Green Roof Benefits on Energy Conservation

Sourced from Sourcable

Green roofs are becoming increasingly popular in many countries. People are starting to realize just how many advantages a green roof has over a standard roof. Households and big companies are recognizing its benefits and incorporating it into their homes and buildings. So, how can you actually benefit on energy conservation from a green roof?
In short, green roofs are vegetated roof surfaces, meaning the roofs are partially or completely covered with growing plants. Their positive impact is dual: they contribute to the preservation of a building’s roof surface and provide significant environmental benefits.

Conventional roofs don’t help the energy balance in a building, while they neither help the immediate environment. Buildings with poor insulation and ventilation and conventional roofs tend to use more air conditioning, increasing the energy consumption.

On the other hand, there are three factors of a green roof that make a huge difference:

  • The plants and growing medium (engineered soil) of a green roof.
  • Transpiration – a process in which plants use their roots to take water, releasing it through the leaves.
  • Evaporation – the conversion of water from liquid to gas, which comes from both the plants and the growing medium.

All the good stuff

Benefits of having a green roof are numerous; however, the accent is on the reduced energy consumption. It’s possible to present them in the terms of a building and the neighborhood level.

At the building level, green roofs:

  • prolong the lifespan of the building’s roof
  • reduce the energy consumption, simultaneously reducing the costs for cooling. The National Research Council of Canada issued a publication on green roof benefits where it was stated that temperature fluctuations during spring and summer on a conventional roof were of the order of 45ºC, while a green roof provided the fluctuations in the order of 6ºC. According to German research, green roofs reduce winter bills 3-10%. Canadian research determined that summer savings on the top floor of a building with a green roof would be around 20%, while a two-storey building would have summer savings 10-12%.
  • improve aesthetics of the building.

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