Forced hot air main trunk replacement


Had a reputable sheet metal company come to my house to give me an estimate for replacing the main FHA trunk to a smaller height to gain some headroom in my basement. The trunk is about 40 feet long from the furnace to the end. The replacement height is 8" for the rectangular ductwork. The estimate was about $2500.00 I have no idea if this is a decent price or not. What do you think? I was a bit surprised although I really don't know about sheet metal work, so this could be good. Thanks.
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re: "The trunk is about 40 feet long from the furnace to the end."
I don't think that's enough info.
Without even discussing the location of your house (e.g. Manhattan, NY vs. Fly Creek, Ga) which could have a *huge* impact on the price, we don't know how many seams, branches, turns, etc. are involved.
Maybe $2500 for one long run with one outlet at the end is too much; maybe $2500 for a 40 foot run with 14 branches and 14 dampers for multiple zones is a great price. Hard to tell from where we're sitting.
I'm guessing that you didn't get the estimate over the phone by just asking for a quote on a "40 foot run of FHA ducting", but that's equivalent to what you're asking for here.
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You're right. Too many variables missing. Thank you for your consideration.
wrote:

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Get at least three estimates, throw out the lowest one if it's way out of line and ask lots of questions.
Pick a balance between the price and the company that makes you feel the most confident. Paying a little extra for "peace of mind" is often worth the money.
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8" is not custom work, that is the standard height for off the shelf ductwork. If you have a supply house near you, you can find prices for lengths in all the widths you need, 12", 16", 20", etc, as well as reducers and takeoffs, drive cleats, etc. You will probably need an adapter from your existing plenum to the new ductwork to start the run, they can supply that as well. See what it all comes to and determine if you want to do the job yourself.
Home Depot has some of the stuff, 8x12 and 8x16 ducts in 5 foot lengths and drive cleats, maybe a few elbows.
--
Dennis


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might consider a furnace replacement and new location to maximse energy efficency and efficent use of space
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bob haller wrote:

Might need to upgrade the furnace in any case, even if the new duct has the same cross-section in square inches. A big square duct moves air better than a wide flat one. Also often noisier. I'm not smart enough in fluidics to understand why, but that is what I was always told.
I'd certainly look Real Hard at an upgrade if 2.5 k is indeed the usual and customary price around there. When I had my furnace replaced, I had an additional trunk added out to the addition, to replace the crappy wall furnace with no a/c that was out there. IIRC, the 8x12 duct, about 30 feet, ran around $800 installed, not counting the separate bill for the concrete cutting to make it over into the crawlspace. No branches, one swept L, and split out on the end into cheap insulated flex duct. (all they will install around here for final runs, damnit.)
-- aem sends...
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Jack wrote:

Hi, If you do that, air noise level may increase. I don't know how many take-off is involved. Regardless if that is the price, I'll do it myself. Even at HD needed materials a available.
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On Thu, 01 Oct 2009 21:46:59 -0600, Tony Hwang wrote:

And I think it was about $40 for a 4' 16x8" run - and ten of those does not equal $2500...
Might be worth checking building recycler yards, too - I got 8' of (IIRC) 20x8" for $5 last year, and they've always got the registers, elbows, tees and round duct in stock for way less than HD prices.
cheers
Jules
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