The building fabric is an essential component of any house, because it plays a major role in regulating the flow of energy in and out of the building.
Optimal design of the building fabric can provide significant reductions in heating and cooling loads which in turn reduces demand on mechanical equipment and the energy the required to drive it. The cost of efficient external materials is offset by the savings in reduced energy consumption and also reduces the negative impact on our living environment. External materials are considered for their fitness of purpose and life cycle cost. In modern design window walls have become a recurring feature so it is important to design highly efficient glazing systems that provide low emittance values (U) and higher solar heat gain factors (SHGC) and so contributing significantly to the thermal efficiency of the house. Unconditioned utlity rooms can be isolated with insulation to internal and external walls to reduce their impact on the entire building.
When choosing structural systems and external claddings it is also important to allow adequate space in voids and cavities for thermal insulation and air gaps. The thermal efficiency of any product or material usually requires a minimum air gap to optimise its R value (R-value is a measure of resistance to heat flow through a given thickness of material). The choice of the approprate thermal insulation will depend on the design of the bulding in relation to element of the building fabric, and also the inherint values of the material itself. The building fabric in conjunction with other elements such as solar orientation, summer shading, air movement, etc, contributes to the holistic energy performance of the entire building.