7830 Byron Dr Ste 4, West Palm Beach, FL 33404

Reference

Glass options and ratings
what the choices actually change

For a South Florida house the glass decision comes down to four questions. Does it have to be impact rated, how clear do you want it, how much heat should it stop, and how private does it need to be. Everything below answers one of those.

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Florida license

SCC131154568

Counties served

Martin, Palm Beach, Broward, Miami-Dade

Residential estimates

Same day

Page type

Reference, not a sales pitch

Build

What the glass is made of

This is the first fork and it decides most of the rest. Everything else, tint, coating and etching, gets applied to one of these.

Monolithic tempered

One ply, heat treated so it is stronger and so it breaks into small blunt pieces instead of shards. This is shower glass, railing glass and partition glass.

Laminated

Two plies bonded to a plastic interlayer. When it breaks the pieces stay stuck to the interlayer. That is the whole principle impact glazing is built on: the glass can break and still stay in the frame.

Insulated

Two lites separated by a sealed cavity, with a spacer around the edge holding them apart. The cavity is what slows heat transfer, and the seal around that spacer is what fails when a unit fogs.

And then there is the one you probably want

Laminated insulated is both at once, and it is what most impact windows in Florida actually are: an outer laminated lite that carries the impact requirement, a sealed cavity, and an inner lite. You are not choosing between the two above. You are usually buying both.

Reference

The four builds, side by side

Kept as a table because this is the part people come back to check.

Monolithic tempered

One ply, heat treated so it is stronger and so it breaks into small blunt pieces instead of shards. This is shower glass, railing glass and partition glass.

Laminated

Two plies bonded to a plastic interlayer. When it breaks, the pieces stay stuck to the interlayer. That is the whole principle impact glazing is built on: the glass can break and still stay in the frame.

Insulated

Two lites separated by a sealed cavity with a spacer around the edge. The cavity is what slows heat transfer. This is the unit that fogs if the seal ever fails.

Laminated insulated

Both at once, and what most impact windows in Florida actually are: an outer laminated lite for the impact requirement, a cavity, and an inner lite.

Acid etched glass: clear above, satin below. The etch is in the surface, not a film, so it does not peel and it cannot be scraped off.

Clarity and color

The five finishes we actually stock and order

These are the options on our own product pages, not a manufacturer’s full catalog.

Clear

Standard float glass. Look at the polished edge and you will see green. On a large pane, and on anything stacked or thick, that green reads.

Low iron

The iron that causes the green is removed. Almost colorless, and worth it wherever the edge is exposed or the glass is thick. Standard on high end shower and railing work.

Tinted

Bronze or gray in the glass body. Cuts glare and visible light, and changes the color of the light in the room. A design decision as much as a performance one.

Acid etched

The surface is etched to a soft even translucence. Light passes, detail does not. Used for privacy without losing the daylight.

Acid etched low iron

The same etch on low iron glass, so the finish stays neutral white instead of picking up a green cast.

Low-E coating

A microscopically thin metallic coating that reflects heat. It is designed to help reduce heat transfer compared with older uncoated single pane glass. How much depends on your orientation, your shading and the rest of your envelope.

Coatings and the numbers behind them

Low-E coatings, what the three numbers mean, and the tint the beach requires

A low-E coating is a stack of microscopically thin metal layers, usually silver, sputtered onto the glass in a vacuum. It lets visible light through and turns back the part of the sun’s energy you feel as heat. Solarban 70XL was the first triple silver version of that coating, which is why it can hold a lot of daylight and still block most of the heat.

Three numbers describe it, and they are the three you will see on a permit set or a manufacturer’s sheet:

Visible light transmittance is how much daylight comes through, as a percentage. Solar heat gain coefficient is the share of the sun’s energy that gets through, from 0 to 1, and lower is cooler. Light to solar gain is the first divided by the second: how much daylight you keep per unit of heat you let in. A higher ratio is a better coating.

Vitro published figures, 1 inch insulating unit
Glass	Visible light	Solar heat gain	Light to solar gain	Under the 45% turtle threshold
Solarban 60 with clear	70%	0.39	1.79	No
Solarban 70XL with clear	64%	0.27	2.37	No
Solarbronze with Solarban 70XL	38%	0.26	1.46	Yes
Solargray with Solarban 70XL	32%	0.24	1.33	Yes

Solarban is made by Vitro Architectural Glass, formerly PPG. These are Vitro’s published figures for a one inch insulating unit with a half inch airspace and two quarter inch lites. Most of what we install is nine sixteenths laminated impact, which is a different buildup and carries different numbers. We give you the figures for the exact glass on your quote, not these.

The 45 percent rule on the beach

Florida’s model lighting ordinance for marine turtle protection, Rule 62B-55 of the Florida Administrative Code, defines tinted glass as glass with an inside to outside light transmittance of 45 percent or less, and the coastal construction section of the Florida Building Code points at the same standard. It applies where interior light is visible from the nesting beach.

In Palm Beach County the requirement sits in the Unified Land Development Code and Environmental Resources Management enforces it, with nesting season running March 1 through October 31. Martin, Broward and Miami-Dade each have their own ordinance, and individual coastal towns can be stricter than the county. The building department with jurisdiction has the last word, so we confirm the number with them before the glass is released.

The part that rarely gets said out loud: the gray that puts you under 45 percent is the same coated product, and it cuts the solar heat gain at the same time. Solargray with Solarban 70XL reads 32 percent visible light and 0.24 solar heat gain, against 64 percent and 0.27 for the clear version. On the beach the turtle rule and the power bill pull in the same direction.

Reading a manufacturer sheet without getting fooled

Every published number is tied to a specific makeup. Change the thickness, the airspace, the interlayer or which surface the coating sits on and the numbers move. A figure quoted for a one inch insulating unit does not describe a nine sixteenths laminated lite, even with the same coating name on it.

So when you compare two quotes, compare the buildup, not the brand. Ask what the glass actually is, then ask for that makeup’s numbers. If a quote names a coating with no buildup next to it, it has not told you anything yet.

In practice

What the build choice looks like once it is in

The spec sheet stops mattering the day it is installed. What you live with after that is the light, the view and how quiet the room is, and those come from the glass build as much as from the frame around it.

Ratings

The numbers that show up on your permit

You do not need to memorize these. You do need to know that they exist, because the approval has to cover your opening before anyone can pull a permit for it.

Large Missile Impact

The assembly is fired at with a nine pound piece of lumber and then cycled under pressure. Tested to ASTM E1886 and ASTM E1996, and in the High Velocity Hurricane Zone to TAS 201, 202 and 203.

Design Pressure, DP

How much positive and negative pressure the assembly is rated to take. Your engineer calculates what the wall needs and the product has to meet or beat it.

Miami-Dade Notice of Acceptance

The approval used in the High Velocity Hurricane Zone, which is Miami-Dade and Broward. Each NOA covers specific sizes and configurations.

Florida Product Approval

The statewide route, accepted in Martin and Palm Beach. Same idea, different administering body.

U-factor and SHGC

The two thermal numbers on the NFRC label. U-factor is how much heat moves through. SHGC is how much solar heat gets in. Lower is less, for both.

Safety glazing

The code requires tempered or laminated glass in specific locations: doors, next to doors, near the floor, around tubs and pools. It is not optional and it is not a upgrade.

In practice

What this means for four common jobs

Replacing windows on the coast

Laminated insulated with a Low-E coating, impact rated, with the approval that matches your county. This is the default and there is not much to decide beyond tint and frame color.

A frameless shower

Tempered, and low iron if the walls are white or pale stone. On clear glass the green edge is visible against white and people notice it after the fact.

A glass railing

Tempered or laminated depending on whether there is a top cap, and low iron when the run is long and you see edge after edge.

An interior partition

Tempered, and acid etched where you want light without a fishbowl. No impact requirement, because it is not in the building envelope.

Impact windows

The product side of everything on this page.

Open

Frameless shower doors

Where low iron earns its money.

Open

Permits and approvals

How the approval numbers turn into a closed permit.

Open

Not sure

Ask before you order

Glass is easy to get wrong once and expensive to get wrong twice. Tell us the room, the orientation and what is bothering you about the light, and we will tell you what we would specify.

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See impact windows