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  1. #1
    Join Date
    Jun 2005
    Posts
    3

    Question

    I have had a few quotes so far on replacing our central air unit and need some help sorting out what’s important in regards to the install. I’ve discounted one already since he gave offhand suggestions without explaining or evaluating anything.
    On the opposite end of the spectrum was a guy who explained a lot about AC systems but also went into an overdone sales spiel. In spite of his over-rehearsed sales technique, the contractor he represents seems solid, good reputation and good warranties. However, I am having a hard time seeing how their quote is 50% more than another contractor quoting the same basic system (a Goodman 13 SEER, 4 ton unit). Here are some items he said were very important that were not mentioned by the “non-sales” guy. Please tell me how much these things matter or if they account for such a price difference.
    1) Insisted we MUST replace the copper between outside unit and AHU in garage. Said that if something goes wrong because of any particles or such in the old line, the manufacturer will not honor the warranty.
    2) Said we MUST replace the plenum above the AHU, and said most contractors won’t even bother with this. He said there is probably mold and stuff in there.
    3) As part of install they will add a layer of concrete to our existing pad to bring it up a little (we have no water problems in that area though)
    4) Said the dark material near one of the ceiling ducts was likely mold, and he would include a treatment for this “free”. Basically blowing some kind of mold killing stuff through the ductwork. Claimed this was worth “hundreds”.
    5) They will check existing ductwork in attic to make sure there aren’t pre-existing gaps, holes etc.
    6) Quote includes programmable thermostat vs. regular digital thermostat of other quote.

    So, the high-pressure sales presentation puts me off (especially when he was trying to convince me to go 19SEER high-end), but I thought he brought up some points worth considering. Though I don’t see how this accounts for such a large difference in the quotes. Any comments on this list? Thanks!

  2. #2
    Join Date
    Feb 2004
    Location
    Maine
    Posts
    483
    You will pay more for a proper install than you will for a poor install. Guy #2 is probably more expensive because he is going to do things right the first time. The cheaper guy may just drop a new condenser in and let here rip. With the cheaper guy he may not care if your ducts are leaking in the attic, after all he's not paying your electric bill. I would be skeptical of any mold treatment though. I'm certainly not an air qualilty expert, but spraying something in the ducts will not correct the problem if you do in fact have mold. You can get this tested to see if it is in fact mold. Correct moisture issues first, replace moldy material, mold won't come back. If it were me and I was shelling out the $$$ then I would replace the lineset, but that is just my opinion. How old is the indoor coil? Might want to replace that too, you won't get 13SEER on an old beat up indoor coil. This investment should last you 20+ years. If it were me I would pay extra to have everything done now, that way you won't have to worry about it.

  3. #3
    Join Date
    Apr 2004
    Posts
    7,680
    That black stuff around the vents didnt come from the vents, it got slapped there in a venturi effect from the air coming out of the register hitting the air in the room. I'm betting your bride burns a candle now and again.

    I think plenums should be replaced also but for many reasons, airflow being paramount. The plenum is the wettest part (other than the coil, pan and drain) in the system and is subject to rot and mold. I like the idea myself. Sprays are worthless for mold, and I would ignore that part.

    Copper, depending on severl things its a good idea. What was the failure mod of the old system? Are you going with R410A? Are they the right size for the new equipment? If its ufficient and not a burnout, then a simple fluching may be sufficient.

    I wouldnt put a pad on a pad, but you know, a set of heat pump pump-ups even for a/c will get the unit up off the ground a little and keep the concrete and unit from contact which can cause rust.

    Inspecting the ductwork is a must and should go without saying but as mentioned, some may not even look at that. He's telling you up front they will and that sounds like an invitation for you to inspect his work when he's done.

  4. #4
    Join Date
    Jun 2005
    Posts
    3
    Thanks very much for the replies so far.
    jdenyer: Sorry if my first post wasn't clear, I am replacing the entire system. I agree that I will pay more for a proper install. But 50% more on a full new system is significant, and I am trying justify to myself what things actually matter within the items mentioned by the contractors. Your points on mold are well-taken. You also mentioned my investment should last 20 years. I am new to Florida and have been told that it would be more like 10 or 15 at most because of heavy use. Is that accurate?

    docholiday: Sir, you are dead-on about the candles; and it the black material is only in the family room where 99% of the candle burning occurs! Regarding the plenums: I will ask the other contractor to add it to his bid as well and see how it totals up. I will also look specifically into the line replacement or flushing option and ask all the contractors to account for it in their quote. I don't mind paying for a replacement as long as I know it's fair. I was told the size of the lines was OK; I guess I didn't like the typical scare tactic sell of you "better" replace the line or the warranty could be totally voided. Sorry, but I don't understand your question about what the "failure mod" was??

    Thanks again! This will really help me decide which contractors are shooting straight.

  5. #5
    Join Date
    Feb 2004
    Location
    Maine
    Posts
    483
    Yes Florida does have a longer cooling season. A properly sized and installed A/C can last 20 years if they are maintained properly. This does not mean you will never have a fan motor or contactor go bad in that 20 years. Even with properly installed systems things can and will fail. A compressor is probably the most durable piece of machinery out there. Compressors can run 20 years easily, if the system is installed properly, charged correctly, and the coils and filters kept clean. Compressors don't just die, they are murdered by unknowing techs that overcharge with refrigerant, undercharge, fail to pull a vacuum when installing, etc. I have refrigeration compressors running today that I installed almost 20 years ago, other than maintenance nothing has been done to these. Homeowners murder far more compressors by not changing filters regulary, let coils get plugged, and failing to have the system cleaned and checked every 1-2 years depending on your climate. As to your contractor choice, choose carefully, you don't want to pay less now, and then find out everything was done wrong and the system doesn't keep you comfy, then you would have to pay all over again I'm not saying the more expensive guy is the better of the 2, I would find out who your neighbors and friends use, word of mouth is a good way to find a good reputable company.

  6. #6
    Join Date
    Mar 2002
    Location
    Concord, CA
    Posts
    2,633
    Originally posted by flguy
    Basically blowing some kind of mold killing stuff through the ductwork. Claimed this was worth “hundreds”.
    LOL! That guy is blowing some stuff alright.

    As far as the rest goes:
    1) Are you installing a Puron system? If so then it's not a bad idea to replace the copper lines. But even then it's not a must.
    2) Must? No. Should? Yes. Mold and stuff? Pfft. There's stuff alright. But whatever. He's just hamming it up to try and make a sale.
    3) I like Doc's answer.
    4) The venturi effect that Doc mentioned is pictured here.
    5) Any reputable contractor should do that.
    6) I didn't quite get that. There are digital stats that aren't programmable. But I can't imagine that other quote actually calling for a digital non-programmable. The cost difference is literally a few bucks.

    There are a ton of things that goes into a good install. This is just some of it. It sounds like you haven't found a good contractor yet. A good one doesn't shovel BS and he would most likely be one of the higher bids. There are a TON things a contractor can do to cut corners.

    I'm wrapping up a job right now in which I was 62% higher than the low bid. And I kid you not when I say that my customer got a bargain. I should have bid more. My on site costs alone were 90% of the price of the low bidder. Does the low bidder do his work on 10% margin? Pfft. He does much better than that by doing crappy work and installing crappy materials. Learn what it takes for a good install and find the contractor that does all those things and doesn't bury you hip deep in bull in the process.

  7. #7
    Join Date
    Jun 2005
    Posts
    3
    Irascible: Thanks for all the info and links. No, I'm not installing a puron system. Re: #6, I meant to say the higher quote included a programmable thermostat and the other didn't.

    I still have other contractors coming out. I want to get a quality install and am willing to pay for it. I won't automatically accept the highest bid nor automatically reject the lowest bid. I'm just looking to understand everything involved. Fortunately, my AC is still working (knock on wood) and I have time to properly compare.

  8. #8
    Join Date
    Feb 2004
    Location
    Maine
    Posts
    483
    Originally posted by Irascible
    Originally posted by flguy
    Basically blowing some kind of mold killing stuff through the ductwork. Claimed this was worth “hundreds”.
    LOL! That guy is blowing some stuff alright.

    As far as the rest goes:
    1) Are you installing a Puron system? If so then it's not a bad idea to replace the copper lines. But even then it's not a must.
    2) Must? No. Should? Yes. Mold and stuff? Pfft. There's stuff alright. But whatever. He's just hamming it up to try and make a sale.
    3) I like Doc's answer.
    4) The venturi effect that Doc mentioned is pictured here.
    5) Any reputable contractor should do that.
    6) I didn't quite get that. There are digital stats that aren't programmable. But I can't imagine that other quote actually calling for a digital non-programmable. The cost difference is literally a few bucks.

    There are a ton of things that goes into a good install. This is just some of it. It sounds like you haven't found a good contractor yet. A good one doesn't shovel BS and he would most likely be one of the higher bids. There are a TON things a contractor can do to cut corners.

    I'm wrapping up a job right now in which I was 62% higher than the low bid. And I kid you not when I say that my customer got a bargain. I should have bid more. My on site costs alone were 90% of the price of the low bidder. Does the low bidder do his work on 10% margin? Pfft. He does much better than that by doing crappy work and installing crappy materials. Learn what it takes for a good install and find the contractor that does all those things and doesn't bury you hip deep in bull in the process.
    Irascible, that's a really cool website that gives the homeowner a lot of useful information.

  9. #9
    Join Date
    Mar 2002
    Location
    Concord, CA
    Posts
    2,633
    Thanks. I've been thinking about charging admission.

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