Forced hot air main trunk replacement

Posted by bob haller on October 1, 2009, 7:31 pm

...

> >Had a reputable sheet metal company come to my house to give me an estim=

ate

> >for replacing the main FHA trunk to a smaller height to gain some headro=

> >in my basement. =EF=BF=BDThe trunk is about 40 feet long from the furnac=

e to the

> >end. =EF=BF=BDThe replacement height is 8" for the rectangular ductwork.=

=EF=BF=BDThe

> >estimate was about $2500.00 =EF=BF=BDI have no idea if this is a decent =

price or

> >not. =EF=BF=BDWhat do you think? =EF=BF=BDI was a bit surprised although=

I really don't know

> >about sheet metal work, so this could be good. =EF=BF=BDThanks.

> 8" is not custom work, that is the standard height for off the shelf duct=

work.

> If you have a supply house near you, you can find prices for lengths in a=

> 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 p=

lenum

> to the new ductwork to start the run, they can supply that as well. See w=

hat

> 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 a=

> drive cleats, maybe a few elbows.
> --
> Dennis

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

Posted by aemeijers on October 1, 2009, 8:18 pm

bob haller wrote:

>>> 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.

>> 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

>
> might consider a furnace replacement and new location to maximse
> energy efficency and efficent use of space

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...

Posted by Tony Hwang on October 1, 2009, 11:46 pm

Jack wrote:

> 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.
>
>

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.

Posted by Jules on October 2, 2009, 9:44 am

On Thu, 01 Oct 2009 21:46:59 -0600, Tony Hwang wrote:

> Even at HD needed materials a available.

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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Forced hot air main trunk replacement - Page 2