If you would have told me that I would be writing an article about noisy exhaust fans, I would have laughed and looked for something more interesting to write about. But at this month’s builder meeting that was hosted by Sporoco, a material supplier to the modular industry, the conversation turned to bathroom exhaust fans and how the builder’s customers were complaining about the high level of noise they generated. The fans, not the builders!
Dennis Hoffer, the guest from Sporoco, told us that he is being asked by builders and factories to find a quieter fan at a reasonable cost but so far the factories are reluctant to eat the cost increase on such a small but vital product.
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| Post this on every bathroom door |
Then I found this article from Paul Blythe, a Brit who writes about exhaust fans. Now that is a narrow profession! Here’s his take on bathroom exhaust fans.
Bathroom Fans: Fan Size, Extract Rate and Decibel Level
Bathroom Fans come in many shapes and sizes, from round to
square, and in 4″, 5″, 6″, 9″ and even 12″ versions.
They are generally white or chrome, although other colors are available. Many
people just pop down to a local store and pick up the first fan they see, but
there are a few things you should consider about bathroom fans before you buy.
What size fan do you need? For most bathrooms, a 4″
(100mm) fan is sufficient, and is indeed the standard. If you are looking to
replace an existing bathroom fan, and don’t know what size it is, don’t measure
the front! The measurement is taken from the back of the fan, and it is the
diameter of the spigot, or pipe, which protrudes from the back of the fan that
needs to be measured. If you can’t remove the fan, (you should get a qualified
electrician to do it) it is probably a 4″ one. A 6″ extractor fan is
not normally required for a bathroom. They are generally more powerful and only
required for kitchens.
In my opinion, the 2 most important things you should be
looking at are the extract rate of the fan, and the decibel level of the fan.
Obviously the best scenario is a very powerful fan with a very low decibel
level. These seem to be the 2 factors in a fan which are overlooked the most! A
lot of people seem to go just on looks, and think that all fans are basically
the same….big mistake! 4″ fans range from an extract rate of 54m3 per
hour (the minimum level required by building regulations) up to 118m3 per hour.
For a standard bathroom I’d recommend anything from around 75m3 per hour, and
if you take lots of baths or showers, creating lots of condensation, then
anything above 90m3 per hour should so the job.
But as I say, look out for the decibel level of the fan, as
a noisy fan can be particularly annoying, especially when you are having a nice
relaxing bath! As a guide, anything below 25dB is considered very quiet. 35 dB
would be classified as mid-range, and 45dB or above noisy.
Another thing that could be taken into consideration is the
amount of energy that a bathroom fan uses. These days, you can get what are
often classified as “low-watt” bathroom fans, with energy usage
levers of 5-10 watts. However, even an old fashioned bathroom fan usually uses
no more than 30w, and when you consider how short a time they are usually on
for, the cost difference in running these fans is only pence per month.
I wouldn’t focus on this is a major point to consider in
your purchase.
