But besides the aesthetic benefits have you ever thought that wall comprising plants could be used as acoustic insulation? Researchers have concluded that green walls offer great potential for absorbing noise, but do not deny the fact that they can be both costly and difficult to maintain.
Living walls are made up of plant modules: the plants are inserted into polyurethane boxes and are maintained by means of organic irrigation, in other words, they are fed and watered by means of a system similar to the hydroponic one used in greenhouses. It is not easy to grow plants this way or to insert them into a wall.
A noise absorption test was carried out in a reverberation chamber - a chamber the walls of which are fitted with materials that reflect noise of the same type in all directions- using a range of frequencies. Green walls have thus been found to perform very well in high as well as low frequencies with respect to noise reduction, whereas other materials used in buildings only perform well at either high or low frequencies.
The way green walls may behave as acoustic insulation was also studied: plant modules were fitted onto a laboratory wall and the level of noise insulation was measured. The conclusion reached was that with some slight improvements, like increasing the mass of the modules or covering the space between them, the system can be made more effective and, as a result, the green walls could be suitable for acoustic insulation.
Improved air quality
Living green walls are natural air-filters, creating a cleaner, more invigorating environment. People are often exposed to air toxins in their work or living environment such as formaldehyde, carbon monoxide and benzene. Living green walls metabolize harmful toxins while releasing oxygen into the workplace air, much like plants but on a much larger scale.
Green wall systems can help to protect a building’s façade and extend its life, acting as an effective shield to heavy rain and hail and helping to protect from the damaging effects of UV light.
Moreover, in areas where graffiti is a potential problem, green walls can act as an effective deterrent, making the application of graffiti to the building structure almost impossible.
Energy cost reduction
The interior and exterior living green walls function to cool the air in the warmer summer months by a process known as “evapotranspiration.” A green wall used on appropriate elevations can reduce energy costs by both providing an additional layer of insulation in the winter (keeping heat in) and acting as a screen to the sun in the summer (keeping the building cool).
Exterior living green walls can reduce wall surface temperatures by as much as 50 degrees °F, according to researchers, resulting in significant energy savings and air conditioning costs.
Earning green certification points
The installation of living green walls can earn buildings Green Certification points which, in turn helps to increase a property’s value by creating a favorable perception of a structure with an improved carbon footprint.
They provide a greener image of towns and cities, improve the life quality of citizens, save energy, increase biodiversity, control rainwater, to lessen city noise and minimize waste and pollution. Besides they are attractive and cool. It is true that they are not exactly cheap to build and maintain, but with so many benefits, would you still mind paying an extra buck to live in a building with at least one green wall?