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Window Installation Glossary

Understanding window installation terminology helps you communicate confidently with contractors, evaluate quotes, and make smarter decisions for your home. This glossary covers the essential terms you need to know before, during, and after a window installation project.

Your Quick Reference Guide

Essential Window Installation Terms Every Homeowner Should Know

Rough Opening

The rough opening is the framed hole in a wall where a window unit will be installed. It is typically slightly larger than the window itself to allow for adjustments, shimming, and insulation. A properly sized rough opening is critical for a level, secure, and weathertight window installation.

Flashing

Flashing refers to thin strips of weather-resistant material, usually metal or self-adhesive membrane, installed around the window frame to prevent water infiltration. It directs moisture away from the wall assembly and is one of the most important components of a waterproof window installation. Improper flashing is a leading cause of water damage around windows.

Jamb

The jamb is the vertical side framing of a window unit that forms the inner lining of the window opening. Jambs support the sash and provide structure for the entire window assembly. Extension jambs may be added when a wall is thicker than the standard window depth to ensure a clean, finished look.

Sash

The sash is the movable or fixed frame that holds the window glass in place. In double-hung windows, both the upper and lower sashes can slide up and down independently. The condition and fit of the sash directly affect energy efficiency, ease of operation, and the overall weathertightness of the window.

Weatherstripping

Weatherstripping is a sealing material applied around the edges of a window sash to prevent drafts, moisture, and outside air from entering the home. It plays a key role in energy efficiency and indoor comfort. Over time, weatherstripping can wear out and may need to be replaced to maintain a proper seal.

Low-E Glass

Low-E, or low-emissivity, glass is a type of energy-efficient glazing coated with a thin metallic layer that reflects heat while allowing visible light to pass through. It helps keep homes warmer in winter and cooler in summer by reducing heat transfer through the glass. Low-E glass is a common upgrade option during window installation projects.

Casing

Window casing is the decorative trim molding applied around the interior and exterior edges of a window frame to cover the gap between the window unit and the wall surface. It gives the installation a finished, polished appearance and also helps seal the window against air and moisture infiltration. Casing styles vary widely to match different architectural aesthetics.

U-Factor

The U-factor is a measurement of how well a window insulates against heat loss, expressed as a number typically ranging from 0.20 to 1.20. The lower the U-factor, the better the window performs at retaining heat inside the home. Understanding U-factor ratings helps homeowners compare window products and choose the most energy-efficient option for their climate.

Why Homeowners Trust Us

Why Choose Michael C Graham & Son Construction

We provide top-quality window and roofing materials designed for durability and long-term performance in Central New York's demanding climate, ensuring your installation stands the test of time.

Our team delivers detailed and transparent estimates so you fully understand project costs, material choices, and expected outcomes before any work begins — no surprises, no guesswork.

We make home improvement accessible with competitive pricing and solutions tailored to fit your budget, helping you get the quality installation you need without unnecessary financial stress.

We treat every customer like family, guiding you through each step of the installation process with clear communication, professional care, and a commitment to your complete satisfaction.

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Make Confident Window Decisions

Now that you know the key terms, you're better prepared to plan your window installation project. Reach out to our team to get a transparent estimate and expert guidance tailored to your home.