Per my experiments in sound-reduction... it was a failure. My plan was to replace the centrifugal blower with an array of axial fans. Unfortunately, the axial fans were not able to tolerate the static pressure induced by the heat exchanger and airflow path in the Merrimack. So, the prototype was quieter, but the airflow was significantly reduced. I am abandoning that aspect of the project. I may look into more acoustic shielding / dampening material as the last resort, but I don't expect miracles. Sorry guys, I would have loved to come up with a kit that could have been a simple retrofit that was significantly quieter. We will just have to wait and see if Vermont Castings ever comes out with a quieter blower.