Triple Glazing FAQs With Internorm Windows

4th November 2025

Triple glazing offers superior thermal efficiency, comfort, and noise reduction compared to traditional double glazing. By using three panes of glass separated by insulating gas-filled cavities, it significantly reduces heat loss, helping to lower energy bills and improve a building’s overall energy performance. The extra pane also enhances sound insulation, creating a quieter indoor environment, while minimising cold spots and condensation on window surfaces. In addition, triple glazing improves security through stronger glass construction, making it a smart long-term investment for sustainable, comfortable, and secure living or working spaces.

What difference does triple glazing make to acoustic performance?
Triple glazing can improve acoustic performance compared to double glazing. The extra pane of glass and the insulating layers of gas between the glass panes in triple glazing help to reduce the transmission of sound waves through the windows, resulting in improved acoustic insulation. The ability of a window to reduce noise is measured by its sound reduction index (SRI), which is expressed in decibels (dB). A higher SRI means that the window provides better sound insulation. Triple glazing typically has a higher SRI than double glazing, as it provides an additional barrier to block sound waves.

The effectiveness of triple glazing in reducing noise transmission depends on several factors, such as the thickness of the glass panes, the distance between the panes, and the type of gas used to fill the space between the panes. A well-designed triple glazing unit can provide significant noise reduction, making it an excellent choice for buildings located in noisy environments, such as near busy roads or airports.

Do Internorm windows and doors come with triple glazing as standard?
Yes, Internorm products are supplied with triple glazing as standard. This ensures excellent thermal insulation, noise reduction and enhanced security.

What makes Internorm triple-glazed windows important in coastal self-builds?
Coastal properties quite often have to withstand extreme weather conditions. Internorm triple glazing improves thermal efficiency and air tightness due to its triple gasket construction. Internorm high-performance triple glazed windows and doors also offer outstanding noise reduction and enhance security, making them perfect for homes with large glazed areas or in challenging coastal environments. The external powder-coated aluminium can be anodised for coastal homes to avoid corrosion, therefore making Internorm triple-glazed windows some of the best windows and doors for seaside properties.

Are Internorm triple glazed windows and doors suitable for Passivhaus?
Absolutely! The Internorm product range has been used successfully in Passivhaus projects for many years. In fact, they are the go-to windows and doors for Passivhaus self builds, low energy and Eco Homes, as well as retrofits due to their outstanding quality, thermal efficiency, insulated frames, air tightness and durability, making them the ideal solution for anyone looking to create a sustainable Passivhaus home.

Why are Internorm triple-glazed windows and doors ideal for Passivhaus projects?
Internorm triple-glazed windows and doors combine timber-aluminium or uPVC-aluminium construction with integrated frame insulation and a triple gasket system. Achieving u-values below 0.8 W/(m²K) and exceptional airtightness, they provide high thermal efficiency, helping Passivhaus projects meet strict energy standards.

Why choose Internorm triple-glazed windows for a Passivhaus project?
Internorm triple-glazed windows and doors deliver top-tier thermal efficiency and airtightness. Their timber-aluminium and uPVC-aluminium designs include triple gaskets and insulated frames, achieving u-values below 0.8 W/(m²K). This makes them ideal for energy efficient Passivhaus homes requiring long-term comfort and low heat loss. Together with essential external shading solutions, Internorm offers the most complete product range for Passivhaus and EnerPHit projects.

Are triple glazed windows better than double glazed?
Yes, although you need to do your homework, as not all triple glazing is the same in quality and performance. Triple glazed windows offer significantly higher thermal efficiency, improved acoustic insulation, and enhanced comfort compared to double glazing. Internorm’s triple-glazed system was introduced as early as 1979, so it’s nothing new.

Internorm high-performance triple glazed windows and doors are made from premium components, raw materials, and hardware. Combined with triple gaskets, insulated frames, as well as all-round bonded glazing, these timber-aluminium and uPVC-aluminium products minimise heat loss and condensation, creating a quieter, warmer, and more energy-efficient living environment.

Is triple glazing worth the investment?
Absolutely. While the initial cost is higher, Internorm triple glazing delivers measurable long-term savings through reduced heating demand and lower energy bills. Combined with improved home comfort, durability, and property value, it’s an investment in both performance and peace of mind.

What is the payback time for triple glazed windows?
The payback period varies by home size and insulation, but Internorm triple-glazed windows typically offset their cost within 5–10 years through lower energy consumption. Their long lifespan and minimal maintenance make them one of the most cost-effective upgrades for energy and sustainability-conscious homeowners.

How much lower will my energy bill be if I get triple glazing?
Upgrading to Internorm’s triple-glazed windows can reduce annual heating costs by up to 50%, sometimes more, depending on property type and insulation levels. With U-values below 0.8 W/(m²K) and airtight, insulated frame construction, Internorm windows retain more heat, cutting both energy bills and carbon emissions, making them a sustainable solution for self build, renovation and Passivhaus projects.

What is the best triple glazed window?
The best triple-glazed window combines energy efficiency, aesthetics, and precision engineering- qualities that define Internorm’s timber-aluminium and uPVC-aluminium systems. Models like the HF 410 and KF 520 achieve ultra-low U-values, sleek design lines, and exceptional performance for both contemporary and traditional architecture.

Popular for Passivhaus self builds and retrofits, the Internorm alu-clad high-performance product range also includes essential external shading solutions to avoid overheating during summer months, as well as fly screens to keep bugs out. In addition to tilt & turn windows, Internorm offers large lift & slide doors, Panorama fixed glazing, glass-to-glass corners, entrance doors, as well as Juliette balconies.

What difference in quality is there between triple glazed window brands?
Quality varies widely between manufacturers. Internorm windows are engineered in Austria to exacting standards, offering consistent airtightness, superior materials, and longevity proven over decades. Many lower-cost alternatives lack this precision manufacturing and insulation technology, leading to reduced efficiency and durability.

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