A home window, whether a new window or a replacement window, isn’t just a piece of glass—it’s a system of parts working together to provide comfort, efficiency, and style. When customers understand how it all fits, they make smarter buying decisions. For contractors, this easy guide will help walk your customers through the basic parts of a Marvin window. They’ll appreciate understanding what they’re buying—and you’ll stand out for being both knowledgeable and helpful.
Here are 17 essential window terms that can help guide more confident, informed window-buying decisions:
Frame & Sash
- Frame: The stationary structure that holds the window—made up of a head jamb (top), side jambs, and the bottom sill.
- Sash: The movable or fixed part of the window that holds the glass. Casement windows and double‑hung units, such as Marvin Ultimate Double Hung G2 Windows, have one or two operating sashes, while fixed sashes stay put.
Contractor tip: Highlight sash types to help homeowners consider ventilation and cleaning ease.
Rails & Stiles
- Rail: Horizontal pieces—top rail or bottom rail—forming the sash’s upper and lower edges.
- Stile: Vertical side pieces of the sash.
Buying tip: Slimmer rails and stiles mean more glass and better daylight—an easy value-add in your pitch for Marvin windows.
Mullions & Muntins (aka Grilles)
- Mullion: A structural vertical bar separating side‑by‑side panes or window units.
- Muntin (or grille): Decorative bars creating a multi‑pane look—usually between glass layers or clipped on.
Homeowner insight: Want that classic grid but easy cleaning? Grilles between glass (GBGs) are ideal.
Low‑E Glass & Argon Gas
- Low‑E (Low Emissivity) coatings reflect heat to improve insulation.
- Argon Gas: Fills the space between glass panes to slow heat transfer and increase energy efficiency, such as the Marvin Elevate Collection.
Let homeowners know: combining Low‑E and argon in Marvin windows means lower energy bills and more comfort—unique selling points you can stress.
Window Types at a Glance
Knowing window styles helps guide design discussions. Common Marvin models include:
- Double‑hung: Two sashes slide vertically—ideal for airflow.
- Casement/Awning: Wind-out or crank-out windows—excellent for hard-to-reach spaces.
- Fixed Binges & Picture Windows: Non-moving, energy-efficient, and optimized for daylight.
- Bay/Bow Windows: Multi‑unit combinations for expanded interiors and curb appeal.
Homeowner know-how tip: Reviewing these options enables homeowners to visualize their home’s rhythm and charm as reflected through Marvin windows.
Safety & Code Terms
- Sash Limiter: A device that restricts how far a window can open, commonly used on upper floors for child safety and code compliance.
- Egress Window: A window large enough and positioned properly to serve as an emergency exit, often required in bedrooms and basements.
- Tempered Glass: A heat-treated safety glass that breaks into small, blunt pieces, often required near doors, bathtubs, and at floor level.
- Window Opening Control Device (WOCD): A built-in mechanism that limits opening width but can be released for emergency egress.
- Design Pressure (DP) Rating: A structural rating that measures how much wind load a window can withstand, important in coastal and storm-prone regions.
Contractor local knowledge tip: Contractors familiar with local codes can ensure windows meet safety standards from the start, saving time and costly rework later.
See Marvin Windows in Person
Contractors, rely on Dunn Lumber to supply high-quality Marvin products—and use the in-store window displays to help homeowners visualize potential. Homeowners can visit our showroom to explore Marvin windows firsthand.
Help Customers Understand the System Behind the Glass
When homeowners understand that windows are more than panes of glass—that they’re systems designed for insulation, security, and style—they make smarter, more confident choices. Dunn Lumber helps you guide that process. With real Marvin window displays at select locations, your customers can see and compare options for themselves. Combine that hands-on experience with your trusted expertise, and you’re not just finishing a project—you’re building lasting satisfaction from the first consultation to the final install.
Ready to get started? Contact us to learn how our window experts can support your next project—whether you’re building new, replacing old, or guiding a customer through the options.
