My old 1987 ARI Tech book "Summer Outdoor Design Conditions for the
Rochester NY area" is:
2½% Design Dry Bulb is 88-F Coincident Design Wet Bulb 71-F | 85 and 71 is
around 50% Relative Humidity
Therefore, design conditions appear to be less than 50% RH.

First, do everything you can to reduce air infiltration and increase
insulation.
It should NOT take much cooling capacity to handle that latent and sensible
heat load!
For higher SEER efficiencies and low humidity control you need long run-time
cycles!

Do NOT oversize your A/C system!
Make sure they get an optimal heat-=load on the evaporator coil during
normal room temperature settings!
udarrell
--
The Air Side of Air Conditioning -
What BTUH, EER, and SEER is your Air Conditioner delivering? (Optimize
it!)
http://www.udarrell.com/air-conditio...city-seer.html
=======================================
"WhyKnot" wrote in message
...
OK, let me defend myself (and thank you, your advice is good and I
seriously
am learning more on these NG's than from all FIVE quotes I had, and I've
went with at least 3 very reputable long-time companies in the city)
(Clipped)
2- We live between near Rochester NY. We have long, snowy winters and
the
average humidity all year long is above 50-60%. Average low temps in Jan
is
in the mid teens, Average high temps in July-Aug is in the high 70's to
low
80's. Average morning humidity in the summer is around 88%.
The heat and humidity is a real health problem for my child who has a
serious medical condition and ends up in the hospital because of this
problem frequently.

3- I need to have this job done quickly. I've been getting quotes for a
couple weeks. I've check the Better Business Bureau site for any info on
these guys (all are in good standing), no one I ask seems to know anyone
in
the HVAC business...everyone I know used the big businesses for their HVAC
and those are two for the quotes I got; all I can do is take the
references
of the independent guys (and are they going to give me bad ones?).

4- They all told me the furnace I have to way too big, and they are all
downsizing me more appropriately. The only difference is in sizes is the
last quote we had from the Carrier fellow who wants to go with a bigger AC
(3 ton 10 SEER and the others all are saying a 2.5 ton 12 SEER).
And for that person who asked, the Carrier furnace booklet says variable
speed, nothing about 2 speed.

5- I am the type of person who usually researches everything to death
before
I do something. I just can't with this. That's why I'm turning to the
generosity and helpfulness of you good folks in hopes I can get some
guidance here. As I said, I need to make a fast decision on this and I
just
don't have time to research it. Without any feedback, I'm just going to
have to pick one anyway, so there's no harm in asking for a few opinions,
right?
I do appreciate your help and advice.