by Cosmo » Sun Feb 24, 2019 2:07 pm
I have limited experience. The ducting is 1M in length. I cut about 6 inches off of it to fit correctly. Was a big improvement for me and well worth the cost. There is the sound from the combustion chamber, fans, air movement etc.
In my case ducting does quiet the sound from the ducting in a measurable and pleasing way. You can see in the video how much louder my voice is (80DB ompared to the background noise. In my case at 60 DB the heater is about 5DB louder than silence which is pretty good.
Where and how you have the heating unit installed has a lot to do with the other sounds. I can probably dampen that sound too if you take that into consideration in the design. Besides lowering the decibels the ducting seemed to lower the pitch of the sound that does escape the hot air vent. To me - before it had a higher pitch fan whine now it sounds to me like a lower pitch sound at lower volume, which is more agreeable to me.
Adding some of the acoustical ducting to the air intake of the furnace helps lower the sound too.
Others have this unit and may want to share their experience.
=Cosmo