Internorm Senior Commercial Manager Barry Miller reveals how the company is leading the fenestration industry with its focus on high performance products and constant innovation

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HF400 is Internorm’s new iCore timber- framed, aluminium-clad triple-glazed window system with slim sightlines and excellent insulation properties as low as 0.7W/m²K and impressive noise reduction up to 45dB

Today, the central focus is to create a comfortable living environment that is low energy and well insulated against the ever increasing cost of utilities. Getting this right relies on a range of design and construction factors, but the key piece of the puzzle is to take a fabric-first approach that seeks to minimise energy usage rather than ‘bolting’ on renewable technologies. This is where the Passive House principles come in.

The Passive House building code has set the benchmark in creating a comfortable living environment with extremely low energy bills, along with maximising natural energy sources. This concept of optimising the internal climate – by providing a highly insulated airtight structural shell that allows sufficient heat to be supplied by solar gain, appliances and the building’s occupants – is now driving new Building Regulations which we certainly hope will be published later this year.

Passive Hosue properties can deliver up to a 90 per cent saving in energy bills when compared to buildings constructed to current Building Regulations.Glazing plays a critical part in all buildings, but none more so than in energy- efficient ones. Perhaps the most obvious advantage is the free warmth that can be allowed into the building. But how much can be retained?

The thermal efficiency of materials used for the fabric of any building is stated as its U-value – a calculation of how much energy in Watts is lost per square metre per hour. When considering a modern insulated wall structure that provides an average U-value of 0.12W/m²K, the challenge is to achieve this value when using glass. With new technology, we can make glass units with a Ug-value of 0.5W/m²K, which is a significant change from the old days of single glazing, which typically had a Ug-value of 5.4!


Internorm’s new KF520 Upvc-framed, aluminium-clad triple-glazed window system features slimsight lines, frameless sash design and a unique secure-locking system. It also has excellent insulation properties, as low as 0.63W/m²K and impressive noise reduction up to 46dB.

Although not quite as insulating as a wall, glass does have the benefit of providing light, and most relevantly, heat through solar gain. Triple-glazing plays an important role in achieving low Ug values. Internorm now manufactures more than 80 per cent of its insulated glass units as triple-glazed.

One of the most detrimental losses of energy to any building is air loss. Current buildings can pass an air test with results no greater that an air loss of 10m³/h/m². Compare this to a Passive House air test requirements 0.6m³/h/m² (almost 18 times better). Windows and doors must be installed correctly and designed and manufactured to ensure the products can themselves adhere to these higher standards. As mentioned previously, the Building Regulations are being reviewed and it has been proposed to increase the requirements of such air tests to meet a maximum air loss of 3m³oh.

It is not just the glass unit that contributes to thermal performance, the window frame and glass spacers must also provide high levels of insulation along with all the other components, such as gaskets and sealants. At Internorm, our triple gasket system and ‘fix-a-round’ sealant between glass and frame ensure that excellent thermal and airtight performance figures are achieved and certified. Every Internorm unit is designed and manufactured by us in our state of the art factories in Austria. They are suited to low-energy projects, meeting todays drive to reduce carbon emissions.

Internorm has distribution partners across the UK and a commercial division to manage larger developments. It is pleased to announce its new product range this year, including new slimline timber frame aluminium-clad (HF400) and Upvc frame aluminium-clad (KF520) systems.

Contact Details
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