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Mechanical ventilation noise
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I am contemplating installing mechanical ventilation in a brick and block build. Will we get an annoying background hum? We are building brick and block specifically cos we want a really quiet house. Any experiences?
If installed incorrect then yes you can, depending on th flow rate you may get some noise from the moving air at the inlet and outlets in your rooms but a good system install should be balanced so its very low. A poor install of the plant could give a hum if its not mechanically damped at the fixing to the structure.
The best bet is to get a professional HVAC engineer to design and size the system and its duct work, then you have a spec to issue to various installers.
Noise in these systems is often a case of the unit working too hard - and as a result, your engineer will need to supply a system that is plenty big enough for the house you are building. I've recently been to a huge self-build in the Cotswolds where the house was so big they installed two units. The MVHR was on, but you couldn't hear it.
Thanks folks, very helpful.
My experience is that a system from an HVAC engineer will be overdimensioned and therefore noisy (and expensive). I use CVC direct who supply inexpensive self contained kits ideal for the self builder and...totally silent.
Installer of Ventilation, heat recovery and vacuum systems
There are three possible causes for noise from a MVHR unit,
1, the motor/s being of poor quality
2, the motor/s running at too high revs
3, poor installation
quality of the motors is (generally) reflected in the MVHR units cost
excessive motor speed is caused by the unit being under-sized for the property
Have the system sized properly according to CIBSE / RIBA recommendations, Building Regs on number of air changes per hour.
Find a unit with a low noise figure.
Have appropriate controls package fitted (humidistats/summer override etc.
Have the Air Handling Unit (AHU)/ MVHR unit and ducting installed correctly i.e. mechanically isolated from the building structure with Tico pads or the like to reduce conductive noise transmission. Install the ducting as straight as possible to ensure flow is as laminar as possible.
Fit damping in structure adjacent to air handling unit.
Fit silencers and turbinates where necessary.
Lag the ducting with a foam insulation such as armacell ZH sheet.
Follow manufacturer's recommendations about thermal and acoustic insulation of air handling unit. Ieally you should find an AHU with integral acoustic and thermal insulation to avoid problems with warranty fire ratings, reduced
Follow maintenance recommendations on the UHU / MVHRU, filters and vents.
As per post #1
"The best bet is to get a professional HVAC engineer to design and size the system and its duct work, then you have a spec to issue to various installers".
You also have some come back if the system doesn't perform to spec, not to mention the time you will save researching methods, materials and suppliers .
Centaur Special Interest Media, Ascent Publishing Ltd, 2 Sugar Brook Court, Aston Road, Bromsgrove, Worcestershire, B60 3EX. Tel: 01527 834435