Glossary
Every term, explained.
The words you will see on approvals, spec sheets and estimates, in plain language, with why each one matters for your home.
- AAMA 2604
A mid-level industry standard for painted aluminum, tested for 5 years of South Florida exposure. It is the standard powder coat on many impact windows.
Why it matters: It performs well inland. Near the coast, a 2605 finish lasts longer.
- AAMA 2605
The highest industry standard for painted aluminum, tested for 10 years of South Florida sun exposure.
Why it matters: It is the best choice for strong sun and coastal homes, and some warranties require it near salt water.
- Anodized finish
A finish that hardens and colors the surface of the aluminum itself instead of painting it.
Why it matters: It shows the metal’s natural look. Its warranty is often shorter than that of paint finishes.
- Argon gas
A safe, invisible gas sealed between the panes of insulated glass.
Why it matters: It slows heat transfer better than air, improving insulation.
- Design pressure (psf)
The wind load a window or door is approved to resist, in pounds per square foot (psf). A rating like +80/−140 psf gives the inward push (+) and the outward suction (−).
Why it matters: Each opening on your home has a required pressure based on wind speed, height and location. The product must meet or exceed it, so a higher rating covers more openings.
- Egress
A window opening large enough for a person to escape through in an emergency.
Why it matters: Building codes require an egress window in bedrooms, so the style and size you choose matter there.
- Florida Product Approval (FL number)
A statewide product approval from the Florida Building Commission, shown as a number like FL42522. Its installation drawings set the approved sizes, glass and anchors.
Why it matters: Every window and door installed under a Florida permit needs an approval, either a Florida approval or a Miami-Dade NOA.
- Frame depth
How thick the frame is from inside to outside, in inches.
Why it matters: Deeper frames are usually stronger and reach larger sizes or higher ratings. They must also fit your wall opening.
- Heat-strengthened (HS) glass
Glass heated and cooled under control to be about twice as strong as ordinary glass. It breaks into larger pieces than tempered glass.
Why it matters: Approval drawings often call for HS glass inside laminated units to reach their pressure ratings.
- High-Velocity Hurricane Zone (HVHZ)
Miami-Dade and Broward counties, where the Florida Building Code applies its strictest testing and approval rules.
Why it matters: A product used in the HVHZ must be approved for it. Some products are approved only for outside the HVHZ, so they cannot be used in Broward or Miami-Dade.
- Insulated laminated glass
A laminated glass layer paired with a second pane, separated by a sealed space often filled with argon gas.
Why it matters: It keeps heat out and the air conditioning in far better than laminated glass alone, and it is quieter. It costs more and makes the unit heavier.
- Kynar (PVDF) finish
A high-performance fluoropolymer paint based on Kynar 500 PVDF resin. It is the classic finish that meets AAMA 2605.
Why it matters: It resists fading, chalking and salt air best, which is why manufacturers recommend it near the coast.
- Laminated glass
Two layers of glass bonded to a plastic interlayer. If the glass breaks, the pieces stay attached to the interlayer and the opening stays closed.
Why it matters: Laminated glass is what makes an impact window impact-resistant. It also blocks most UV and reduces outside noise.
- Large missile impact (LMI)
A test in which a 9 lb piece of 2x4 lumber is fired at the glass and frame, followed by thousands of wind-pressure cycles. The unit must stay closed and in one piece.
Why it matters: The Florida Building Code requires large-missile protection for openings up to 30 ft above ground in the windborne-debris areas that include South Florida.
- Low-E coating
A microscopically thin metal coating on the glass that reflects heat while letting light through.
Why it matters: In South Florida it cuts the sun’s heat coming in, lowering cooling costs and protecting floors and furniture from fading.
- Mullion
A structural bar that joins two or more windows or doors into one larger opening.
Why it matters: Mullions carry wind load too, so they need their own approval and anchoring.
- NFRC
The National Fenestration Rating Council, an independent organization that certifies window energy ratings such as U-factor and SHGC.
Why it matters: NFRC-certified numbers are tested the same way for every brand, so they can be compared fairly.
- Notice of Acceptance (NOA)
A product approval issued by Miami-Dade County after independent testing. It lists the approved sizes, glass, pressures and installation details, and it has an expiration date.
Why it matters: Your permit needs a current approval for the exact product. An NOA is the standard proof in the HVHZ.
- PVB interlayer
Polyvinyl butyral, the standard flexible plastic layer inside laminated glass.
Why it matters: PVB meets most residential needs at a lower cost. Higher pressures or larger sizes may call for SentryGlas.
- SentryGlas (SGP)
A stiff, strong ionoplast interlayer made by Kuraray, used in place of PVB in laminated glass.
Why it matters: It is much stiffer than PVB, so it often allows higher pressure ratings and larger sizes, and it stays clear at exposed edges. It usually costs more.
- Sidelite
A narrow fixed glass panel beside a door.
Why it matters: It adds light to an entry and must be approved together with the door.
- Small missile impact (SMI)
A test with small steel balls that simulate roof gravel, followed by wind-pressure cycles.
Why it matters: Openings more than 30 ft above ground, such as high-rise condos, need small-missile protection. Some products are approved for both.
- Solar Heat Gain Coefficient (SHGC)
The share of the sun’s heat that passes through the window, from 0 to 1. Lower numbers let in less heat.
Why it matters: In Florida’s climate, SHGC is often the energy number that matters most for comfort and cooling costs.
- Tempered glass
Glass treated with heat to be about four times stronger than ordinary glass. When it breaks, it crumbles into small, blunt pieces.
Why it matters: It is used as the outer pane of many insulated units and wherever safety glass is required.
- Thermally broken frame
An aluminum frame split by an insulating strip so heat cannot travel straight through the metal.
Why it matters: Aluminum conducts heat well. A thermal break keeps the inside of the frame cooler and improves energy performance.
- Transom
A fixed glass panel above a door or window.
Why it matters: It adds height and light, and it must be approved as part of the assembly.
- U-factor
How much heat passes through the whole window. Lower numbers mean better insulation.
Why it matters: A lower U-factor keeps cooled air in, which matters most with insulated glass.
- Visible light transmittance (VLT)
The share of visible daylight that passes through the glass. Higher numbers mean brighter rooms.
Why it matters: It shows the trade-off between a darker, cooler tint and natural light.
- XO, OX and XOX
Codes for sliding layouts seen from outside: X is a panel that slides and O is a fixed panel.
Why it matters: The layout decides which side opens, which helps you plan furniture and walkways.
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