Frequently Asked Questions

General Questions

What is a U-value?

The U-value indicates the thermal insulation value of a product (here vacuum glass). The lower the U-value of a product, the better this product insulates. BENGglas has the lowest U-value in the world out of all types of insulating glass (U=0.4) and thus offers the best thermal insulation.

What is the advantage of tempered glass?

BENGglas is the only vacuum glass in the world that is fully toughened. The advantages of this are that it is 5x stronger than (regular) untempered glass, there is no risk of thermal breakage and it is injury safe.

What is injury safe?

BENGglas vacuum glass is always tempered and therefore injury-safe. With safety glass, only small pieces of glass will fall down when broken. These small pieces cannot cause serious injury.

Why are there spacers between the glass?

To prevent the glass plates from being pressed against each other due to the vacuum, microscopic spacers have been placed over the entire glass surface.

BENGglas has the smallest and fewest spacers of all brands and available types of vacuum insulating glass.

What is the noise reduction value?

The noise reduction value is dB=36.

Regular sound-reducing glass is very thick and therefore does not fit in every type of frame. If you are looking for sound-insulating glass and it also needs to be thin, there is only 1 possible solution and that is vacuum glass.

Is there a decrease in U-value over the years?

There is no decrease in U-value over the years – it remains at 0.4. Even if the glass is placed at an angle, there is no loss of insulation value.

Is condensation possible?

Outdated insulating glass has a high U-value (insulation value), which could cause condensation to form on the inside of the glass. Because the U-value has been greatly improved, condensation will only occur on the outside during the ‘condensation’ season. This has no disturbing effect and does not damage the panel.

Why choose BENGglas?

Compared to traditional forms of insulating glass, BENGglas has an insulation value that is many times better. In fact, with its U-value of 0.4, BENGglas offers the best insulating glass in the world.

BENGglas is the only brand that supplies its insulating glass with tempering as standard and is very competitively priced compared to ordinary vacuum glass. Moreover, BENGglas has fewer and smaller spacers than its competitors.

What does BENGglas cost?

The initial investment of BENGglas is higher than with traditional insulating glass or triple glazing. But due to the much better insulation value – which does NOT fall back over the years – you will quickly earn it back. The payback period will of course depend on energy prices, which will certainly rise in the future.

The exact price of BENGglas will depend on the thickness, size, installation height, etc. We can provide you with a quote after an initial assessment of your house or project. 

How do I get a quote?

You can get a quote by calling us, emailing us or filling in the contact form and we will get back to you. 

Are you an architect, project developer or otherwise professionally active in the real estate or renovation market?

Would you like to receive more in-depth technical information, a project price estimate or samples?

Please call us on +353 -1-454-2544 or send an email to or fill in our contact form

About BENGglas

Why choose BENGglas?

BENGglas has an insulation value that is many times better than traditional forms of insulating glass. In fact, BENGglas offers – with its U-value of 0.4 – the best insulating glass in the world.

BENGglas is the only supplier of vacuum glass to offer its glass standard as tempered and is very competitively priced. Furthermore, BENG glass has fewer and smaller spacers than its competitors.

What sizes are available?

BENGglas starts with a thickness of 6.3mm, rising to 20.3mm in total. Further thickening with e.g. insulation glass is possible.

Can shaped windows be supplied?

Yes, with 1, 2 or 3 slanted sides, triangles, circles, arches, etc. What is not possible are curved panels.

Does BENGglas fit in all types of windows?

Yes. BENGglas fits perfectly into old window frames because it is very thin (from 6.3mm). However, BENGglas is also an excellent product for new buildings with wooden, plastic or aluminium window frames.

What are the minimum and maximum sizes of BENGglas?

The smallest size of BENG glass is 300 x 300mm. Smaller is possible if 1 side is larger than 300mm.

The largest vacuum glass size available is 1750 x 3000mm.

The larger the glass surface, the thicker the glass structure will be.

What types are available?

In addition to the standard version, there are options for extra-clear, extra-sunproof, frosted and laminated tempered vacuum glass. A dirt-resistant coating can also be applied as an option.

Vacuum evacuation port (valve) in sight?

BENGglas has 4 types of vacuum glass in its range: BENGglas BASIC, BENGglas, BENGglas PRO and BENGglas+.

BENGglas and BENGglas+ have a cap in the bottom corner. BENGglas BASIC and BENGglas PRO do not have this.

BENGglas and renovation?

Because the tempered vacuum glass is extremely thin (from 6.3mm), it is an excellent product for renovation. You use your old window frames and only need to exchange the old glass for BENGglas. In this way, you can provide your period house or building with extremely good insulating glass.

Payment and Warranty

What is the warranty period?

BENGglas has a warranty period of 15 years, a tested lifespan of 25 years and an expected lifespan of 50 years. In comparison, traditional insulating glass warranties are generally for a term of only 10 years.

More Information


We are using cookies to give you the best experience. You can find out more about which cookies we are using or switch them off in privacy settings.
AcceptPrivacy Settings


  • Privacy Policy

Privacy Policy

We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. By clicking “Accept All”, you consent to the use of these cookies. You may visit our privacy page for more information.