Author Topic: Expand furnace intake?  (Read 1222 times)


  • Bristles
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  • Age: 37
  • Location: The best state in the Union (MT)
Expand furnace intake?
« on: December 06, 2013, 04:24:14 PM »
I had a new Lennox 93% efficient furnace installed last March.  About 2 weeks agao we got an odd squeak from furnace which we heard through vents and confirmed origin when I checked on the furnace in the attic.  We called out the installer and he had a look.  He placed some vibration absorbers in a couple places that had settled since install and oiled a couple spots .  The squeak is gone but he also claimed that the squeak was becasue the intake for furnace was inadequate, this caused the motor to run more and would drop efficiency and cause wear in the long run.  I have 2 intakes in the house  (1 in basement another of same size upstairs) and the holes could be cut larger to match the duct size.

Before I start carving walls though I need to know if what he said made any sense.

And while I'm asking - I'm trying to in-source more of my work but I have no background in this or any other home maintenance area.  Can you recommend some good books, youtube videos, etc to get started with?



  • Handlebar Stache
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Re: Expand furnace intake?
« Reply #1 on: December 06, 2013, 05:08:11 PM »
Can't give you a specific answer, but I can attest that it is a real problem.

A few years ago I built a custom home for an older, extremely difficult client. He insisted that I bid the project without plumbing or HVAC, since his good ole buddy was the greatest plumber/HVAC guy on the planet.  Didn't take long to figure out that this outfit (that we nicknamed "dummy and daddy") didn't have the smarts to build an outhouse, or put a window AC in.

Long story, but the bottom line is that they grossly undersized the returns and  the furnace self destructed before the warranty expired. the factory service guy shows up, says it's a wonder it ever worked in the first place, and that they would only honor the warranty IF my customer hired a professional to re-do the ductwork. $4500 later, my client got a fully functional heating system.

A competent service company should have the equipment and knowledge to determine exactly how much of a return air deficit you are dealing with, and if it can be addressed without too much rework. Good luck.