One of the main difficulties in designing low energy buildings can be the prevention of noise break-in via vented facades. This chapter looks at a range of options and details which can be used to reduce environmental noise break-in from the many noisy sources affecting modern buildings, including motorways, dual carriageways, trains, aeroplanes and inner city noise.

To overcome this issue, an attenuator is selected and incorporated into the facade. This attenuator is typically combined with a damper such to control the flow of air into the building, with a weather louvre being used externally to provide the weather protection. MACH Acoustics describes this combination of units as the ‘NAT Vent Box’. The outline schematic of this system is shown below. The damper can take the form of a thermal volume control damper, open-able vents within the facade, thermal insulated doors etc.