Noise Characteristics of AirMaster Heat Recovery Units
Noise Emissions from Heat Recovery Ventilation
At full 100% throughput, AirMaster heat recovery ventilation units emit only 35 dB(A) at 1m. Where noise limitation is crucial, a further reduction can be obtained by setting air flow to 80% of full throughput, resulting in only 30 dB(A) at 1m.
EC (electronic commutation) drive motors enable the air handling unit fans to modulate between 40% and 100% of full throughput. This means that air delivery is always closely aligned to room requirements, so that the power consumption profile is consistently as low as possible. It is not necessary to have defined speed settings, such as trickle or boost.
AirMaster heat recovery ventilation units placed against the walls of a room to be served have negligible air pressure loss. Units can also be used away from walls, with ducting of up to around 10m length. In these cases, the fan drive motor is delivered with a higher setting, so that the fan can overcome duct pressure loss and still manage the required air volume. Although noise emission for these units is higher, the duct muffling effect largely neutralises this increase and holds emitted noise to the same duct-free 30 and 35 dB(A) levels.
AirMaster air handling units with only 30 dB(A) noise emission are a valuable resource for designers tasked with finding ventilation solutions for projects such as Special Educational Needs (SEN) schools, clinics and community centres with quiet areas.
External noise reduction on passing through AirMaster Air Handling units
Even with the bypass damper fully open, AirMaster heat recovery ventilation units are able to reduce noise by approximately 49 dB. When placed next to classroom windows exposed to traffic noise around 60 dB(A), the muffling effect of direct ventilation units reduces the resultant noise ingress to 7 dB(A). This is so low as to be negligible.
Where the level of environmental noise is known (typically from a field survey), SAV Systems can provide a spreadsheet to establish the net impact of such noise after passing through an AirMaster unit. This would be relevant for situations such as classrooms subject to traffic noise.
Having installed an AirMaster air handling unit for its low noise characteristic, any site operator can rest assured that equipment noise will not increase during its operating lifetime. With maximum throughput, it does what it says on the tin: 35 dB(A) @ 1m.