Fan Noise Issue Resolved

For nearly a year, we have been searching for a solution to a noise being produced by a boiler fan that heats our kilns. You can read our initial post about the noise here. We finally have some good news to share. This spring, we located an engineering firm in the U.K. that specializes in designing fan modifications to reduce tonal fan noise, which was the problem we were experiencing. The engineering firm designed a custom solution for our fan, which we have implemented to reduce the offending tone. After more than a week of testing this modification, we are confident we have found the solution. 

Again, we apologize to our neighbors for the noise disruption and thank you for your patience as we worked to fix this. 

New Fan Update

Since the new fan was installed, we have been measuring sound levels from the property line and at a neighboring home. When we ordered the fan, we were told the new fan would have a blade passage tone of 23 dB lower than the previous fan. It’s measuring just 7 dB lower. Obviously, this is another major disappointment.

We have since been in contact with the Director of Engineering at Twin City Fans (the fan manufacturer), as well as the fan rep, who has visited the mill and performed some additional testing. 

At this point, we’re working on several additional solutions:

1. Reducing the wheel size in the fan housing: The fan manufacturer has evidence from another project showing that by doing this, it could reduce the sound level of the tone by up to 10dB. This would be an improvement, but it may not completely solve the problem.

2. Replacing the silencers. We are now working with four additional engineering and manufacturing firms regarding better-suited silencer designs. We are in the process of receiving conceptual designs and proposals from them and hope to have a final decision in the next few weeks.

Unfortunately, there is no simple solution to this problem. We will continue to keep the fan in pilot mode in the evenings and on weekends and run at a reduced level during the day until this issue is solved. 

New Fan Testing

The new fan has been installed, along with the larger smokestack. We are currently monitoring noise levels while we operate the fan at various speeds and make adjustments to the equipment. We would appreciate any reports of noise be directed to with your general location. We will have more information in the next few weeks. Again, we appreciate the patience of the community as we work to solve this problem.


The cement has been poured and pipes have been designed for the new fan. We’re ready for the install once the fan arrives. We have not received any updates from the manufacturer; however, when the order was placed in mid-January, we were told to expect a minimum of 12 weeks for manufacturing and delivery. We are still operating on that timeline unless we hear otherwise. 

We continue to operate the fan at a lower (quieter) RPM and in pilot-light mode in the evenings and on weekends. 

A New Fan and Stack

After consulting with three different manufacturers, we’ve ordered a new custom fan that is being designed to produce significantly lower sound levels. This larger fan contains 20 blades (vs 8 blades on the current fan), runs at a slower RPM (1700 vs 2200), and its blades are specifically designed to reduce noise (backward curved vs radial blade). Along with the fan, we’ve ordered a new stack and all new pipes. We’re expecting the design and delivery to take 12 weeks, at a minimum. We will post updates as we receive them from the manufacturer.

We have been running slightly above pilot-light mode during the day and in complete pilot mode in the evenings since December 21. We will continue to operate at these levels until the new equipment is installed. As always, please feel free to email us at with questions or concerns. Thank you.

New Muffler Update

After working with engineers and having a second muffler custom designed and expedited, we are sorry to report the second muffler has failed to solve the issue. This obviously is not the situation we were hoping for. We apologize to the members of the community who have been affected by the noise for the past four months. Please understand that we want this resolved as quickly as possible, as well. Our company has been a part of this community since 1949. We are committed to being a good neighbor. We wish there was a quick and easy fix to the noise.

We have located a manufacturer who is willing to design an alternate fan, which we are told will produce much lower sound levels. A new fan will most likely result in the need for a larger smokestack. We are waiting to hear how long this will take. We have asked that the fan be expedited at our expense.

Again, we apologize for the disturbances our operations have caused. We will continue operating the fan in pilot-light mode in the evenings until a solution is determined. We will operate in pilot-light mode completely on Dec. 24-25 with the hopes that everyone can have a peaceful holiday.

New Sound Muffler Shipped

We received confirmation that the new muffler shipped on Friday. We were not given an estimated delivery date, but we are assuming it will arrive within 7 business days (based on the schedule of the previous muffler). Please keep in mind that the muffler is traveling from Canada and has to go through customs. We will keep everyone posted on the schedule as soon as we know more. The plan is to have it installed within 24 hours of its delivery date.

New Sound Muffler Ordered

A second sound muffler has been ordered. The new muffler will work in conjunction with the current muffler to further reduce the sound level generated by the boiler’s exhaust fan. This muffler is specifically designed to reduce only the sound level of the fan’s tone (about 315 Hz), whereas the current muffler has shown to be more effective at reducing non-tonal sounds. We are working with the manufacturer’s engineers and our sound consultant on the project. We are having it expedited, so instead of the typical 8-10 week design and delivery time frame, it will be delivered in about four weeks. We understand this isn’t ideal; however, it’s the quickest they can have it to us. We will continue to operate in pilot-light mode in the evenings and on weekends until the second muffler is installed. We also will continue to share progress on this site.