Building Envelope – The physical separator between the internal environment of a building and the external environment, including resistance to air, water, heat, light, and noise transfer.
Façade – Typically the vertical element of a building envelope, between the Floor and Roof, which provides resistance to air, water, heat, light, and noise transfer. The façade will typically encompass Wall and Glazing. (Façades may also be non-vertical/angled).
Façade Performance – A benchmark overall performance value for the façade alone, constituting opaque wall and glazed elements and excluding the roof and the floor. This provides the option to improve the Overall Thermal Performance of the façade as Selected Façade Performance.
Floor – The element on the lowermost part of a building envelope, which provides resistance to air, water, heat, light, and noise transfer.
Glazing – The transparent/translucent components of the façade. This denotes the framing and structure that supports these components.
Overall Heat Loss Method – Maximum acceptable level of transmission heat loss through the building envelope in terms of the maximum average U-Value of all elements contributing to heat loss.
Overall Performance – A benchmark overall thermal performance value for the envelope of the entire building to include walls, glazing, floor, and roof.
Roof – The element on the uppermost part of a building envelope, which provides resistance to air, water, heat, light, and noise transfer.
R-value – Measurement of thermal resistance, which relates to a building element and is a measure of the resistance to heat passing through that element when unit temperature difference is maintained between the ambient air temperatures on each side. It is expressed in m2K/W or ft2 °F hr/ BTU.
Thermal Performance – The measurement of energy transfer through the building envelope, between the internal environment of a building and the external environment.
U-value – Measurement of thermal transmittance, which relates to a building element and is a measure of the rate at which heat passes through that element when unit temperature difference is maintained between the ambient air temperatures on each side. It is expressed in W/m2K or BTU/ft2 °F hr.
Wall – The opaque components of the façade.
