Impact of ductwork leakage on the fan energy use and sound production of central mechanical ventilation units in houses

Various studies demonstrate a significant impact of ductwork leakage on the fan power consumption of ventilation systems. They have shown that the total energy used by fans can be reduced by 30-50% by improving the airtightness of the ductwork system. However, most of those studies focused on non-residential and multi-family buildings. This study focuses on single-family dwellings; specifically houses.  
This paper first explains why fan energy use increases with ductwork leakage and then presents a model, which is based upon (Leprince & Carrié, 2018), that is used to estimate the impact of ductwork leakage on the fan energy use of central mechanical ventilation units with heat recovery in three houses and with a DCV system in one house. The calculations have shown that fans connected to leaky ductwork (3*Class A) in the four houses use 57-169% more energy than fans connected to very airtight ductwork (Class D), if they ventilate to provide the hygienic flowrate at Air Terminal Devices.  
Obviously, the harder a mechanical ventilation unit has to work to displace more air to achieve the hygienic flowrate at the Air Terminal Devices, the more sound it will produce. It is estimated that a mechanical ventilation unit with heat recovery will produce at least 2.5 dB(A) more sound pressure level in the habitable rooms whith leaky ductwork.