Connect hard duct to plenum with flex or hard ?
I've read a bunch here as I try to know what to ask for in a quote for a
AC system replacement. One concern about latest quote though.
The company wants to remove existing air handler and plenums and raise
them higher. This requires them to cut off the hard duct lines and replace
them with flex duct. They said they use an R8 duct and a 1" larger (than existing)
flex duct to connect rest of hard duct to the plenum. Also, they would have to
remove about 10 or more feet of return air hard duct as it is in the space above the
air handler to allow the raising.
I'm concerned that I'm losing (some of) the hard ducts. Should I be ?
[The company did measure and evaluate the house for Btu requirements, so they
did more than other contractors that just want to swap out the air handler and coil and leave the existing plenums...
What's the reason for raising the system up? Just for giggles?
If YOU want change, YOU have to first change.
If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!
Company replied, "more room for sloped drain pan".
Also spoke of using aircraft cable and bars to suspend unit from ceiling.
Existing one (30 yrs old) uses the metal straps attached to unit sides.
Drain pan is pretty much next to the floor.
i would want at least 3 feet of hard duct if it is gas furnace. a good sheetmetal man should make it work.
My guess is, that's just the way this company always installs their units. Possibly because they're worried about noise or vibration with the particular brand they install, or possibly because they believe it's a better quality job.
Sounds like the unit needs to be raised,flex may or may not be an issue,depends on the rest of your duct system.Increasing the size,sounds like they have calculated and correct,I'd go with it.
Last edited by dash; 02-27-2008 at 09:57 AM.
As a homeowner I recently had the same concerns. Needed to replace my 30 year old system but also had low air flow to some of my vents. Found a good hands-on contractor that took me in the attic and showed me the good (well assembled,taped,screw,insulated) and the bad (some branch lines undersized and installed with a "T" instead of "Y" connector) of my hard duct system.
He left about 3/4 of hard duct intact and used atco r8 flex to attach to new sheet metal plenum. The remaining 1/4 was replaced with atco r8 flex. With the new v-s furnace & duct re-work all my rooms get plenty of air and the system is very quiet. Listen to the guys on this site. Find you a hands-on contractor you feel you can trust and that can show and explain the answers to your problems.
short flex connectors shouldnt hurt at all, and be cheaper to install and quiet system.
never say never