I’ve been involved in contracting for about 15 years. Most of my experience is primarily in that carpentry side of things. Recently, I hired an HVAC contractor to install a central air system in my own home. The install went really well and everything seems to look and work fine, but, the first floor vents (not the intakes) are a little noisey. The second floor ductwork is insulated, the first floor ductwork, which is in the basement is not insulated. If I insulated the basement ductwork, would this cut down on the noise??? Thanks.
Discussion Forum
Discussion Forum
Up Next
Video Shorts
Featured Story
You don't have to sacrifice historical elements of a house in the name of energy efficiency.
Featured Video
Highlights
"I have learned so much thanks to the searchable articles on the FHB website. I can confidently say that I expect to be a life-long subscriber." - M.K.
Replies
There several types of noise in HVAC systems. One is the noise of air being forced through a restriction (like a duct or a register), one is the mecahnical noise made by blowers, compressors and the like.
External duct wrap does a little to attenuate noise, but very little. Duct liner will quite down a system, but that's not really an option here.
To get our terms straight, by "vents", I assume you mean supply registers/grilles. Grilles that warm or cool air comes out of to the room. Intakes would be return grilles taking air back to the unit.
If the basement is unconditioned, then seal and insulate the ducts. If it is conditioned, its optional. It won't solve the noise problem.
If the noise you hear is caused by friction through the registers, you can do several things to reduce the noise. 1- use larger registers, if you do not want to decrease the flow, 2- open the register more and use a volume damper at the "branch" to slow down the flow. There will be friction noise at the damper, away from the register and earshot. If there are no volume dampers at branches, have the contractor come out and finish the job because it is an incomplete installation. Or install them yourself if you'd rather.
Other causes of noise, like vibrations and mechanical noise being transmitted though the ductwork are more difficult to diagnose and solve.
If what you hear is the compressor noise conducted thru the ducts, a simple muffler is to open a duct and install bundles of 9" or longer lightweight (thinnest wall you can get) PVC pipe bundeled glued togehter. If turbulence at the register, heed the previous advice.