Replacing my AC system - and my head is spinning

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I have 2 zones of AC in my house, east and west. Both condensers are on the outside sitting on concrete pads. The air handlers are in the attic, hard to get to.
The east unit appears to be replaced in 2000, seems to be a 3.5 ton (?) unit, and cools 4 bed rooms, 3 bath rooms and a 30x20 high ceiling, poorly insulated, with 20' of glass and doors on one side, a total of about 2000 SF of space. It is working, but does not cool enough in the middle of summer. My thought is I need to up the tonnage of this unit so it cools better.
The west side appears to be a 3 ton (?) unit, and cools a living room, dinning room, utility room and kitchen, a total of about 1600 SF of space. This condenser is now broken, out of warranty and needs replacement. I would also like to up the tonnage and add two new supply lines to the family room, therefore the large family room in the middle will be cooled by both zones, two vents from each side.
I asked three companies here to provide some recommendations and quotes.
Company 1 came by, looked around, and told me I have a 3.5 ton unit on both zones and they both need replacement, because the one I have there now, brand name "Janitor", is "a piece of crap" and will break soon even if it does not right now. He recommended that I replace both condensers and air handlers with Trane, a much nicer brand. He also recommend that I leave the air handlers up in the attic because it would be too much work to move them down and all duct work needs to be redone once you move the air handler. He will add two new supply lines for me to the family room. I asked him if I should move the air handlers down, he said no, because you have to redo all the duct work and that adds $5000 or more to the cost. I asked them if the air handlers are in good shape, he said yes seems to, but when you switch condensers you have to switch to the same brand air handlers or else it will not match and you will not get energy efficiency.
Company 2 came by, after inspecting my units, said I have a 4 ton in the east and 3.5 ton in the west. I said I thought both units were 3.5? He said says who? I said I had another company provide me with a quote and he told me 3.5 tons for one and 3 for the other. He said well if you want to hire idiots who does not even know tonnages go ahead. I asked his recommendations and he said the Janitor is not as good but it looks like my air handlers in the attic are in good shape, and I only need to replace both condensers on the outside. He also recommended Trane condensers. So he recommended that I leave the air handlers alone. But when I said I need two new supply lines for the family room, he said "Ah, now it changes everything..." he said to add supply lines I need to add ducts, if I add ducts I should move the air handlers down to the ground. I told him my understanding is the duct work has to be all redone, and he said "nonsense, you can reduct just one main to the new location and reduct the return, that may be extra $600 the most, but I have to run new electrical wiring to it that's all". So he quoted me two Trane condensers, one air handlers stays put, the other air handlers will be bought down into the garage, two new supply lines and reduct existing to new location. I will need to hire an electrician to the air handler location. I told him I heard that the air handlers much be switched out to the same brand to get energy efficiency, he laughed and said "well if I wanted to sell you more stuff I would have said the same thing"...I told him about the new supply lines and whether I need to up the tonnage, he said yes, better go with a 4 ton, I asked him if I need to change air handler to match the 4 ton, he said no, he can change the expansion coil and that would take care of it.
At that point I was tempted to go with company 2 cause he seemed to be more knowledgeable.
Now company 3 came by and said OK you have a 3.5 ton and a 3 ton unit, I said what? I thought I have a 4 and 3.5, and he said no he is pretty sure it's a 3.5 and 3, he dialed his partner in the office and read him some serial code and he put his phone on speaker and his partner said it's 3.5 and 3, he said "see? did someone tell you it's otherwise? I would be really scared of someone who can't even determine tonnages, they are not pros". I asked for same recommendations and he said he would replace both condensers and both air handlers with a higher tonnage, redo all ducts and bring the air handlers down, I said I am concerned if the reducting will cost a lot of extra $, and he said yes, it will but you have no choice, the code requires that you bring it down, no one leaves air handlers in the attic anymore, and he said if I need to up the tonnages, I need to reduct everything anyways because the diameter of the existing ducts would not be correct in size. I told him the other quotes I got do not necessarily require bringing the air handler down, and he said "you will see, it is required, they don't quote you because they want to wait till the inspector comes and tell u to bring it down then they will ask for more $ from you, it's a trick".
All three companies are doing this with permit, and included permit fee in their quotes.
Now my head is spinning, I have no idea whose recommendation to trust.
So my questions are:
(1) Is there anyway I can determine the tonnages myself? Is it possible one person determines the tonnages from the condenser and another from the air handler and they didn't match? I need to check it myself so I know who knows what he is talking about.
(2) Is it true that once you change condenser you need to change to same brand air handler to match? One cannot pair a Trane condenser with a Rheem air handler as long as tonnages match?
(3) As far as whether I have to bring handler down and reduct everything, I guess I have to personally check with the county building department, I am just perplexed that all three companies have such vastly different understanding of what the code requires!
(4) All three companies are large popular companies, have perfect record with BBB and licensed/insured.
Thanks for any comments and sorry for the lengthy post.
MC
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First off, insulate the family room. All off the cooling in the world won't cool that baby.
Second, call someone and just tell them to replace the broken one and leave you alone.
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On Sat, 14 Jul 2007 17:42:11 -0700, Pat

Well that is scary.

I know nothing about AC, but that was what I was thinking. If they do a good job on the broken one, when the next one breaks you can hire them again. If they need it, and they shouldn't, this might be an added incentive to do a good job on the first one.
I didn't understand why you want to up the tonnage, on both of them no less. Isn't this your first summer in the house, and one of them is broken, so how can you know it doesn't have enough tonnage. And even for the one not broken, what about the cleaning of the fins etc. that keeps getting recommended around here. How do you know tonnnage is low unless it's tuned-up? And of course no one here afaict would recommend merely increasing tonnage without doing one of those J or K assessments, whatever. You must have read some of the AC threads here.
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Upping the tonnage is not always the proper solution. Look at adding insulation, check to see that ducting is the way it should be, perhaps change out some of hte glass to low E glass or add some shading to reduce the load and save a bundle of money on the unit as well as operating cost.

OK, you increase the capacity, you cross the supply lines and now you want to regulate that space by two different thermostats. Not to say this can't be done, but it may not be a good solution at all.
Increasing the AC size does not always help cool better, but oversized units can make humidity control a problem. You shoul dhave a Manual J done to see how much cooling you really need.

The brand is Janitrol and yes, it is low end.

A good choice, one of a few possible good choices.

Partly correct. You need the proper sized evaporator coil to match up to the capacity of the condenser. You also need the proper sized blower to get the cooled air shere you need it.

You have to wonder who the idiots really are.
I asked his

He may or may not be correct. Manual D is what is used to determine duct sizes. Adding new ducting certainly does change things, but see my notes above. This may not be the correct approach.

Again, he may be correct, if the lower can handle the new load. What you refer to as an air handlier, is really two parts. One is hte evaporator coil that makes the air cold, the other is the motor and blower assembly that moves the air. Toss in a drain pan, couple of filters and controls, of course, to complete the assembly.

This guy sounds like he really does know what he is doing. My guess is that he is the highest price, but he may give you the best operating system.

You should be able to tell from the nameplate and a cross reference.

Brand is not important, capacity is. Chances are the coils are made by the same outfit in China anyway.

That is what I'd do. No sense in taking chances. Thee are possibilities that old work is OK but new work bust not be in an attic, bt only the actual code can tell you for sure.
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the
You we're doing pretty good till this comment...
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I used to work for a company that made coils. Most every type for heating and cooling, every size from 6" x 12" to 60" x 240". Same exact coil went out the door under different brand names. If not China, Taiwan or Korea does most of that today. .
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You lost your cigar...
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MiamiCuse wrote:

...
Unfortunately, that level of professionalism has been my experience, too.

Yes. and Yes. There are model numbers on both the condenser and the evaporator (part of the air handler). Write down the manufacturer name and model number. Then do some work on the internet to find out what they are. A ton is 12000 BTU/hr. Frequently, two digits of the model number is the nominal capacity in 1000 of BTU/hr. (e.g. xxx30xxx might be 2 1/2 ton). Sometimes, a larger evaporator is used (e.g. a 3 ton evaporator with a 2 1/2 tom condenser). You get a slightly better efficiency, but the condenser determines the nominal capacity of the system. A lot of factors determines the actual capacity.

Not at all. It is done all the time. There is even a database of the actual capacity specs that you get for many such combos here: http://www.aridirectory.org/ari/ac.php

You building department is the best source for what code (or the inspector) requires. Make sure that you get language in the contract with the HVAC company so that they are responsible for doing whatever is necessary to pass the inspector. I have seen HVAC companies charge customers for extra work needed for code compliance.

... As another poster mentioned, you really want to determine your actual load with a Manual J load computation. You may want to consider sizing for the thermal improvements that you are going to make to that large, poorly insulated room. You may then get by without replacing ducts, air handlers, etc. and may cost less.
As for sizing systems, contractors have 2 favorite bad ways to size a system without using thought or effort: 1) If you have a current AC, find the tonnage, and find if the customer is too hot or just right. 2) If you don't have an AC, ask the square footage, and divide by 500.
Good Luck
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the
in
one
air
the
1/2
determines
And his old systems may very well be correctly sized, but now they have issues that are causing cooling problems.
Bigger is not always Better!
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On Sat, 14 Jul 2007 20:04:24 -0400, "MiamiCuse"

IMHO number 2 is the only one who knows what he's talking about. There is no reason you can't mix and match condensing units and air handlers. And there is nothing wrong with leaving the air handler in the attic. I'm not sure how you would determine tonnages if there is noting useful on the unit itself to tell you. I'm surprised the pros all are getting different answers. AFAIK there are 12,000 BTU's in a ton and I thought the number of BTU's was usually listed on the data plate but I could be imagining it. The BBB is worthless. I just had a package unit replaced and went thru the same nonsense with three different companies. The Trane is very expensive. After talking to my bidders I went with a Goodman Brand. It ran about $3000 for a 3 ton unit. The Trane was almost twice as much (different installer's estimate). I also got a song and dance from one guy about the return duct being too small and he's have to replace it. The guy who I went with said it was fine. It must be fine, the tenants haven't called about it since I put ii in two months ago and it's hotter then hell here in Phoenix. It has a Copeland Scroll compressor which is supposed to be one of the best and overall unit looks well made. He said in his opinion there really isn't all the much difference between the different brands anymore and these Goodman were a lot better now then they were a few years ago. I'd ask your number two guy about the cost if you went with a Goodman and see what he says.
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wrote:

the
hard
poorly
SF
summer.
space.
would
room,
zones,
both
air
the
them
He
I
all
the
will
he
to
my
both
two
"nonsense,
that
stays
he
said
need
the
more
sure
really
I
condensers
of
requires
and
I
air
bring
in
one
air
Rheem
I
am
He doesn't say how old they are... and it would be idiotic to use 20-30 year old air handlers with new condensing units!!!!
Ever heard of SEER, EER, COP, etc?????
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Where did I say he should keep his old one? All I said was you can mix and match the parts and a unit in the attic isn't a big deal. It's not rocket science.
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wrote:

on
(?)
2000
better.
quotes.
now,
it
leave
handler.
if
redo
if
switch
it
the
He
and
want
like
replace
he
need
add
my
return,
it
new
an
air
efficiency,
I
change
I
some
3.5
pros".
the
lot
anymore,
anyways
size.
the
quote
fee
possible
who
same
everything,
I
record
year
You said "There is no reason you can't mix and match condensing units and air handlers".
That pretty much says that you agree with the company to use his old air handlers. Is this or is this not what you meant?
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I didn't take it that way. When I read it, I took it to mean only what is in quotes 3 lines up, and I still take it that way.
He didn't say "new condensing units and your air handlers." That might have meant what you think he meant.

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There
20-30
Either way... it's not smart to mix brands!
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kjpro @ usenet.com wrote:

Why? FWIW, I've had a mixed system for years with no problems.
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and
air
Was it an ARI matched system?
What SEER did it operate at? What COP did it operate at? What EER did it operate at?
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Is English your second language? If they are serviceable they can be re-used and used with any brand of condensing unit. If they are in need of work he may be able to just stick a new and potentially bigger coil in what he's got instead of trying to pull the entire old one out. He has options. I never said he should blindly re use the old unit.
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wrote:

are
attic,
about
room,
replacement. I

family
both
on
if
and
move
him
them
else
in
3.5?
quote
So
I
him
to
handlers
two
hire
the
have
I
if
be
unit,
pretty
it's
be
bring
a
to
trust.
the
a
department,
There
20-30
You might like to cobble systems together...
I on the other hand, like to know the system is matched and is operating with-in the manufacture's specifications. This includes having the proper airflow, TESP, etc... it's doesn't include hacking together a system and hope for the best.
Do it right, or don't do it at all!!!!!
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That's a decision for the guy footing the bill to decide.
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