Forgive me, but your reply made me laugh. I agree with everything you've said, except the thought that I would be stressed if it failed permanently in the middle of winter. The only time I might turn on the heat is if my son's family visits and spends the night. Otherwise, I enjoy the lower inside temps during the winter. About 15 years ago I lived in another home in central Florida and didn't even realize I had oil heat in the house.... I never ever thought to investigate turning on heat! I discovered there was actually a working oil furnace when I decided to move! Of course, I did feel a little stupid not knowing.
The biggest issue I'm having is deciding what WILL satisfy ME, as well as finding that totally trustworthy single contractor you spoke about. I'm actually not playing numbers games between the two contractors, I'm trying to decide which one is more trustworthy.
I plan on starting another thread to address a major difference between the two contractors that concerns me. I won't mention it here so the thread doesn't get "hijacked".
FORGET EACH ROOM!!!! You have a 3.5 ton system right now, it's working (moving air). Find out the TOTAL cfm the system is pushing RIGHT NOW and at what static pressure it's doing it at. THE TOTAL. If you are pushing 1000 at .8, you will never push 1400 at .05, .08 or .1
This will tell you if your duct system is large enough!
Always here
So 'splain it to me, Lucy.
Is the point of the air balancing to find out the total cfm output of my existing system? I've read through this thread and that's how I'm interpreting the air balancing suggestion.
My question is, how does knowing whether my current 3.5 ton airflow totals 1200 or 1400 help me know if my ducts will handle the additional air flow from, for example, upgrading to a 4 ton dual compressor Trane XL20i with, for example, a max airflow of 1600?
We have been trying
Always here
OK, now I'm starting to see the point of determining total cfm... in combination with ESP, not just to balance the system. I'd guess if it's only pushing 1000 cfm, for example, it's not operating at 3.5 ton capacity, maybe because the ductwork is inadequate? But if it's pushing 1400 now, one could assume it could push 200 cfm more?
But my basic question remains the same as before... How the h*** does one go about finding someone to evaluate ESP?
I THINK HE HAS IT!!!!!!!!
2nd question: You are in the best place to find that out. Use the search.
Always here
He who? If you mean me (Florida Joy), I'm a she.
If you mean search for a pro using this site's search, it shows zilch in my neck of the woods. Any other ideas where to search? What title does the specialist I'm looking for go by? Mechanical engineer? Building inspector? ????
Part of air balancing is determining total air flow. Along with that checking the static pressure. So you'll know how much air is moving, and if your duct work can support the required air flow for a 4 ton.
Mite want to look here.
http://www.certaincomfort.org/
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Always here
It's fun watching the picture come into focus for folks. She (Joy) seems to be absorbing it pretty quickly.
-So, we know you are short airflow for 3.5 tons, but not how much.
-You'll be installing another return, which will definitely help but we don't know how much.
-We know your weatherization work has lowered the worst case load, likely to about 2.5 tons (still a high number for house size imo).
-It's unlikely you'll install less than a 3 ton replacement unit, 3 ton needs a LOT less airflow than 4 ton.
-If you install a 3 ton 2 stage, low stage will almost definitely have very efficient air flow.
-3 ton 2 stage will put you right smack where you need to be to efficiently carry your meat of the season load with little to no cycling losses.
-If you install communicating equipment it will tell you static at various stages.
So the question becomes, how much further you go to get comfortable that the 3 ton 2 stage is the right decision?
OK, this site lists one in my county, two in an adjacent county. However, they all do commercial/institutional work. They'd do mine, if I insisted, for a price... more than I'm willing to spend.
Still don't see the benefit of basicly doing an "engineering study" on a single story residence. I'm certain the existing ductwork will handle upsizing from 3.5 ton to 4 ton, my FPL energy survey tech said I'd have no problem doing so, as did EVERY SINGLE A/C contractor, even the one today, who I told I'd be willing to pay extra if the ductwork needed to be upgreded. I'm convinced I have good airflow on my 3.5 ton system (since it was repaired last week), and I'm satisfied that my ducts will handle the little extra flow from the 4 ton XL20i.
Don't see the need to add another 25 to 30% to my replacement cost... so enough about ESP and total cfm and air balancing already!
I'm sold on the XL20i 4ton communicating combo with the 950 t-stat. I had one final estimate this morning from another A/C company owner, so I'm now deciding among three contractors whose owners (not salesmen) are offering the same exact equipment, with the same rebates, for significantly different bottomline prices, depending on whether they'll do the electric under their in house EC license, have to hire an outside EC, or plan on getting away with doing their own unlicensed electric work (this worries me).
I opened another thread discussing the electric, so if you have comments on that issue, please use that thread.
Thanks for all your help! I will be posting pix of my old Rheem, which is running great since Wednesday. But I'll likely delay the replacement to see what my electric bill is with the repaired Rheem. Maybe until December, depending on when the Trane rebate ends.
I was posting when you put this up, so I missed it before I posted my decision about not doing air balancing.
While I've decided on the 4 ton XL20i, that's not to say it's what the final solution will be. My contractors WILL DO MANUAL J, which is required by code, but only after I've commited to their company doing the work. If the results come out to 3 ton, we'll go with 3 ton. If it's 3.5 ton or more, we'll go with 4 ton.
and we thought we had you.
you can perform a cfm test by pressure on the supply ducts... a simple incline manometer can be built, or purchased that will show you the pressure on the system.
The TRUE highest cost system is the system not installed properly...
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Did you actually TALK to them? They will be in the house 1/2 hr tops. So they invoice you for an hour. It will be under $ Remember You just want the totals, NOT balancing
Also, you keep talking about "salesman" You mentioned that the one owner had the company since 1975. Thats fine, but tell him to bring his manager or son with hime next time so you can see deeper into the company. Because he'll (they) will be retired 10 years from now.
Also you may not think you don't want to talk to a sales rep.....but you have....and your sold on a 4Ton 20 SEER system. Another sales member is not needed, you sold yourself.
Good luck
Last edited by beenthere; 08-13-2012 at 05:15 PM. Reason: price
Always here
Yep, they charge $ a day with a 1 day minimum. He said they do commercial work, not residential. He was surprised that anyone would ask to do a private residence. He said if my ducts were designed for 3.5 tons of airflow, pushing 4 tons wouldn't be any problem. He said all an A/C installer has to do to verify duct capacity is "measure" the size of the ducts and determine if they're lined up the way they should be.
Both businesses are in the hands of the "sons", but were started by their fathers in 1975/1985.
Yes, I agree, I pretty much sold myself. But, depending on Manual J calculations yet to come from the winning "bidder", I may talk myself down to the XL20i in a 3 ton. It's not over 'til it's over.
Last edited by beenthere; 08-13-2012 at 05:16 PM. Reason: prices