Green Wall : energy savings

Greener Cities

The greening of buildings, in particular living walls on exterior surfaces, helps create more sustainable cities.

MORE GREEN

An external green wall generates energy savings and reduces CO² emissions.

URBAN HEAT ISLANDS

Plants in fact lessen what are known as "urban heat islands".

An urban heat island is a metropolitan area that is significantly warmer than its surrounding rural area. This leads to the creation of urban microclimates: the closer you get to the city centre, the higher the temperature. As the name suggests, urban heat islands are due to increasing urbanization, high quantities of hard surfaces and materials used such as concrete and asphalt which absorb heat during the day and later release it, thereby increasing the heat island effect.

WHAT A VERTICAL GARDEN OFFERS

Water and plants represent two ways of cooling the air in the daytime. Green walls can therefore play a very significant heat regulating role, firstly due to the shade they provide and above all due to evapotranspiration which cools the surrounding air, and the formation of dew which has a buffer effect. This approach may be accompanied by well-founded sustainable development policies, for example creating irrigation systems for green walls by collecting and filtering rainwater.

Highly urbanized areas have over time destroyed the biodiversity of our lands. Green walls and the large variety of plants growing on them become real ecosystems providing habitats for small life forms such as birds, butterflies, bees and ladybirds.

THERMAL AND ACOUSTIC COMFORT

Outdoor vertical gardens have considerable potential in terms of resolving energy- and environment-related issues connected with buildings.

THERMAL BENEFITS AND ENERGY SAVINGS

The modular green wall system Vertiss is especially efficient in terms of enhancing thermal insulation of buildings due to its geometric and structural features. The Vertiss® modular greening system consists of several layers which achieve various beneficial interacting effects. These effects reduce heat flows through the façade of the buildings.

HOW DOES IT WORKS ?

The plant cover helps generate energy savings in buildings due to the combined effects of evapotranspiration, shading and reflection of sunlight.

The substrate layer is approximately 13 cm thick and helps disperse water vapour away from the building envelope.

The EPP layer (expanded polypropylene) of the Vertiss module has a thermal conductivity of 0.04 W/m.K. It represents an additional insulating and shading layer.

The 4 cm airgap between the building façade and the back of the Vertiss module evacuates by convection heat flows through the wall cladding in the upper part.

The Vertiss modular system reduces the amplitude of this heat flow through the building envelope and helps to prevent extremes of temperature over the building's planted surface.

In summertime, it reduces the inside wall temperature by an average of 1.5°C, both in daytime and at night. The reduction in heat flows produced by Vertiss vertical gardens results in lower air conditioning costs in summer or in hot countries.

The reduced thermal load is also effective in winter but the benefits in terms of heating costs are not as great as for air conditioning. Air conditioning requirements are on average reduced by about 71 % whereas for heating requirements the figure is approximately 4 %.

GREEN WALLS AND NOISE REDUCTION

It's very common to develop a headache in a room full of people. Phones ringing, exclamations, conversations, music etc. ... all these noises resonate and bounce off walls and ceilings.

Office noise levels are between 0 and 70 decibels. The consequences are significant: loss of productivity, physical discomfort, headaches, migraines, increased fatigue and concentration problems. Living walls offer acoustic benefits by absorbing all these sounds and therefore offering improved sound protection.

Plants reduce and absorb noise. Yet the level of noise reduction is proportional and depends on the number of plants and the level of noise in the room. In all cases the acoustics of a room are improved.

Green walls insulate against noise and vibration and reduce sound penetration. They also help to absorb echo in buildings and reduce noise pollution in our modern cities.