How-To

Top 7 Questions to ask when Buying Windows

There are lots of questions when it comes to windows. Here are answers to the most frequently asked questions.

Windows are both simple and extremely complex. Their basic function has not changed since the pioneer days when greased paper was used to cover holes in the walls and allow light indoors. Thankfully, modern technology has led to great improvement in window design and function, which has resulted in an array of window options, as well as some new questions. Learning answers to those questions will ease the work of maintaining windows or the process of shopping for new ones.

Is there a difference between replacement windows and windows for new construction?

Yes. Windows for new construction are designed to be installed during the construction process, usually prior to siding installation. Most have flanges that are fastened to the window framing. Replacement windows are sized to be fastened into an existing window opening without needing to remove any siding.

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What terminology do I need to know to talk about windows?

The study of fenestration (a fancy word for designing and arranging windows) involves a number of key terms that most homeowners may not know. Any primer on window terminology starts with identifying the parts of a window. Window performance and types also involve some new words and acronyms.

All windows, regardless of type, consist of glass panes, called glazing, that are secured within a four-part frame. The independent, framed glazing is called a sash. The vertical members of the sash are called stiles, and the horizontal pieces are the top rail and bottom rail. The sashes are installed within a framed opening trimmed by two side jambs, a head jamb, and a sill. How the sashes are installed and are opened and closed depends on the type of window.

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What types of windows do I have to choose from?

You’ll find a dozen or more general types of windows offered by manufacturers, but most windows installed in homes fall into six basic categories:

Double Hung Windows Consisting of two sash that slide up and down in tracks, double hung windows are very familiar and very popular. They offer excellent ventilation that can be adjusted according to which sash is opened. Airflow, however, is limited to half of the window opening area. Single-hung windows have a fixed top sash and an operable bottom sash.

Casement Windows Sometimes called crank-out windows, casements are single-frame windows hinged on one side, so they open outward, usually by means of a hand crank mounted in the frame sill. They offer full ventilation when open and seal very tightly closed.

Awning Windows Hinged on top, awning windows swing outward, usually by means of a crank. Mostly horizontal in configuration, they are often installed high on the wall and are popular in basements. Hopper windows are similar, but open inward.

Bay and Bow Windows These multi-window units project out from the wall, increasing light introduction and providing a horizontal surface for plants or even a window seat. Bay windows are more angular, with one large picture window in the center and a tall, narrow side window at each end. Bow windows usually include at least four similar-sized windows that create a more curvilinear projection than the angular bays. Traditional bay and bow windows include an attached roof structure for exterior shelter. The Marvin Skycove is a new and innovative take on this, replacing the roof with overhead glass for an immersive experience that can expand usable living space by up to 20 feet. Certified and warrantied, the Skycove is much easier to install than another custom-built option.

Picture Windows A non-operable window, generally large in size and installed in a prominent spot. Usually square or rectangular, but available shapes include round-top, octagon, and other specialty shapes.

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What are my options when it comes to window glass?

A quality window unit has two or three panes of glass in the frame, separated by thin spaces that are filled with inert gas (usually argon) and sealed. These insulating glass units greatly decrease the amount of heat loss through the window, as well as limiting condensation or frosting. In most cases, triple panes (tri-pane) windows have somewhat better insulation performance than dual-pane units. Quality window glass is also treated with a low-emissivity (Low E) coating of microscopically thin metal such as silver. The Low E coating blocks UV radiation and radiant heat transfer.

In regions prone to hurricanes, codes require that windows be fitted with impact glass that resists breakage and does not shatter like standard glass if it does break. A hybrid of tempered glass and laminated glass, impact glass is also required in areas where someone could fall into the glass, such as floor-level windows and windows in stairways.

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Top 7 questions to ask when buying windows

How are windows rated for energy efficiency?

Every window or glass door has numeric energy efficiency ratings assigned to it by oversight agencies.

The best-known of these is the ENERGY STAR program run by the US EPA and the Department of Energy and verified by the National Fenestration Rating Council (NFRC). Windows are tested and rated according to two measures: The U-Factor and the Solar Heat Gain Coefficient (SHGC). The U-Factor tells you how well the window keeps heat indoors. The ratings range from 0.20 to 1.20. The lower the number the better, especially in Northern Climates.

The SHGC describes how well the window keeps heat out. It ranges from 0 to 1, with lower numbers indicating higher efficiency. It is more important in Southern climates. So regionality plus the U-Factor and SHGC determine if a window earns an ENERGY STAR sticker.

The NFRC rating label is perhaps a more instructive guide for choosing a window because it reveals the U-Factor and NFRC metrics, along with a couple of others, which allows you to make one-to-one comparisons of the energy efficiency of windows you are considering.

How to clean windows

What is the best way to clean windows?

There is more than one effective way to clean your windows. One inexpensive method is to start by making your own cleaning solution by adding warm water and a teaspoon of dishwashing soap to a 5-gallon bucket. Scrub the window with a scrubber or clean sponge that is damp with washing solution. Then, starting at the top, wipe off the solution with a lint-free cloth or a squeegee. If using a cloth, try to have only dry areas contacting the window at each pass. For the best results, wash the windows when they are not getting direct sunlight.

How to clean windows

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What material should I choose for my windows?

When considering materials for the window frames, jambs, and trim, there are four main categories of materials from which to choose. In some cases, you can choose to have two materials—wood for the interior and aluminum clad exterior, for example. Each material has unique characteristics, from design elements to performance features. To select the right material for you, consider factors like the climate you live in, the style of your home, and aesthetic preferences.

Wood Wood and windows are a great match. The species used in window construction and cladding have superior structural integrity, yet just enough flex to allow for some movement—but not too much—as humidity and temperature fluctuate. Wood is also easy to shape into profiles you cannot achieve with other materials. And it accepts a variety of painted or stained finishes very effectively.

When it comes to wood species, the most common is pine. It may be used on window interiors and exteriors, although it is sometimes covered, or clad, on the exterior with extruded aluminum or fiberglass cladding that makes the outside virtually maintenance-free. Wood is also an efficient insulator. Douglas Fir may be substituted for normal pine to provide a strong vertical wood grain and slightly better strength.

Oak is selected as a window material mostly for aesthetic reasons. Today, White Oak is the most common variety. Because it is harder to machine and join, and less common, oak costs more than pine. But the visual effects can be stunning. Meanwhile, mahogany, generally referred to as Honduran Mahogany, is a beautiful, exotic hardwood with deep, rich tones. It is also scarce and becoming scarcer (read: more expensive) due to overharvesting. Be sure any Mahogany window you purchase is made with wood featuring Forest Stewardship Council certification for responsible growth and harvesting.

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Learn more about fiberglass windows

Fiberglass

Fiberglass is a manmade material, so you will find a wide variety of quality and performance standards. Marvin offers two types of fiberglass that both provide great insulation and have the advantage of dimensional stability that is very similar to window glass, so the glass and the fiberglass frame expand and shrink at similar rates. This makes for premium durability. Avoid fiberglass with high concentrations of plastics and vinyls, or with sawdust and wood fillers. Premium fiberglass used in window construction is made simply with fiberglass fibers and resins that have high strength and do not sag or become brittle in extreme heat or cold. Some windows combine the weather-resistance of fiberglass or fiberglass cladding on the exterior with wood interiors that respond better to stain or paint.

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Aluminum

Aluminum is commonly used on the exterior of a window, generally to clad a wood window. It is very resistant to impact and extreme weather and thus is used extensively in areas prone to high winds and tropical storms. Marvin Coastline windows and doors, for example, are completely made of extruded aluminum for strength to withstand hurricane winds. Aluminum is low-maintenance and resistant to color fading and degradation. Look for aluminum cladding that is extruded into finished profiles in the manufacturing process. Extruded aluminum is thicker than roll-form aluminum and performs better.

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Vinyl

Vinyl Windows made from vinyl (usually PVC) are less costly, low-maintenance, and if the frames are not hollow, they are decent insulators. Because dark exteriors can soften or sag from heat or direct sunlight, most vinyl windows are white or buff, so the color selection is limited. They can also become brittle in very cold temperatures.

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