Hi guys. I hope this isn't an often-asked question. I browsed through the first 5 pages of the HVAC forum and didn't see it.
We purchased a home last spring (built in 97), and it has furnace/forced air ducts. The ducts in question are in the unfinished basement, mostly on one side of the house (furthest from the furnace). Whenever the furnace is on, the ducts make noises (pinging, clanging, sometimes quiet, sometimes pretty loud).
So the first question is, what is causing this? Is it simply metal expansion from the heat?
Second, is there a way to quiet this down? The ducts that are making most of the noise are directly under the master bedroom, of course.