Thermal Insulation Level of Sustainable Buildings, Considering, Technical Aspects and Enviromental Imapact

ESTEVES A.; MERCADO M. V.; GANEM C.

Beirut

Conferencia; Conference on Passive and Low Energy Architecture; 2005

PLEA International. Sustanaible Architecture + Urban Design

In the choice of building materials, the comprehensiveness of insulation and the standards of construction will each influence the ability of a building to retain heat. The opaque elements of a building´s envelope - walls and roof - play a role in effective passive solar design. Of key importance is the level of thermal insulation a building affords. A well insulated building will retain heat from the sun and from internal sources such as kitchens, lighting, machinery and the occupants themselves, as well as from the heating system, so reducing the need to provide further artificial heat. In summer, thermal insulation acts avoiding heat gain through the opaque envelope. All thermal insulation materials have embodied energy. For example, If we select polystyrene or polyurethane 110 MJ/kg or 182 MJ/kg of energy is used to make them respectively. This is an embodied energy, that we call initial energetic cost. The operative energetic cost is energy transmitted by materials in the wall or roof during the life-cycle of a building. Initial and operative energetic cost are a interesting tool to design sustainable buildings.