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cost to redo ductwork...wow!

Posted by linday12 (My Page) on
Sun, Aug 7, 11 at 16:55

I had the third repairman out to see why my ac isn't cooling (it got to 82 inside recently). He said that it is working as well as can be expected after doing all the measuring of temps coming in and going out, etc. He recommended that the duct work in the attic be completely replaced for better efficiency. He seemed very capable and had us try some easier fixes first such as sealing the attic door better and blowing out the insulation that was obstructing the attic vents. None of that helped. His quote though was vague...somewhere between $3-4,000. That seems rather high and I don't like the broad range. Any advice please??? Oh, we live in Houston and it IS really hot here!


Follow-Up Postings:

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RE: cost to redo ductwork...wow!

The cost is going to depend on the amount of ducting you have. Also, much of the cost is the difficulty factor. Have you been in your attic? I advise you go up there and think about how difficult it will be to be up there all day and not have a heat stroke! All in all, the number does not suprise me. Although, they should be able to give you an exact number. Make sure whoever does it is sealing the ducting and doing a duct blaster test.

Here is a link that might be useful: Heating, A/C and Energy Bloggart


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RE: cost to redo ductwork...wow!

having done this type of work myself..it isn't so out of line.
hvac companies charge approx $250 to $300 per duct run
in my area.
and yes it is HOT work.in an existing home it is hot dirty work.
I'd ask to see some pics of his work, question as to methods of sealing ductwork (mastic seals should be used)
type of ductwork he is replacing with..change in duct sizes
and duct layout for better air flow. then things like if the duct is flex will it be strapped off attic floor

is replacing duct really necessary..or would mastic sealing ductwork, supply boxes, plenums and strapping existing ducts suffice?

I test ductwork on a regular basis and find that 30% leakage on new construction isn't unusual..higher in existing homes sometimes. your mechanicals may be working all right, but if the air you are conditioning isn't making it into the living space..then your house is hot.

often things like improving duct lekage and air barrier from attic to living space will help performnace of hvac.
things like recessed lights are huge, hot attic air entering the house each time hvac system comes on..year round.

one option would to get an unbiased energy audit.
have house tested for air leakage and ducts for air leakage. make sure you feel where the leaks are and know what needs to be sealed.

best of luck.


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RE: cost to redo ductwork...wow!

I did it myself but mine was all in the basement and in the walls and it wasn't difficult but it sure was time consuming to fix the issues left from the installer and sealing things up like they should be. I was quoted over 3k on mine and he would have earned his money.


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RE: cost to redo ductwork...wow!

How can any energy audit be unbiased unless you do it yourself? All the companies that do these audits give you estimates for work they would do to improve energy efficiency. So they're not unbiased. They want your money.

Living in AZ in a house that was built in 1998 during the "boom", there are tons of code violations, but since I was not the original owner, I have no recourse.

I can't say for sure, but it appears that one of the violations involves roofing -- the tile -- and/or the attic "floor". The insulation is filthy and some is brown (mold?), the ductwork has huge piles of dust sitting on top of it, tape on the air handler is coming off, there is a piece of duct tape holding up a beam of some sort, and a couple of holes I saw in the attic (all I did was pop my head in) drilled in the plywood "floor" for electrical wires are splintered and cracked. I don't know where all that excess wood is going.

One of the great big flexible ducts has a plastic tie around it almost choking it off. In much of the attic, there is so much pink stuff I can't see where the ducts are or where I might walk. In another part of the attic, the insulation is completely missing and the ceiling has cracked below.

I saw all this just by popping my head in and looking around. It's a mess and I don't know what to do. It looks like the flexible duct I could see has serious problems. I can't believe anyone in their right (or wrong) mind would think putting flexible ductwork in attics of homes in suburbs of Phoenix, AZ -- a desert -- is a good idea.

I don't see how there can be rigid metal beneath, which is what is necessary. I had that in the attic of my previous house, and other than issues with non-service of my heat pump for years by a company I paid to actually service it, heating and cooling was great and my electric bills were low.

But since I moved to a smaller home, the electric bills have gone up. I've had energy audits. Everyone says I need my ducts sealed and new dampers, but they won't go into the attic and they won't tell me how they will access the ductwork. Everyone says the ductwork is probably leaky. How do they know there is even ductwork there if they can't see it?

Are they just guessing? That's what I'm thinking. So I don't know what to do.


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RE: cost to redo ductwork...wow!

If the person tests each supply and return and measures the airflow in cfm and the supply comes up to 700 cfm and the return is around 120cfm and the system is @1200 cfm (3.5 ton) its pretty easy to tell their is a huge problem. I did the work myself and even though its tedious it makes a huge difference in $ and comfort.


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RE: cost to redo ductwork...wow!

"All the companies that do these audits give you estimates for work they would do to improve energy efficiency."

that simply isn't true. not all audit/rating businesses bid the work. some of us just provide inspections, testing &
present homeowner with options & scope of work to be done. once work is done..we come back..re-test,
re-inspect & verify efficiency of what you had done.
or what you diy.

sounds like your "audits", are the low cost or free ones.
you get what you pay for.
if someone is not testing the house with a blower
door & testing ductwork you haven't had a rating or
an audit.
maybe a 'walk thru' inspection..but not an energy rating.

visit www.resnet.org
professional independent third party verification
energy ratings.
hire & pay someone to do an energy rating.
then you'll have an idea of what is going on.
as it is...you don't have a clue, other than high
utility costs.

your post sounds frustrated & angry..and I get it.
but unless you are willing to diy the work...then
you have to get someone to actually get into the attic
to see what is going on.

flex duct isn't uncommon. all duct systems are not
sheet metal. at 3x the cost of flex duct, many people
chose flex over sheet metal. when installed properly
it can be a great duct system.

average duct leakage is 30%, so sealing ductwork
is a great savings with a quick return on investment.

underneath the insulation on the attic floor
are ceiling joists. you put boards down on top
of the joists & go to the plenum & check out what
you have.

take some pictures & post them
we can help you diy, on this site.

best of luck.


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RE: cost to redo ductwork...wow!

katvil gave new life to a 19 month old thread, should've started a new one.


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