Ever since the Romans first added glass in their window openings around 100 AD, designers and builders have strived to take windows beyond their humble beginnings as thick, small, curved, fixed pieces with little-to-no visibility.
Today we’re inundated with many different window types to meet the requirements of both commercial and residential projects.
Two viable options typically considered include laminated glass windows and insulated glass units. Laminated glass windows are sought after for their impact resistance. Insulated glass units are renowned for their energy efficiency.
Both window types have their benefits and drawbacks.
Is one better than the other for your project? Why not use both?
Comparing Laminated Glass Windows & IGUs
When considering types of glass windows for a project, many factors need to be taken into account. Do you need:
- Safety glass to protect against inclement weather?
- Sound abatement to dampen outside noise?
- Security glass to restrict entry?
- UV blockage to reduce heat transfer and sun damage?
- Thermal insulation for energy efficiency?
In a breakdown of which is best – laminated glass windows vs. insulated glass units (IGU) – a window’s specific needs must be weighed. Let’s break down the pros and cons of each:
- What is laminated glass & what are its benefits?
- What are insulated glass units & what are their benefits?
- Why not combine laminated and insulated glass?
What Is Laminated Glass & What Are Its Benefits?
Laminated glass (LG) is two or more layered panes of glass with a clear interlayer, typically polyvinyl butyral (PVB) resin, holding them together. Fabricators also use other resins for interlayers, including ethylene-vinyl acetate (EVA) for exterior applications, and thermoplastic polyurethane (TPU).
Because it’s bonded to an interlayer, laminated security glass holds together against heavy impacts, much more so than regular single-pane glass.
In the event it breaks, the shards usually remain bonded to the interlayer, posing less risk of injury. This makes it a safer alternative to regular glass.
In addition to their safety benefits, laminated glass windows provide:
- Enhanced security against break-ins – It’s highly impact-resistant and can withstand break-in attempts longer than regular glass.
- Protection from UV rays – LG’s interlayers resist ultraviolet radiation, protecting inhabitants and property from sun damage.
- Reduced heat transfer – LG’s interlayers help increase energy efficiency by reducing heat gain.
- Sound dampening – LG’s interlayers are almost as good at blocking sound waves as they are UV rays.
Depending on the job’s geographic location, it may be required to have laminated safety glass per safety codes. For example, anything close to the coast must be either tempered-laminated or hurricane-resistant laminated glass. Windborne debris protection has become a priority for health and safety code enforcers in areas where severe weather is common.
Custom laminated glass is a great choice for storefronts, too. Combining safety and security with soundproofing to block noises from busy streets, and UV resistance to keep merchandise in better condition, eliminating sun-bleaching.
Laminated glass is most often seen in cars. Thanks to its superior impact resistance it’s been the standard for windshields for a century. They reduce the incidence of car passenger ejection in accidents as well as injurious glass debris. Some higher-end vehicle manufacturers also use laminated glass side and rear windows to reduce road noise inside the vehicle.
What Are Insulated Glass Units & What Are Their Benefits?
Insulated Glass Units are usually two, but sometimes three, panes of glass separated by spacers. Manufacturers seal the IGU panes together with a spacer and pump in an inert gas – typically argon – to fill the space between the panes. The space can be left with just air, but an inert gas heavier than air slows down the transfer of heat between the glass panes.
In double-paned and triple-paned IGUs, the sheets of glass and layers of gas create a buffer of insulation. IGUs are the most common choice for energy-efficient windows. The gas layer diffuses heat transfer from entering a space in hot weather and leaving it in cold weather.
The more glass and gas layers, the more energy efficiency. If price wasn’t a factor, most builders would choose triple-pane IGUs. Because they use more materials, they are more expensive.
Along with high-performance energy efficiency, insulated windows offer:
- Safety – Compared to regular, single-pane glass, IGUs offer more protection from impacts.
- Noise reduction – The same gas that mitigates heat transfer reduces noise.
Why Not Combine Laminated and Insulated Glass?
Laminate glass windows take the award for safety, while insulated glass units are the clear winner in a competition for energy efficiency.
Luckily, designers and builders don’t have to choose between the two when they want the best of both worlds.
IGUs manufactured with an LG exterior-facing layer, or “outboard,” meet standards for both safety and energy efficiency.
While combining the two manufacturing processes leads to a higher cost overall, it also provides huge gains in:
- Energy savings – Over time, laminated glass IGUs pay for themselves in energy savings.
- Safety insurance – The investment in the impact resistance of LG pays off in inclement weather and attempted theft events.
- Acoustic peace – All those layers of glass create a sound barrier, protecting a space from noise pollution.
- UV protection – Whether it’s to protect merchandise, property, or people, LG’s interlayer dramatically reduces exposure to the sun’s rays.
What’s Your Next Glass Window Project?
Are you ready to start sketching out your next window project? Head here to learn more about putting your ideas in a format to communicate clearly with your commercial glass partner:
A Word On Coated Glass
Every window, whether it’s laminated glass or an IGU, can be improved with glass coating. Coated glass enhances a window’s performance with:
- Light reduction
- UV ray protection
- Energy efficiency
- Reflectivity
Coated glass isn’t a cure-all, but it helps. Say a customer wants the UV protection laminated glass offers, along with the energy efficiency of an IGU but can’t afford to integrate the two.
Low-e glass coating can be added to an IGU to attain similar results.
IGUs & Laminated Glass Windows: A Custom Solution
Depending on the project and its location, a custom solution may integrate laminated glass with the insulating method to meet the necessary standards.
However, not all projects allow for this (usually because of budget) and decisions must be made.
If your application is commercial, laminated glass may be crucial for safety.
On the other hand, if you’re installing residential windows, the energy efficiency of an IGU might be the best option.
Ultimately, if the budget numbers are available, combining the safety of laminated glass with the energy efficiency of IGUs creates juggernaut high-performance windows.
Ready to Get Started?
New Angle Beveling manufactures and distributes glass products for commercial installations across the Northeast. Contact us today to partner on your next commercial glass project.
(Editor's note: This article was originally published in February 2023 and was recently updated.)
