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Recommend a very quiet, low-CFM exhaust fan?

davidmeiland | Posted in Mechanicals on

I need the quietest, continuous-run bath fan available for a small building. It’s a 400-square-foot, 4500-cubic-foot space to be used as a painting studio and occasional guest quarters. One bath, no kitchen. I’m expecting it to be 1-2 ACH50.

The plan is to install the fan in the bathroom ceiling, although there is a very small concealed space that could house an inline fan. I don’t think this project needs a HRV, and in any case there isn’t anywhere to install the ductwork for one.

I usually use 80 CFM Whispergreen fans in my projects, and they work fine, although I don’t really think they “whisper”. The 50 CFM Whispergreen model does not have the variable speed feature. My goal is to install something that can run at a low CFM rate most of the time, and ramp up if someone uses the shower. Most of all, it needs to be quiet.

Any recommendations?

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  1. GBA Editor
    Martin Holladay | | #1

    I would choose one of the Panasonic fans. If the airflow rate of the fan is too much for your small space, you can control the fan with a timer that runs for only 20 minutes every hour (or any other portion of an hour that you care to program).

  2. davidmeiland | | #2

    Anyone aware of an inline fan that's either low CFM or variable speed? I have used the Panasonic inline fans a couple of times, but the smallest one is 110CFM and you can't dial it back. I have enough room to install an inline fan with either 1 or 2 inlets (could vent the main space as well as the bathroom) but want to be able to run

  3. user-659915 | | #3

    If it's a painting studio, what kind of painting? Build-up of toxic solvents may be more of a concern than the usual humidity issues. Oils will need more ventilation than acrylics or watercolors, encaustics are worse still.

  4. davidmeiland | | #4

    James, the owner does small watercolors, otherwise I would be asking the how-do-I-provide-makeup-air-for-a-1200CFM-Wolf-hood question.

  5. user-1105327 | | #5

    i like the panasonic fans, too. but even a low-sone bath fan can sound like a sikorksky if the ducting is inadequate. a short section of flexible duct between the fan and the negative-sloping rigid duct seems to help.

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