Green walls help buildings become more energy efficient which leads to a decrease in carbon emissions. They can also mitigate the urban heat island effect, absorb and filter stormwater, reduce pollution, act as carbon sinks and can provide habitats for biodiversity. From small garden projects to large industrial and commercial developments, the benefits of Green Wall systems are being realised across the public and private sectors.
In schools the systems can also deliver educational benefits, encouraging pupils to engage with the problems of carbon reduction and climate change and with broader ecological and environmental issues. Specific systems can be designed to suit a range of plant types, and as a habitat for different wildlife, whilst some large "farmscape" systems are being developed in north America to support to food grwing initiatives.
More information on the benefits of specific systems and green walls in general can be found at the following website:
Green walls or living walls protect buildings. Covering an exposed vertical surface with a green wall shields it from precipitation and wind as well as from harmful UV radiation and corrosive acid rain. This in turn increases the integrity and longevity of a building’s exterior. Temperature fluctuations over a building's lifetime can be damaging to organic construction materials in building façades. Green walls provide an additional layer of exterior insulation and thereby limit thermal fluctuations.
Improved Air Quality & Reduction of the Urban Heat Island Effect
Green walls mitigate air pollution levels by lowering extreme summer temperatures through photosynthesis, trapping particulate matter, and capturing gases.
The reintroduction of vegetation into urban environments promotes the occurrence of natural cooling processes, such as photosynthesis and evapotranspiration. With strategic placement of green walls, plants can create enough turbulence to break vertical airflow, which slows and cools down the air (Peck et al. 1999).
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). Green walls can reduce the temperature fluctuations at a wall's surface from a range of 10-60ºC to 5-30ºC, in turn limiting the movement of heat between building walls (Minke 1982). They cause this reduction by:
o Trapping a layer of air within the plant mass.
o Reducing ambient temperature via evapotranspiration and shading.
o Creating a buffer against wind during winter months.
Studies have shown that the leaves of plants attenuate sound by reflecting, refracting and absorbing acoustic energy in small amounts. The amount of noise reduction is proportional to the number of plants that are present in a room. Green walls contain such a large number of plants that the acoustics of a room can be substantially improved.
Plants and trees have been used for years as barriers against traffic and other urban noise pollution. Green walls built on the exteriors of buildings will do the same. They insulate against noise, vibrations and reduce sound penetration. In addition they help to absorb the echo bouncing off buildings and dampen the noise pollution of modern cities.
Health & Wellness
According to scientific reports carried out at American and European Universities, simply having a view of plants in a working environment give positive physiological responses. This translates into greater job statisfaction and productivity (Kaplan 2001)
A study carried out at Washington State University had participants' blood pressure and emotions monitored while completing a simple, timed computer task in the presence or absence of plants. It concluded that when plants were added to this interior space, the participants were more productive (12% quicker reaction time) and less stressed (lower blood pressure). In addition, immediately after completing the task, participants in the room with plants present reported feeling more attentive than people in the room with no plants. Plants help people to feel more relaxed and focused, which lead to an increase in productivity, creativity, idea generation, and problem solving capabilities.
It has been suggested that hospitals which incorporate gardens improve patient well-being and lead to improvements in clinical outcomes such as reducing pain medication intake, increasing post-operation recovery rates and shortening stays (Ulrich 1983)..
A well designed and maintained Green Wall can significantly enhance a building’s appearance - whether it’s to add a new aesthetic dimension, disguise a car park, refresh a tired façade or add colour and texture to a complete wall or section
Green walls can help mitigate loss of biodiversity due to the effects of urbanization, help sustain a variety of plants, pollinators and invertebrates, and provide habitat and nesting places for various bird species. In many cases, it can also provide an alternative habitat for any wildlife displaced during construction, with the option of integrating bird houses within the structure.
Green walls offer the opportunitiy for urban agriculture, such as vertical gardens of small fruits, vegetables, and herbs.
Onsite Wastewater Treatment
Several water-recycling systems can be applied to green walls. These systems pump grey water through a green wall, which then passes through filters, gravel, and marine plants. Treated water is then sent to a grey water holding tank for household or irrigation use or released into the public water treatment system (Shirley-Smith 2006). Some of these systems also collect stormwater, which is filtered for household use or irrigation purposes.