Based on a previous study, it was finally concluded that the best combination of U-values for external walls and
roof are to be 0.16 and 0.34 W/m²K, respectively, together with low-e double-glazed air-filled windows (U-value =
3.1 W/m²K) with shading [10]. Malta’s climate is Mediterranean and therefore, a careful balance has to be made
when choosing materials. Extremely high insulation for walls, which may be well suited for colder climates is not
the best option for this region, as otherwise internal gains would overheat the place leading to higher consumption
for space cooling. One also has to take into consideration the thermal mass of the walls and the position of insulation
within the envelope. It would be ideal for the insulation to be placed on the outer side of external walls, thus making
the thermal mass of the wall as part of the internal environment, which helps in reducing peak temperatures.
Unfortunately, it is not possible for this project to have the insulation on the outside because the permit requires the
outer skin to be made from the local globigerina limestone, to be aesthetically in harmony with the surrounding
buildings in the village. Likewise, the use of expensive argon-filled double glazing may provide insignificant
improvements in the energy performance certificate for the hotel, when compared to standard air-filled doubleglazing.
One of the most important features for the hotel to attain high efficiency is shading for glazing elements and
this should not be under-estimated.