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U-Values – and why a low one is important

At English Oak Buildings, we’re proud to say that we create our own custom made Structural Insulated Panels (SIPs Panels) – in fact, we’ve been making them for over ten years – longer than any other oak frame manufacturer in the UK. We are also keen to point out that our SIPS have exceptionally low U-Values. But what does this actually mean?

Well, a U-Value, or U-Factor, measures how good a material is as an insulator. It indicates how much heat is lost through a particular thickness of a material, and takes into account the three main ways that heat loss occurs. These are conduction, convection and radiation. The lower the U Value, the better heat insulation a material provides.

For those that want an even more in depth look into U Values, here’s some facts from thegreenage.co.uk:

The environmental temperatures inside and outside a building play an important role when calculating the U-value of an element. If we imagine the inside surface of a 1 m² section of an external wall of a heated building in a cold climate, heat is flowing into this section by radiation from all parts of the inside the building and by convection from the air inside the building. So, additional thermal resistances should be taken into account associated with inside and outside surfaces of each element. These resistances are referred to as Rsi  and Rso respectively with common values 0.12Km²/W and 0.06Km²/W for the internal and external surfaces, respectively.”

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When SIPS are used for external walls and roof panels, they can achieve good U-Values because the insulation is part of the structure. When considering timber, it’s also important to think about Thermal Bridging. This is where a part of the structure has significantly higher heat transfer – it occurs whenever there is a break in the continuity of the insulation, such as junctions between walls and floors. Timber frames have excellent thermal performance due to the nature of the material, and also means they provide outstanding protection from the cold in winter and help maintain a cool house in the summer.

And it’s not just a way of saving money – although this will be a significant help to those electricity bills over time. It also helps when considering the aesthetics of a build. Timber walls can have superb thermal insulation with a relatively slim thickness. Thicker walls cost more, reduce the useable floor space, and also require more energy to manufacture, meaning they are less environmentally conscious.

Friendly on your purse, the environment and space-saving?? Timber frames are the way forward!


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