ac recommendation

[superuser]

I have a 2 story house in southern California. It has dual pane windows replaced within last 7 years. The house is 3200sqft equally split up and down.
It's orientation is front facing east. The walls and ceiling and floor insulation would be whatever the title 24 called for in the late 60's. probably nothing that great (R11). Now there is a 5 ton unit in place right now, it's just old.
What would you experts recommend?
1) size of units?
2) 1 or 2 units?
3) what kind of equpment?
4) would you recommend any attic fans?
I can't think of anything else. I'm sure I missed something.
Thanks in advance.

[Daltex]

1. Use manual J to determine size. Ask your contractor how they determine size and anything other than Man. J or Load calculation then move on. No rules of thumb. Click link at top of page if you want to try program yourself- trial is free.

2. One unit with dual zones or 2 seperate units.

3. Variable speed air handler for comfort. Use the brand that the contractor you like recommends.

4. Search this forum for PAV and ridge vent. Most all agree that passive ridge vents are the way to go. Good soffet ventilation. No powered vents in almost all cases. (I have 2 but will switch to passive)

[beenthere]

As above.
Don't guess.
Get contracts that perform load calcs.

[S_Helton]

What Daltex and Beenthere said.

[superuser]

Thanks for the replies. My problem is I'm new and I know enough to get myself in trouble.
I got one quote,
4 ton unit down stairs - using existing wiring, copper plumbing etc,,
5 ton unit upstairs - all new everything.
new furnace installed in attic.
I guess the question I should have asked it is,
"If this was your house how would you do it and why?
Again thanks for the replies. I hope this will stimulate some great options.

[S_Helton]

You need to edit your post. Discussing prices are not allowed. Read the rules.

[penetr8or]

A 2 stage hp with zoning would be ideal, but it may require extensive ductwork (and then drywalling). It's one of those things that would be easier to recommend your best option if we could see the setup. New construction and a re and re are two comepletely different things.

[BigJon3475]

Thanks for the replies. My problem is I'm new and I know enough to get myself in trouble.
I got one quote,
$xxxxxxxxxxxx.xx
4 ton unit down stairs - using existing wiring, copper plumbing etc,,
5 ton unit upstairs - all new everything.
new furnace installed in attic.
Now, I have $100,000,000 to spend. I guess the question I should have asked it is,
"If this was your house how would you do it and why?
Again thanks for the replies. I hope this will stimulate some great options.

5 years with 6 post....that's impressive...

[superuser]

Big Jon, if you don't have anything good to say, why say anything at all?

[RyanHughes]

I'm finding 9 tons for 3200 sq. ft. hard to believe. Get a couple more estimates. You need a load calculation done to confirm. Variable-speed furnaces/air handlers with single-stage (or preferably dual-stage if budget allows) air conditioners/heat pumps would be the way to go.