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Architectural Glass & Glazing
The glass you choose determines most of the thermal, acoustic, safety, and visual performance of your window or door. Here's what you need to know.
Why Glazing Matters
The Glass Makes the Window
In a modern window or door, the glazing unit accounts for the majority of the opening's surface area — and the majority of its thermal, acoustic, and safety performance. Selecting the right glass type and unit configuration for each position in a building is one of the most consequential specification decisions in any window and door project.
The profile system determines the structural form of the opening. The glass determines what happens thermally, acoustically, and visually across that opening. Getting both right — and making sure the glass specification is compatible with the system's glazing capacity — is part of what we help our clients do.
The guide below provides an overview of the principal glass types available for architectural applications. These descriptions are educational and general. Final glazing selection for any project depends on the system being used, the opening dimensions, structural loads, applicable safety codes, building performance objectives, and budget.
Glass Types
Architectural Glazing Options
Insulated Glass Units (IGU)
Insulated glass units — commonly called double glazing or triple glazing — consist of two or three glass panes separated by a hermetically sealed air or gas-filled cavity. The cavity acts as a thermal barrier, significantly reducing heat transfer compared to single glazing.
Double-glazed units (two panes) are the residential standard. Triple-glazed units (three panes) provide additional thermal resistance and can meaningfully improve acoustic performance, at the cost of additional weight and unit thickness.
Key consideration: The spacer bar material, cavity gas (air, argon, or krypton), and glass pane specifications all affect the unit's final thermal performance (Ug value).
Low-Emissivity (Low-E) Glass
Low-E glass has a microscopically thin metallic coating applied to one surface. This coating reflects radiant heat back into the space from which it came — in winter, reflecting interior warmth back inward; in summer configurations, reflecting solar infrared back outward.
Low-E coatings are a standard feature of high-performance IGUs and are nearly always specified in climate-sensitive applications. Different coating positions and formulations affect the balance between thermal insulation (g-value) and visible light transmission.
Key consideration: "Passive" Low-E coatings maximize solar heat gain for winter heating benefit; "solar control" Low-E coatings limit solar gain for cooling climates. The right choice depends on climate, orientation, and building type.
Tempered Safety Glass
Tempered (toughened) glass is produced by heating float glass to near its softening point and then rapidly quenching the surfaces. This creates a compressive stress layer on the surfaces and a tensile core, resulting in glass that is approximately four to five times stronger in bending than annealed glass of the same thickness.
When tempered glass does break, it fractures into small, relatively blunt fragments — rather than the large, sharp shards of annealed glass — significantly reducing injury risk.
Key consideration: Required in many positions by building codes — especially in doors, sidelights, low-level glazing, wet areas, and anywhere the risk of human impact is elevated. Cannot be cut after tempering.
Laminated Safety Glass
Laminated glass consists of two or more glass panes bonded together with one or more interlayers — typically polyvinyl butyral (PVB) or a cast resin. When broken, the interlayer holds the glass fragments in place, preventing them from falling or scattering.
Laminated glass is used for applications requiring resistance to penetration, structural integrity after breakage, fall protection, and enhanced acoustic performance. It is the standard for windscreens and is required in overhead glazing and many safety-critical positions in buildings.
Key consideration: Acoustic performance improves with thicker or asymmetric interlayer specifications. Overhead glazing typically requires laminated glass by code regardless of height.
Acoustic Glazing
Acoustic glazing uses specialized glass combinations — typically laminated glass with acoustic-grade interlayers, asymmetric pane thicknesses, or wider cavities — to improve airborne sound insulation performance beyond what standard double glazing achieves.
The primary mechanism is disrupting the resonant frequencies at which standard glass units transmit sound. Acoustic-grade PVB interlayers are significantly more effective at sound damping than standard PVB. Asymmetric pane thicknesses (e.g., 4mm + 6mm rather than 4mm + 4mm) spread the resonance across a broader frequency range.
Key consideration: Acoustic performance is specified as Rw (weighted sound reduction index) in dB. The frame sealing performance is equally important — a well-sealed frame with standard glass will outperform a poorly sealed frame with acoustic glass.
Solar-Control Glass
Solar-control glass uses coatings or body tints to reduce the amount of solar energy (particularly infrared and ultraviolet radiation) that passes through the glazing into the building. This limits overheating in cooling-dominated climates and reduces the load on mechanical cooling systems.
Solar-control glass is characterized by its g-value (solar heat gain coefficient) — lower values mean less solar energy transmission. The challenge is balancing solar control against visible light transmission (VT): many solar-control coatings also reduce the amount of daylight entering the space.
Key consideration: Critical for south- and west-facing large glazed areas in the NJ/mid-Atlantic climate. Must be balanced against daylighting objectives.
Tinted & Reflective Glass
Tinted glass incorporates coloring agents into the glass body during manufacture, producing glass in grey, bronze, blue, or green tones. The tint reduces solar heat gain and visible light transmission, and gives the façade a distinct appearance.
Reflective glass has a metallic coating applied to one surface, creating a mirror-like exterior appearance that significantly reduces solar heat gain. It is commonly used in commercial facades where privacy, solar control, and aesthetic consistency are priorities.
Key consideration: Tinted and reflective glass reduce solar transmission at the cost of visible light. Interior lighting at night may produce a reverse-mirror effect on reflective glass. Requires careful specification in residential contexts.
Privacy Glass
Privacy glazing includes several distinct technologies: patterned/obscure glass uses surface texturing to obscure vision while transmitting diffused light; frosted glass achieves a similar result through acid-etching or sandblasting; switchable (smart) glass changes from transparent to opaque on demand via applied voltage.
Privacy glass is used in bathroom and wet-area windows, office partitions, conference rooms, and any position where visual separation is needed without sacrificing light transmission.
Key consideration: Obscure glass patterns vary in the degree of visual obscuration — some allow silhouette recognition at close range. For full privacy, higher-obscuration patterns or frosted glass are appropriate. Switchable glass adds significant cost.
Security-Enhanced Glazing
Security-enhanced glazing uses laminated glass constructions with thicker, tougher interlayers to resist forced entry, attack, and blast. This ranges from general attack-resistance laminates (classified to EN 356) through to bullet-resistant and explosion-resistant specifications.
For residential and commercial projects where RC2 security class is being specified, the glazing must meet the requirements of the EN 1627 classification — the glass unit and the frame hardware work together to achieve the resistance class, and the glazing specification must be confirmed as part of the full window or door specification.
Key consideration: Security glazing is significantly heavier than standard glass. Weight must be accounted for in system selection and hardware specification. Not interchangeable with standard glazing in the same frame without respecification.
Glazing Selection Must Be Confirmed Per Project
Final glazing depends on the profile system being used, the opening dimensions, the unit thickness the system's glazing rebate can accommodate, structural requirements, applicable safety codes, and the project's thermal, acoustic, and visual performance objectives.
The glass types described above are general categories. Within each category, specific products from glazing manufacturers vary considerably in their performance values. Glass selection must be confirmed as part of the project documentation process, coordinated with the frame system specification.
If you have specific thermal, acoustic, or safety performance targets, share them with us and we will help you identify an appropriate glazing specification compatible with the system and opening dimensions.
Ready to Specify
Discuss Your Glazing Requirements
Whether you have specific performance targets, safety code requirements, or are simply unsure which glass types suit your project, our team can help you work through the options.