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Central Air Q's for the HVAC Peeps--UPDATED W/Quotes

Post in 'DIY and General non-hearth advice' started by thinkxingu, Dec 4, 2011.

  1. flyingcow

    flyingcow Minister of Fire

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    mrfs- is spot on. Not that you didn't know that already.

    Proper sealing of ductwork is often half assed. Sloppy work often is the norm. Leaks will loose A/C or heat and will effect the flow in the rooms. You want all of your return air coming from the rooms, not attic. Be easier(less $$$'s) to cool return air from the rooms than a seriously hot attic.

    I don't even like any flex runs over 2ft. The last 2 ft to the register. What sometimes happens is the hard duct won't fit easily, but the flex will be jammed in tight spots. Squished, used to make 180 degree turns, etc. 5ft is OK as long as its straight and stretched out a bit. If possible i would put an elbow on top of register to make the turn and connect straight flex in between. And check the straps used to tie the flex on, lightly pull on flex to see if it comes off.

    I agree with the ductwork insulated on the outside. Sometimes we would insulate(inside) the first length of duct off of the unit, as stated above this was for noise. It works well.

    BTW- all these points made are alot of times easier said than done. Most generally its a PITA to retrofit a house after it's completely built.

    If possible with hold the last 25% until you have a punch list done, and the system runs for a few days to see if it performs as designed.

    Good Luck!

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  2. thinkxingu

    thinkxingu Minister of Fire

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    Guys, thanks for the info--truly. I called three local mom & pops today, all in my town (I'd like to keep the money in town, if possible). All three sounded like they wanted the job, and it was good talking to them with some information on what I want. Two of the three said they do what I'm asking fairly often, and lately they've been doing them with heat pumps. Those two also said they've had good luck with just cooling the upstairs and letting the cool air drop.

    Only one mentioned brands, and he was all about Trane. So, brand info? I've seen Goodman, York, Trane, and Westinghouse in the area.

    S
  3. mrfjsf

    mrfjsf Member

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    -Trane(American Standard)makes a good piece of equipment. Can be frustrating to work on because they are very different from any other brand. The saying at work goes "It may be hard to stop a Trane, but when it does, its even harder to get it going again". In my experience, parts for Trane can be a little higher than competitors. Would I install Trane equipment at my house, maybe. It would come down to a "how much can I get for my money with Trane vs Competitor A?"

    -York in my experience is a good brand. They build a nice quality product and have a some pretty nice units out right now. They are affiliated with Johnson Controls. Johnson controls is top notch. I would own York equipment no doubt.

    -Goodman is junk IMO. At least the ones ive worked on have been. They are cheaply built (very thin guage metal, pisspoor design, etc). A fellow tech told me Goodman is starting to clean up their act nowadays and building better equipment. Im not sure, I still wouldnt own goodman products. Im sure someone will chime in and sing praises over their goodman furnace, or tell you their neighbor has had their goodman since 85 and it runs just like new. Good for them, maybe they got one of the good ones, i dunno. I still say they're junk.

    -Westinghouse is made by Nordyne. I don't have a whole lot of personal experience with either. Ive not heard anything great about them. Heard they are cheaply made. I would probably steer clear. JMHO

    From all the choices above. I would probably go with York. But thats just me. Do some research, compare bells and whistles, compare SEER ratings, etc.

    I definately respect you trying to keep the business local and give it to the mom and pops. Props to you for that.
  4. flyingcow

    flyingcow Minister of Fire

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    FWIW- In the old days when i did this, Johnson controls were good to deal with. But all I did was install equipment. The Johnson guys would make it easier.
  5. thinkxingu

    thinkxingu Minister of Fire

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    OK, the first of three companies came out today. Here's what they said:
    1. They don't hang the air handler, they put it on a pad made of foam/plywood/rubber dampers. He thinks it's more secure, quiet, and it sits in a pan.
    2. Solid trunk the length of the attic, but he uses some flexible to control noise.
    3. R8 insulation for all ductwork.
    4. One supply in each bedroom, one in bathroom, one in kitchen, one on border of dining/kitchen, one in dining, at least two in living room (one near the stairwell).
    5. Three returns at least: one in each bedroom (so doors can be closed?) one in living room/hallway.
    6. Square vents, as round tend to be noisier, and placed as closely as possible to "wash" the window (never heard that before).
    6. Feels that conditioning upstairs is more than enough as cold air will drop down large stairwell. Suggests I start with that and then look at returns/supplies in basement if necessary.
    7. Thinks heatpump would be great addition, but will price out both.
    8. He uses Trane and Carrier--used to use York, but said they weren't as easy to deal with or something. Agreed with Goodman's past being questionable.

    Love feedback on anything this guy said (above)--like the company story: parents began company in late 60's, all family owned/operated, town residents.

    S
  6. mrfjsf

    mrfjsf Member

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    1. That will be fine, sounds normal. Pan under is good in case condensate pan decides to leak for no reason.
    2. I would want him to be more specific on the amount of feet of flex he plans on using to make the runs off the main trunk.
    3. Good
    4. Sounds ok to me
    5. Just make sure the total return is larger than the total supply (i.e will flow more cfm than the supplies. I think it is supposed to be at least 10% larger, not sure on that number tho.
    6. Never heard of the rounds being noisier. I agree with the washing of the window. Kind of like The air curtains you see in supermarket doorways for a matter of speaking.
    2nd # 6. I agree with that. Just make sure that the system will be large enough to handle a few supplies and returns in the basement if you decide to ever add them.
    7. Cool. Expect a good price jump for heat pump.
    8. We use Carrier almost strictly. Unless we can get a better price on something else comparable or customer requests other brand. Carrier is definately top notch. You never mentioned it as an option so I never suggested. Sorry.

    Sounds like a reputable company!

    EDIT: Forgot to add that Carrier's new Greenspeed line in heat pumps has something to be said for itself. I heard it has been performing quite well in low ambient conditions.
  7. thinkxingu

    thinkxingu Minister of Fire

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    Great, thanks--he was a nice guy and spent a lot of time with me. I'll be sure to ask him about the length of the flex and total return vs. supply.
    As for round vs. rectangle, he was just saying that in his experience rounds need to be larger to be quieter (without whistle?).
    I liked that he was concerned about look/performance as opposed to ease of access/simplicity. Also, he gave me some suggestions on how to mount my dehumidifier in the basement to drain into the washing machine drain, if we ended up still needing it.

    S
  8. thinkxingu

    thinkxingu Minister of Fire

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    OK, quotes are starting to come in. First one (not sure if this is heat pump or not, and my electrician friend will be doing electrical):

    We hereby submit specifications and estimates to:
     Furnish and Install (1) One 2.5 Ton York Air Handler (horizontal in attic)
    o Installed With Emergency Drain Pan And Float Switch
     Furnish and Install (1) One 13 SEER 2.5 TON York Model YCJD030 Condenser (with pad, leveled)
     Furnish and Install All Required Ductwork Per NATE (North American Technician Excellence) Standards
     Ductwork will supply air as follows – One Zone – one supply for each bedroom and each bathroom upstairs. One central return and filter grill for the upstairs.
     Furnish and Install all necessary low voltage wiring, condenser piping, venting, and drains
     Furnish and Install Slim Duct for covering lineset piping on condenser side of house
     Customer Will Be Responsible For All High Voltage Electric Work From Panel To Equipment
     ONE YEAR WARRANTY ON PARTS AND LABOR
    ï‚· Optional Upgrade:
    o To Affinity Series A/C Condenser +$350.00
    We propose hereby to furnish material and labor – complete in accordance with the above specifications for the sum of: $6,340.00 Six thousand three hundred forty dollars with payments to be made as follows – (50%) $3,170.00 deposit at signing of this contract for equipment and materials and the remaining amount of (50%) of $3,170.00 due at startup of second system.

    Thoughts?

    S
  9. mrfjsf

    mrfjsf Member

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    I see no mention of warranty on compressor, nor did I see any mention of duct insulation...did I miss something? 2 Very big deals. As far as the insulation goes, They can say "Install per NATE standards blah blah blah" all they want, but if the customer (you) does not know what NATE standards are, then they can/will likely just slap it together and out the door they go.

    Otherwise I like everything else with the exception of the central return. This is a "no no" in my book, at least around here with summer temps. I have a feeling that the rooms furthest away from the return will not be as comfortable as you expet them to be. A/C systems were just simply not designed to work this way. The ONLY time I would EVER recommend a central return is if structural design simply did not allow for it. In your case I dont think it is an issue and I strongly recommend against it. JMHO
  10. thinkxingu

    thinkxingu Minister of Fire

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    I asked this guy about adding returns to the bedrooms (one installer said he would add them, so I could shut the doors--not sure I understand this) and he said one central return would be fine. I think he said R12 is what he does for insulation. I did think his pricing was a bit high.

    S
  11. woodgeek

    woodgeek Minister of Fire

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    who is going to do the high voltage wiring....that will cost too and they will have to coordinate.
  12. thinkxingu

    thinkxingu Minister of Fire

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    My buddy's an electrician, and since this guy didn't want to quote me the electrical portion--because I have a slightly more difficult request--he left it out.

    S
  13. woodgeek

    woodgeek Minister of Fire

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    R12 is the current standard for rigid ducting in unconditioned space IIRC. I threw unfaced R-30 over my R-12 wrapped ducts after they left.

    Many retrofits go for central return, usually on a upper central hallway. The door comment is that the doorway/hallway provides the return flow, if the door is tight, there will be a slight pressurization, enough to close the door by itself when it is just ajar. In principle, the supply to the room could drop when the door is closed...with a temp change. In my case this hasn't been a problem at all, the 1/2" gap at the bottom of the door provides sufficient return. The rest of my house is pretty open plan.

    If you go with one big return, be careful about sizing. My guy put in too small a grill (24x24") for the airflow, and it made a huge 'air noise' that I could hear all over the house. I made him upsize it to 24x30 (the biggest available filter size) and it is still audible in the hallway, but not objectionable.

    Hard to judge your quote price since it comes down to the amount of ducting fabbed and installed. A cheap guy will put in a ton of flex (bad) with leaky joints. A real pro might do a perfect rigid system, masticc'ed on all the joints and meticulously wrapped to R-12. If the second guy charged you 2x as much, I personally would go for it.

    BTW, you want the ducts masticed. Period. Watch them during the install. Once they get wrapped, you can't see how shoddy a sealing job they did. That is my only regret...I ended up unwrapping my ductwork in several places, sealing the joints myself and rewrapping.
  14. woodgeek

    woodgeek Minister of Fire

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    Make sure to get a heatpump and a decent tstat--I like my visionpro. The simplest/cheapest case, you wouldn't install any electric strip heating in the handler (the wiring costs can be significant), so defrost cycles would be unpleasant...so you would lock out the HP below 35-40°F, and the stat would call your boiler below that. At those temps, the HP would provide very cheap heat (COP~3.5-4). Sized for A/C, it probably won't keep up much below that anyway.
  15. thinkxingu

    thinkxingu Minister of Fire

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    Ok, so that price did not include a heat pump, so I think it's a high estimate. Said he'd include it if we started next week, but not digging the price or one return.

    S
  16. woodgeek

    woodgeek Minister of Fire

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    As much as I love HP's I wanted to temper/explain my earlier statements given your cold climate. South of the mason-dixon line, heat loads and A/C loads are similar, the minimum temps are pretty moderate and I don't understand why ANYONE would get an A/C versus a HP, given that the sizing in heat and cool are similar and the equipment is so similar. In my climate (Philly burbs, tracks NYC metro temps), conventional HPs (i.e. looks like and installed like a central A/C) are not as popular, but it works for me since I tinker with it. I had to oversize--a 4 ton PURON unit carries my (now) very tight 2200 sq ft to ~21°F, and I might spend only ~250 hrs/yr at temps below that. In A/C, I would need a 2.5 ton unit, so I am oversized, and that can limit RH control in the summer. BUT, I get >95% of my winter BTUs from the pump.

    Anyhoo...I think you should price out a HP unit sized for your A/C needs, and not get any electric backup, with an external temp monitor on the tstat that locks it out below 35-40°F and calls your current heating system. Without the backup and wiring, it might be less than $1k more, and would cover your shoulder season heating much more cheaply than something like oil or propane. The ROI would require you to estimate the fraction of your total HDD that comes in above your lockout temp--not easy to calculate, you could probably guess from a monthly climate table if you were mathematically inclined.
  17. woodgeek

    woodgeek Minister of Fire

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    Oh yeah...about the hanging...I have a pan under my unit too. It just hangs a couple inches over the pan, on some unistrut cross-bars held to the roof joists with threaded rod and couplers.
  18. thinkxingu

    thinkxingu Minister of Fire

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    Hey,
    I'm thinking that I would do the size I need for AC, 2.5 ton, and just use the HP when temps are above 40. Anything below, I would usually have the stove going (my electric baseboards with the new t-stats aren't too bad).

    S
  19. thinkxingu

    thinkxingu Minister of Fire

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    Here's the second of three--this guy seems wayyyy off, and I'm not sure why! The other three estimates from this guy only go up! Thoughts?

    Air Design Services, Inc. is proposing to provide the necessary labor, material
    and equipment for the installation of the following:
    $11,540.00
    I. Install one Carrier 2.5 ton air conditioning system with the following:
    * One Carrier 13 seer "Comfort" model 24ABB330 air conditioner
    * One Carrier single speed model FB4CNF air handler
    * Externally insulated duct work system (supply duct and return duct)
    * Registers, grilles and diffusers
    * Installation complete

    S
  20. saladdin

    saladdin Feeling the Heat

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    The 45F is key to remember. I don't know the exact number, but around 45, heat pumps lose effiecency and the "electric strips" kick on which can really raise your electric bill.

    Do research.
  21. saladdin

    saladdin Feeling the Heat

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    Heat pumps require a "special" t'stat. Make sure the 'stat says works with heat pumps.
  22. saladdin

    saladdin Feeling the Heat

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    Not sure, but isn't SEER 13 the lowest rating?
  23. thinkxingu

    thinkxingu Minister of Fire

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    It is the lowest rating, but for two months' use it would be a long time to recoup the difference in money, yes?

    S
  24. saladdin

    saladdin Feeling the Heat

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    You are right. I always forget not everyone has the summers that we do.
  25. Highbeam

    Highbeam Minister of Fire

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    Indeed, do research. Modern heat pumps with 410a can make very good heat down to zero degrees F. These things are becoming as useful as fossil fuel burners.

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