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UK diy (uk.d-i-y) For the discussion of all topics related to diy (do-it-yourself) in the UK. All levels of experience and proficency are welcome to join in to ask questions or offer solutions. |
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Wiki: Fan noise reduction
Another one to check out before it goes live...
'''Fan noise''' can be a persistant minor irritant. The good news is that [[:Category:Noise|noise reduction]] is fairly simple to install, and can reduce noise levels massively. ===Buying quiet=== Extractor fans cover the noise level range from under 40dB to over 50dB. Choosing a low noise fan at purchase time can reduce noise by upto 10dB. ===Flexible mounting=== Fans can be mounted on rubber washers (or other flexible mounts) to prevent transmission of vibration to the wall or joist. To be effective, screws should be done up until there is no slack movement, but no further. Overtightening would eliminate the flexibility of the mounting. ___ |_ _| --- screw head === === --- penny washer === === --- tap washer ====== ====== --- fan case === === --- tap washer ////// ////// --- wall ////// ////// Simple but effective flexible mounting For large fans mounted by threaded steel rod, the rod can sit in a wider hole lined with soft plastic pipe, with rubber washers top and bottom to allow a tiny bit of movement. __||__ --- threaded rod protruding | | --- locking nut |______| | | --- locking nut |______| ____________ --- penny washer ____________ ______|__ __|______ --- rubber tap washer | | | | | | | | | | |----- threaded rod | | | | | | | |--- soft plastic pipe | | | | Joist | | | | Joist | | | | _________| | | |___________ |____________| --- tap washer ____________ --- penny washer | | |______| --- locking nut || || --- threaded rod || Various sizes of soft (rubbery) plastic pipe can be had from car accessory dealers etc. ===Damping=== Attaching damping material to the fan case interior can [[:Category:Noise|reduce noise]] to some degree. Of course the damping material should not get close to the fan blades, nor block [[Motor repair|motor]] cooling airflow. A fireproof or self extinguishing material is to be recommended, as fans do catch fire at times. The amount of [[:Category:Noise|noise reduction]] this provides is limited, but its very simple to do, and nothing is visible when the work is finished. ===Speed control=== Reducing fan speed at times when full extraction isn't needed reduces noise a fair bit. It does also heavily reduce flow rate, but in some cases this is acceptable. Permanent speed reduction can achieve quite a bit of [[:Category:Noise| noise reduction]] with some fans. This is most simply done with a [[Droppers|dropper]] or transformer for small amounts of reduction, or an electronic controller for larger amounts. In the few cases where motor noise is a large component of total noise, reducing speed is not very effective. However these fans are in the minority. ===Remote mounting (eg attic)=== Remote mounting of fans reduces noise transmission to the house interior. This is often done with bathroom extractor fans, an inline fan is mounted in the loft. ===Bigger fan=== A bigger fan running slower produces less noise when all other things are equal. Naturally all other things are rarely equal, but looking at fans a size up run at reduced speed can often get you a lower noise figure. The downside is that purchase price goes up rapidly as fan size increases. ===Balancing & levelling blades=== With ceiling fans, balancing and levelling the blades can make quite a difference. This sometimes helps with other types of fan if the metal blades have become bent out of alignment - though some seem to work quite happily with blades pointing all over the place. Blade alignment and balance primarily addresses shaking, thumping, flapping and other low frequency noises. It does also have some effect on the high frequency air movement noise, but not as much. ===Duct choice=== Corrugated flexible ducting has considerable resistance to airflow, necessitating the use of a more powerful fan to get sufficient flow. Rigid duct enables use of a quieter fan. ===[[Baffle box]]=== A well baffled air path can produce major [[:Category:Noise|noise reduction]]. This measure can produce much more result than the others, and is used for serious noise problems. It can be used not only to reduce fan & motor noise, but also to filter out almost all the noise from outdoors when moving air in or out. When installing a remote fan in the attic, this effect can be incorporated to a limited but still useful extent simply by snaking the air tube. This is not nearly as effective as a proper [[baffle box]], but its relatively easy to do. ===Single baffle=== The diminutive form of the baffle box is an empty box lined with [[carpet]] (or other material) with an outlet hole at 90 degrees to the inlet. These give modest noise reduction, but are very easy and quick to construct. Small boxes for computer fans can even be made from [[Damping material|triplewall cardboard]]. These are mainly used to quieten portable appliances such as computers, projectors, lab equipment etc. ==See Also== * [[:Category:Noise]] * [[Special:Allpages|Wiki Contents]] * [[Special:Categories|Wiki Subject Categories]] [[Category:Noise]] [[Category:Cooling]] [[Category:Bathrooms]] [[Category:Kitchens]] NT |
#2
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Fan noise reduction
wrote in message ... Another one to check out before it goes live... '''Fan noise''' can be a persistant minor irritant. The good news is that [[:Category:Noise|noise reduction]] is fairly simple to install, and can reduce noise levels massively. snipped Or better still get this firm to manufacture a 240Volt model external fan for the British market. See, http://www.continentalfan.com/ext.htm Don |
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