Facades and Summer Performance of Buildings - Low Energy Cooling for Sustainable Buildings - page 21

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Fa¸ades and Summer
Performance of Buildings
Low-energy buildings in European and other moderate climates should have the
following features:
excellent thermal separation and low transmission losses between the inside and
outside through a highly insulated building skin;
high-quality glazing with U -values below at least 1.5Wm − 2 K − 1 and a reasonably
high total energy transmittance with a g -value above 60%;
heat recovery of ventilation air in winter for very high energy efficiency standards
(passive building).
These features are all necessary to provide thermal comfort in winter at a low
primary energy consumption. A good summer performance of sustainable buildings,
especially offices and commercial buildings, depends on additional features:
excellent sun protection through shading devices, if possible on the outside of the
fa¸ade;
night ventilation schemes to remove at least a part of the daily loads;
earth heat exchangers to precool ventilation air or to directly cool part of the building
mass.