Ductwork A/C questions

15 years ago

I am installing a 3 ton split system and have received @ 3-4 quotes from Carrier & Lennox dealers for the install. I did my research on the SEER and all the other ratings and I am looking for a good two stage condensor unit w/ variable speed blower....Since I live on a barrier island,outside of Charleston SC, I need to by a good middle of the road system unit as the salt air ruins these units in under 12 years, and the payback ratio for a top of the line system would not be there. I am satisfied with the dealer's quotes but I have a problem as follows: Only one dealer really pushed buying new ductwork and claimed that the new system would not work as well or could not guarantee any efficiencies... Actually this same salesperson quoted all the products to me...air purifiers, Uv LIghts etc...and insisted that I buy them to have the better system. Here's the problem, I have a very low peak roof and most of this stuff wouldn't fit or be very hard to install- the salesman also told me that after year one, I could discontinue using the "in line air purifie" etc...if I didn't like it. He told me that I need to but it to receive all the company rebates. I don't have animals that make the air less than pure and the attic is well insulated with no mold nor mildew etc...Also the ductwork is less then 18 years old and prior to the Heat pump system needing replacement, I was pretty comfortable in my home using existing ductwork. I will be buying the air handler that goes upstairs and the outside unit, creating the heat pump split system, and I am moving away from Heil Mfr. to a Carrier or Lennox only because of the installers in my area, I'm not knocking their product. Do I absolutely need new ductwork as well? I purchased my parents home from my brother's when My Mom Passes away recently,and now I am renovating quite a bit, as time was spent on nursing aging parents instead of home maintenance--so, lots to do with not so much funds being tight from medical bills. I am starting renovations with a new A/C system and storm doors etc.. Could really use your assistance here from the experts in the field on the ductwork. I don't have any problems in the attic such as animals in the attic creating holes in the ductwork or damaging it and from what I can see, the ductwork looks okay as it is all sealed etc...I do like the prices structure for the rest of this companies quote- after I remove all the extras, but I am thinking more that he was just trying to sell me everyting in his book. Can you assist with some suggestions. I don't want to get in over my head. also I am considering moving the air register from the side of the hallway to the ceiling of the hallway as this gives me back a large cabinet. All companies quoting told me they can do this- but does it help the air flow, or any other advantages that anyone can think of? Thanks Ladies and Gents!

Sort by:Oldest

Comments (4)

ryanhughes
15 years ago
If the ductwork is properly sized, and kept you comfortable in the past, it's probably in decent shape. You'll want to make sure it's well sealed and insulated, and also has plenty of return air.

Since you're in a salt water environment, I highly recommend you purchase one of Trane's heat pumps. They have the best coils for this environment. Also, their registered warranty (within 60 days of purchase) is 10 years. If you're within 1 mile of the seacoast, you'll need their required salt water kit, though. If not Trane and you liked the Lennox dealer, I'd go Lennox.

If you're looking at the federal tax credit, not all heat pumps qualify despite what the manufacturer advertises. Please post the model numbers you've been given--indoor and outdoor--if you have them.
climateboy
15 years ago
As far as your ductwork, is it metal or fiberglass? You can't clean fiberglass. Trane and American standard are good units but for the extra price and the fact that you are looking to save money, it might be a great Idea to check with a Local NuTone, Tappan, or Westinghouse Dealer. These are Nordyne produts. You just might be able to get yourself a 16 seer Split heat pump with a Var speed blower motor on the indoor unit, and a 2 stage compressor on the outdoor heatpump. Since this system would qualify for the tax credit you would get $1500.00 off, or look at it like this. You would get free ductwork. All this for what you will most likely pay just for the Trane system. As far as warranty, Trane nor Carrier can touch the Nordyne products warranty If you go with the Nordyne you will get 10 years all parts and 10 year quality Pledge. If the compressor fails for any reason within 10 years, you don't just get a new compressor you get the entire outdoor unit along with labor allowance to replace it. Also the outdoor fan motor on the nordyne never has to be oiled. Trane just gives you a new compressor. Better warranty, more for your money, less maintenance. One more thing you don't need a seacoast kit for the Nordyne product. www.nutonehvac.com
check out that website and you can see pics of the units.
Related Discussions
New build--heating and A/C question
Q
Comments (14)
Tracey - some points of reference for out local climate/economy Nobody uses anything but flex duct at R8(code in attic and used elsewhere for simplicity). Our original HVAC budget was $13 and we spent $20. One contractor was $30 for metal ducts. Original was Seer 13 with no frills. We got Seer 15/16 Heat pump with gas backup down/electric up. Variable speed. 2 stage. Zoning. Total of 7 tons - 4 down, 3 up Your specs are typical in that they are not very informative. They don't give size - usually what they'll do is say that they can maintain 20 degrees cooler than outside and ?? degrees warmer. If you have the $$, seer 15 is generally worth it. I think dual fuel (ie gas and HP) is worth it. Variable speed and 2 stage are more comfort items - worth it if they are worth it to you (the other 2 are worth it in $$ saved). If you have the land and the $$, geothermal is worth considering. To throws numbers around, I suspect we would have spent $40 for geo - down to $27 after tax credit. If you have land, the geo should be less - perhaps down to $20 after tax credit. You can then not have gas, longer life of Pumps, quieter operation, no external pieces and of course energy savings. Geothermal is the one of the few options for tax credits on new construction. In my situation, the money saved was not worth it in just $$$. Lastly - there are a few items for our climate worth mentioning (forgive me if I have done this before). R-40 in the attic cost me $200 and reportedly saves $50 a year (code is r-30). Radiant barrier in the attic gave similar numbers. Energy star certification cost me $850 (or so) but saves me 5% on gas and electricity for life (Progress Energy and PSNC) - payback about 8 years. The extra insulating they do with energy star (cost hard to figure) all makes a ton of sense - mostly using foam around windows and doors - which I think cost $200. They also install backing behind tubs/soffits/on attic walls - that is hard to figure cost of since it went to the framers
...See More
need to replace A/C in Dallas, maybe furnace, other questions too
Q
Comments (5)
Hi, just had a complete system installed yesterday. I live in dallas where cooling means more than heating. cost 7k even for everything. here is a list of what was installed. Trane XR13 4 ton AC condenser. Trane XR80 5 ton 1 stage with 4 speed blower. New matching evaporator coil with the new R-410A refrigerant. New return and supply plenums, all sheet metal construction with exterior wrapped insulation. New manual air dampers at each supply duct. Added an extra return air duct, grill and filter in double existing volume of return. New drip pan with overflow float switch (cut off system if drainage get blocked - keeps ceiling from getting water damage). New electrical disconnect and wiring (located outside by the condenser). New concrete pad. New programmable thermostat. Did all the work required to rid and clean system of old coolant, hauled away old system and did a relatively good job cleaning up. This new system is so much cooler and better airflow than the old one and should be more efficient. I really wanted the sheet metal plenums with EXTERIOR insulation and the manual dampers. This should really pay off in the long run for comfort and health. Next time I should just have to replace the AC condenser. Furnace later. All in all I think I got a good deal and I'm pretty sure the work is A+. I paid a little extra for the plenums, dampers and for Trane products.
...See More
Ductwork through joist question
Q
Comments (5)
If your talking about cutting into that 6x6 on the picture, dont do it. That's a pretty beefy piece of structure probably holding a fair amount of load. Hard to tell orientation and what it supports from the picture though. I couldnt see anyone putting that large beam there just for the heck of it.
...See More
Question about return and supply ductwork
Q
Comments (1)
The general answer is yes. The supply air flow is limited by the amount of air the return flow can provide. In practical terms most installations have undersized returns and air filters. An 18 inch round duct would be needed for about 1600 CFM of air flow.
...See More
veesubotee
15 years ago
"I was pretty comfortable in my home using existing ductwork. "

As Ryan said, "If the ductwork is properly sized, and kept you comfortable in the past, it's probably in decent shape".

Are you replacing a 3 ton with a 3 ton? If so, no problem. It sounds like the contractor is looking to pad the quote. Is he proposing drastic changes to your duct system? If so, he should detail them on the quote.

V
udarrell_2007
15 years ago
Charleston SC, summer design DB92-F WB78-F 54%RH, higher than most.

I didn't see the sq footage, but with that humidity level it is critical to have a tight home. Blower-Door test would be great.

After all the retro work is done, a manual J should be done

"It is very important Not to oversize the Heat pump," or U will have humidity problems, U need long run-time cycles.

Study the linked page below & the one for customers up near the top. -udarrell

Here is a link that might be useful: AC & Ductwork Sizing

Ductwork A/C questions

Comments (4)

ryanhughes

climateboy

Related Discussions

veesubotee

udarrell_2007

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US