With respect to the energy savings for heating, due to the increase
of the insulating properties with greening systems, the
additional thermal resistance is assumed to be 0.09 km2 W1. This
value is used for both the direct and indirect greening systems
analysed due to the fact that there is a stagnant air layer in and
behind the foliage [13]. For the living wall systems the thermal
transmittance of the substrate and the materials used are added.
Concerning the different vertical greening systems the energy cost
savings for heating are represented in Table 6. Software Termo
allowed the simulation of different situations (non green and options
1e2Ae2Be3Ae3Be4) through the increase of thermal
properties of the south façade (see Fig. 2) and considering the
different thermal transmittance of the greening systems analysed;
the economic benefit for heating calculated go from 7.02 up to 19.17
V/year. The calculation of the economic effects (cash spare) due to
the energy reduction resulting from the installation of the analysed
vertical greening systems, was done making reference to the gas
and energy bills (from the past two years) of an office building. This
building is located in Genoa, as well as the building used for this
analysis, and has similar characteristics. To exactly relate this
building to the virtual building used for this CBA, a model with the
software Termo (Microsoftware) was realized for both buildings. To
obtain the costs (and savings) for air condition and heating for the
simulation building, a calculation of the energy and gas consumption
for both buildings was made; enabling to obtain an economic
benefit related to the energy saving due to the green layer.