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A LUTUM-pitched roof is cool and sustainable. In the world of sustainable construction, where energy efficiency and environmental consciousness are paramount, it is vital to understand the important role of roofing in maximising the energy efficiency of a building and how it mitigates the negative impacts on the atmosphere.

Does colour really matter?

 

The first level of defence is the material’s ability to reflect visible solar energy (Solar Reflectance). The remaining energy (invisible range) is absorbed by a roof (Solar Absoprtance). A value of 0 indicates that none of the solar radiation is absorbed, whilst a value of 1 indicates that a roof absorbs 100% of solar radiation. For example, LUTUM’s Pearl colour profile has a Solar Reflectance level of 0.65, meaning it reflects 65% of solar energy.

Generally speaking, light-toned colours reflect more of the sun’s energy compared to dark colours. But colour and Solar Reflectance (SR) levels are far from being the only factors for a truly sustainable, energy-efficient roof. Another vital determinator is the material’s Emittance (or emissivity), the ability to radiate absorbed solar range (without transforming into heat). It’s measured similarly to SR, between 0 and 1.

Why Emittance is key for a cool roof?

 

The higher the emittance, the more readily the roof surface will radiate the energy back to the atmosphere, keeping a house cooler. Cool roofs are highly emissive to maximise the amount of heat that is radiated away. 

LUTUM Concrete, Terracotta and Designer Ceramic roof tiles are inherently high in emittance, varying between 0.86 and 0.95 making them an excellent choice for hot climates.

High Emittance helps a surface cool by preventing absorbed heat from entering a building all at once and radiating the heat more efficiently maintaining stable internal temperatures without heating up the atmosphere.

Generally speaking, building materials with low Emittance such as metallic materials let the majority of solar energy penetrate a roof and therefore severely heat up the dwelling for longer periods of time.

Roofs with high Solar Reflectance and Emittance levels tend to perform best in hot climates as they absorb less heat and radiate it effectively. Combining these two metrics together in a formula provides an index called Solar Reflectance Index (SRI).

 

Solar Reflectance Index.

 

Solar Reflectance Index is revolutionising the way we think about thermal performance and energy conservation. This innovative index ranges from 0 to 100, with higher values indicating greater reflectivity and lower heat absorption. 

With a 3-year classification of SRI, the index provides even more precision accounting for the ageing and colour deterioration of the material. It is important to note that LUTUM roof tiles’ high emittance levels are an inherent ability of concrete, terracotta and ceramic. Unlike the coating on sheet metal, which if damaged, would drastically lessen the SRI.

Why a LUTUM-pitched roof is cool and sustainable 
Why a LUTUM-pitched roof is cool and sustainable 
Why a LUTUM-pitched roof is cool and sustainable 
Why a LUTUM-pitched roof is cool and sustainable 
Why a LUTUM-pitched roof is cool and sustainable 

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Sustainability

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A LUTUM-pitched roof is cool and sustainable. In the world of sustainable construction, where energy…
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Sustainability

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