𝗧𝗿𝗶𝗽𝗹𝗲 𝗚𝗹𝗮𝘇𝗶𝗻𝗴 𝗮𝗻𝗱 𝗣𝗮𝘀𝘀𝗶𝘃𝗵𝗮𝘂𝘀 𝗗𝗲𝘀𝗶𝗴𝗻 – 𝗮 𝘀𝗶𝗴𝗻𝗶𝗳𝗶𝗰𝗮𝗻𝘁 𝗰𝗼𝗺𝗯𝗶𝗻𝗮𝘁𝗶𝗼𝗻 𝗶𝗻 𝘁𝗵𝗲 𝗱𝗲𝘀𝗶𝗴𝗻 𝗼𝗳 𝗲𝗻𝗲𝗿𝗴𝘆 𝗲𝗳𝗳𝗶𝗰𝗶𝗲𝗻𝘁 𝗯𝘂𝗶𝗹𝗱𝗶𝗻𝗴𝘀

For a Passivhaus project to be successfully certified, it is generally a non-negotiable to use triple-glazed windows in the design of the building envelope. The reason being, that triple glazing provides remarkably high levels of thermal performance – an ever-constant requirement for achieving successful Passivhaus design.

In the building industry, ‘U-values’ (or thermal transmittance values) are generally used to rate the thermal performance of floor, wall, roof, and window components. A U-value is a measure of how well a building, or building element, resists heat transfer, or how easily heat can pass through it.

The lower the U -value, the better the component performs when insulating a building, or less heat is being lost through it. You will see the units for U-values written as ‘W/(m2 ·K)’ = ‘Watts per square metre per Kelvin’.

Part L of the UK building regulations requires the limiting U-values for new windows in buildings to be a maximum of 1.6 W/(m²K). The Passive House Institute requires that Passivhaus standards achieve a much better window performance, where ‘for most cool-temperate climates, this means a U-value of 0.80 W/(m²K) or less, with G-values around 50%’.

Triple glazing has the capability of achieving exceptionally low U-Values. When compared against double-glazed windows, the u-value differences are significant, performing approximately 100% better than double glazing.

But how does this work? A triple-glazed window is just that – three panes of glass, each one separated by voids filled with an Argon or Krypton Gas. This combination significantly prevents heat transfer.

When specifying windows for Passivhaus projects it is important to consider the overall window ‘installed U-value’, which includes the thermal performance of the frame and the glass in the wall. It is also particularly important to consider the 'G-values' of the glass. The G-value is the amount of solar transmittance through the glass where a high-performance glazing typically achieves 0.5 / 50%.

To add to this, while performing very well thermally, triple glazed windows also provide high levels of sound proofing, which many building owners consider as a huge advantage in the design of their building. This aspect significantly enhances noise reduction, improving concentration levels and living standards.

Ascertified PH designers, we at Lytle Associates Architects can help you realisethese standards. Contact us today:

☎️ (+44) 01483 301 661

📨 prawsthorn@lytle-associates.com

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