I have a question about sound dampening.
We just got a new gas furnace. It replaced a 30 year old gas furnace.
The new furnace makes two fairly obnoxious noises. One is a small motor, I guess it’s a fan, that comes on about 70 seconds before the primary distribution fan comes on. It sounds a lot like a vacuum cleaner. The second noise is what I call “The dragon clearing its throat.” This noise lasts about 40 seconds and occurs in the time immediately before the main fan comes on. Once the main fan comes on, I can no longer hear this “throat clearing” noise.
I spoke with the installers. They say the noise is normal for the class of furnace (80% efficient).
My goal is to reduce this noise. It appears I have 2 choices. 1) is to go with a 90% efficient furnace, which they say is much quieter. 2) is my idea. And this idea is to decouple the furnace from the ducting. This process would replace 1 to 2 feet of rigid ducting with flexible ducting. I asked the installers for a quote on doing this work.
Other than for the noise, the new furnace is great. I don’t want to mention the brand, but it is a name brand furnace installed by a local gas furnace only company that has been around for decades.
So my question to any who will reply is: if I replace the ducting as described above, do you think it will it make any difference in the throat clearing noise?
Thanks in advance!