Concepts

The U-value indicates how well glass insulates. Simply put: the lower the U-value, the better the glass keeps heat in in the winter - and out in the summer. So you save on your energy bill and increase your living comfort.
The U-value is influenced by many factors, such as:

• The coating on the glass
• The filling between the glass layers (e.g. air, gas or vacuum)
• The cavity width - i.e. the space between the glass layers

How well does BENG glass score compared to other types of glass?
Here is an overview of the average U-values per type of glass:

• Single-glazing: 5.8 (insulation? Barely.).
• Double glazing (Thermopane): 2.8
• HR++ glass: 1,10
• HR++ / Triple glass: 0,70
• Other vacuum glass: between 0.45 and 0.70
• BENG glass: from 0.35 to 0.50

In short: BENG glass has by far the best insulation value of all.
So you save extra on your energy bill!

*U-values measured according to standards EN 674:2011 and ISO 19916-1:2018 by ift Rosenheim (2025).

BENG glass has an exceptionally low U-value starting at 0.35 W/m²K, which means that the glass insulates extremely well. By comparison, this is two times better than triple glazing (around 0.70 W/m²K) and three times better than standard HR++ glass (around 1.10 W/m²K). Thanks to this excellent insulation value, BENG glass saves significantly on energy costs and helps make your home more comfortable and sustainable. Moreover, this U-value is substantiated by reliable European test institutes such as ift Rosenheim and TÜV Rheinland, with recent reports from 2025 that you can consult in our knowledge base. So you can be sure that you are choosing quality and maximum energy savings.

When it comes to heat loss through your windows, it's not just about the glass itself. The transition from the glass to the frame also plays a big role. And that's exactly what the PSI value is about.

The PSI value shows the heat loss per meter of the edge of the window - exactly where the glass meets the frame. The lower that value, the less heat is lost along the edges of your window.
The PSI value is measured at a temperature difference of 1°C between inside and outside, per linear meter. In other words, how well does your window keep out the cold, even at the edges?
A low PSI value = less heat loss = lower energy costs.

Sound attenuation is expressed as a so-called Rw (C; Ctr) value. What exactly does it mean?

• Rw is the standard noise reduction value in decibels (dB).
• C is a correction for noise with many high-pitched sounds, such as children playing or fast road traffic.
• Ctr is a correction for noise with lots of low tones, such as humming city traffic or a nearby club.

The higher the Rw value, the better the glass blocks sound. But if you have a lot of low-pitched noise (such as traffic or loud bass), the Rw + Ctr value says the most about the actual attenuation.

An example:

A value of Rw (C; Ctr) = 30 (-1; -4) means the glass attenuates 30 dB on average, but in practice:

• 29 dB at higher tones (Rw + C)
• 26 dB at low tones (Rw + Ctr)

What are the scores for each glass type?

• HR++: 31 dB (-1; -4)
• HR++: 33 dB (-2; -6)
• BENG glass: 36 dB (-2; -3)

And you can see this in practice:

• HR++ glass attenuates between 30 and 37 dB, depending on pitch.
• HR++ is between 31 and 27 dB - less good at low tones.
• BENG glass remains stable at 34 to 33 dB - so strong performance at all pitches.

In short:
With BENG glass, you not only choose top insulation against cold, but also peace of mind in your home.

The LTA (light admission factor) value indicates how much natural daylight comes in through the glass. The higher the value, the more light enters your home - and you notice it right away.
Daylight not only makes your home more pleasant to live in, it also helps save energy. Because the more light that comes in, the less often you have to turn on the lights.

More or just a little less light? You choose

Not every room needs the same amount of light. In a home or building with a lot of glass or direct sunlight, a lower LTA value may actually be pleasant. This way you avoid bright glare, overheating or discoloration of furniture and floors.
For this reason, BENG glass offers various glass variants - from clear to more sun-resistant - with high and lower LTA values, depending on the function of the space and the location of your facades.
Whatever you choose: your insulation is always top notch, with a U-value of up to 0.35.

Want to know what best suits your plans? We are happy to think along with you.

The G-value (solar factor) indicates how much solar heat comes in through the glass. So: how much free heat from the sun do you actually feel inside?
Good to know: whatever G-value you choose, with BENG glass you are always assured of excellent insulation - much better than HR++ or triple glazing.
And it shows: your house loses less heat, stays warmer for longer and you don't have to heat as much. This makes a big difference to your energy bill, especially in the winter or in older homes.

What does differ is how much solar heat and daylight you let in.

• Higher G-value → more solar heat inside. Great for bright rooms or cold facades.
• Lower G-value → more solar heat blocked. Ideal for lots of glass, warm rooms or summer sun.

You choose what suits you
BENG glass comes in several variants, each with its own balance of light, heat and solar control.

Do you want extra daylight? More sun protection? Or just a little of both? You decide what's important - and whatever you choose:

• it simply fits into your existing window frames
• It is slim, light and super insulating
• it contributes to a more comfortable indoor climate

Below are the types that BENG glass offers and them G-values:

• BENGglas® Extra clear: 0.68
• BENGglas® Single Coated: 0.58
• BENGglas® Double Coated: 0.39
• BENGglas® Triple Coated: 0.33
• BENGglas® Solar Control: 0.29
• BENGglas® Monu: 0.68
• BENGglas® Monu Restover: 0.68

Looking for a different G-value? Even then we'd be happy to think with you. Please contact us to inquire about the possibilities.

Injury-safe glass means that when broken, the glass does not break into large, sharp pieces, but into small, unsharp grains. This greatly reduces the risk of injury - extra nice for safety in your home or building.

• Tempered glass (injury-safe): when broken, falls into small, round grains that are not sharp.
• Unhardened glass: breaks into large, sharp shards that can be dangerous.

At BENGglas, we think safety is very important. This is why our entire range is tempered as standard and therefore injury safe.

Tempered vacuum glass is vacuum glass in which both sheets of glass are tempered. This means that the glass is first heated to a very high temperature and then cooled at lightning speed. This process creates a permanent, internal stress that makes the glass up to five times stronger than ordinary, untoughened glass.

Whereas untoughened vacuum glass is more fragile and susceptible to breakage, toughened vacuum glass, like BENG glass, can handle large loads, pressure differences and temperature changes effortlessly. This is why toughened vacuum glass is also called safety glass (injury-safe glass).

Why is toughened vacuum glass so much stronger?

The following happens during the toughening process:

• The glass is heated evenly to about 650 °C
• The surface is then cooled very quickly
• The outer layers tighten
• The inner core cools slowly and remains under tension

That combination creates a glass structure that:

• is 5× stronger
• Is much more resistant to impact and pressure
• tolerates temperature variations without breaking
• remains stable and retains its shape - essential for vacuum glass

This virtually eliminates thermal breakage - glass breakage due to temperature stresses - in BENG glass.

How does tempered vacuum glass break (injury safe)?

If tempered vacuum glass does break, it does not fall into sharp, dangerous shards.
The glass disintegrates into small pieces, minimizing the risk of cuts.

Why do some brands still choose untoughened vacuum glass?

Unhardened vacuum glass is easier to produce, but :

• is more susceptible to thermal breakage
• is not injury-safe
• can handle less pressure
• is less suitable for large windows

So tempered vacuum glass is a higher quality grade.

At BENG glass you always get toughened vacuum glass

Many brands still supply untoughened vacuum glass.
BENG glass never does. With us, toughened, injury-safe vacuum glass is the standard - at no extra charge.

That means:

• more safety
• more stability
• higher durability
• better performance
• fewer risks

Laminated BENG glass offers tremendous possibilities: you can choose from three types of films (EVA, PVB or SentryGlas Plus) and a virtually unlimited range of counter glasses.

All film types ensure that no shards will come loose if broken. But it doesn't stop there - you benefit from many more smart advantages. Each film type has unique properties, giving the window - in addition to the superior insulation value of BENG glass - many extras, such as:

• fall-through safety - well safe at height, for all building functions
• Break-in retardation -not easy to get through
• extra sound insulation - from -36 dB to -39 dB or more, audibly quieter
• Better UV protection - your furniture stays nice longer
• colors and patterned glass - your window will completely change appearance

How you want to put together your laminated window is completely up to you. Think of patterned glass for a unique look, or additional films for maximum safety. Let us know what you are looking for - and we will be happy to think along with you.

At BENGglas®, transparency and reliability are paramount. Therefore, all our vacuum glass is tested according to the appropriate European standard: EN674:2011-06 or ISO 19916-1:2018-10.

The widely used standard EN673 expressly excludes vacuum glass. This method does not take into account the unique properties of vacuum glass, such as the vacuum space, micropillars and specific edge sealing. This can lead to U-values that appear too positive.

Testing according to EN674 gives us a realistic and accurate picture of actual thermal performance. No assumptions, no overestimates - just real results.

With BENGglas®, you therefore know exactly where you stand: high-quality, tested solutions that meet the highest standards.

Want to know more? Then discover the differences between EN 673 and EN 674 in our blog!