks.com Steel and fiberglass entry doors

Weathershield Windows and Doors www.weathershield.com Wood and steel entry doors, with wood, vinyl, aluminumclad, and vinyl-clad frames

Taylor Building Products www.taylordoor.com Steel (stainable finish) and fiberglass entry doors

Therma-Tru Doors www.thermatru.com Steel and fiberglass entry doors with optional vinyl-clad jambs

Skylight Manufacturers & Product Sources

Andersen Windows and Doors www.andersenwindows.com Skylights and roof windows with exterior sash clad with glass-fiber-reinforced material

Milgard Windows and Doors www.milgard.com Skylights with aluminum frames (thermal break optional) with vinyl subframes on operable models; optional motorized controls with rain sensor

Pella Windows and Doors www.pella.com Wood interior, aluminum exterior, optional motorized controls, and manual or motorized fabric-pleated shades

Roto Frank of America www.roofwindows.com Wood interior, aluminum exterior, optional motorized controls, and manual or motorized fabric-pleated shades; Sweet16 model fits 16 in. o.c. framing

Velux America Inc. www.velux.com Skylights and roof windows with wood interior and aluminum-clad exterior. Options include insect screens, blinds, motorized controls and shades with rain sensor, electrochromatic glass, and flashing kits for metal and tile roofs and mulled units

Skylight Light Tube Manufacturers & Sources

SolaTube www.solatube.com Light tubes from 10 to 21 in. in diameter; options include electrical lighting, daylight dimmer, and integral bath fan

Sun-Tek Skylights www.sun-tek.com Light tubes from 10 to 21 in. in diameter; options include electrical lighting and multitube Spyder skylight

Velux America Inc. www.velux.com Sun Tunnel light tubes from 14 to 22 in. in diameter with flexible or rigid tubes

Industry Associations for Windows & Doors

American Architectural Manufacturers Association (AAMA) www.aamanet.org

Efficient Windows Collaborative www.efficientwindows.org

National Fenestration Rating Council (NFRC) www.nfrc.org Sustainable by Design www.susdesign.com

Shareware calculators for sun angles, solar heat gain, and shading

Window and Door Manufacturers Association (WDMA) www.wdma.com

-- Adapted and paraphrased, edited, and supplemented, with permission from Best Practices Guide to Residential Construction.

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Technical Reviewers & References

Related Topics, found near the top of this page suggest articles closely related to this one.

Basic Housing Inspection, US DHEW, S 352.75 U48, p.144, out of print, but is available in most state libraries; New York State version, ca 1955, source of our window parts and window repair sketches.
Best Practices Guide to Residential Construction, by Steven Bliss. John Wiley & Sons, 2006. ISBN-10: 0471648361, ISBN-13: 978-0471648369, Hardcover: 320 pages, available from Amazon.com and also Wiley.com. See our book review of this publication.
Carson, Dunlop & Associates Ltd., 120 Carlton Street Suite 407, Toronto ON M5A 4K2. (416) 964-9415 1-800-268-7070 info@carsondunlop.com. The firm provides professional home inspection services & home inspection education & publications. Alan Carson is a past president of ASHI, the American Society of Home Inspectors. Thanks to Alan Carson and Bob Dunlop, for permission for InspectAPedia to use text excerpts from The Home Reference Book & illustrations from The Illustrated Home. Carson Dunlop Associates' provides:
- Commercial Building Inspection Courses - protocol ASTM Standard E 2018-08 for Property Condition Assessments
- Home Inspection Education Courses including home study & live classes at eleven colleges & universities.
- Home Inspection Education Home Study Courses - ASHI@Home Training 10-course program.
  Special Offer: Carson Dunlop Associates offers InspectAPedia readers in the U.S.A. a 5% discount on these courses: Enter INSPECTAHITP in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
- The Home Reference Book, a reference & inspection report product for building owners & inspectors.
  Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.
- The Home Reference eBook, an electronic version for PCs, the iPad, iPhone, & Android smart phones.
  Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter inspectaehrb in the order payment page "Promo/Redemption" space.
- The Illustrated Home illustrates construction details and building components, a reference for owners & inspectors.
  Special Offer: For a 5% discount on any number of copies of the Illustrated Home purchased as a single order Enter INSPECTAILL in the order payment page "Promo/Redemption" space.
- The Horizon Software System manages business operations,scheduling, & inspection report writing using Carson Dunlop's knowledge base & color images. The Horizon system runs on always-available cloud-based software for office computers, laptops, tablets, iPad, Android, & other smartphones.

Books & Articles on Building & Environmental Inspection, Testing, Diagnosis, & Repair

Our recommended books about building & mechanical systems design, inspection, problem diagnosis, and repair, and about indoor environment and IAQ testing, diagnosis, and cleanup are at the InspectAPedia Bookstore. Also see our Book Reviews - InspectAPedia.

The Home Reference Book - the Encyclopedia of Homes, Carson Dunlop & Associates, Toronto, Ontario, 25th Ed., 2012, is a bound volume of more than 450 illustrated pages that assist home inspectors and home owners in the inspection and detection of problems on buildings. The text is intended as a reference guide to help building owners operate and maintain their home effectively. Field inspection worksheets are included at the back of the volume. Special Offer: For a 10% discount on any number of copies of the Home Reference Book purchased as a single order. Enter INSPECTAHRB in the order payment page "Promo/Redemption" space. InspectAPedia.com editor Daniel Friedman is a contributing author.

Or choose the The Home Reference eBook for PCs, Macs, Kindle, iPad, iPhone, or Android Smart Phones. Special Offer: For a 5% discount on any number of copies of the Home Reference eBook purchased as a single order. Enter INSPECTAEHRB in the order payment page "Promo/Redemption" space.

Building inspection education & report writing systems from Carson, Dunlop & Associates Ltd

Decks and Porches, the JLC Guide to, Best Practices for Outdoor Spaces, Steve Bliss (Editor), The Journal of Light Construction, Williston VT, 2010 ISBN 10: 1-928580-42-4, ISBN 13: 978-1-928580-42-3, available from Amazon.com
The Journal of Light Construction has generously given reprint permission to InspectAPedia.com for adaptations, quotations, or reproductions used at this website. All rights and contents of the JLC material are ©Journal of Light Construction and may not be reproduced in any form.
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