We have typical builder-type of AC units on our Summerlin
(Las Vegas) home. I've been told by a reliable source that
they are around 9.0 SEER. Our summer electrical bills are
in the low $700 range per month, or about $500 for AC after
factoring out the pool pumps and domestic consumption. The
two units are in their 6th summer.

An HVAC contractor tells me that we can save substantial
power dollars by switching out the outside units and the
inside coils to Rheem 13 or 14 SEER units. He said that
RHEEM is probably the most "basic" of the newer systems,
still uses R22 for lower head pressures and has more generic
low tech parts than other systems. He said that it was what
he put in his own home. The difference between the 13 and
14 SEER units is the air handler, which he said he might or
might not be able to use until he does a static air test on
it to see if the blower and ducts are sufficient.

I guess my first question is whether RHEEM is decent, basic
equipment. If not, what brand is recommended?

The contractor also looked at the diffusers in our ceiling
and told me that I should change them out with ones that
offered low restriction. He said I should do this myself.
Is this correct to get a more efficient system?

Nobody.

rheem favorable remarks at:
http://www.toad.net/~jsmeenen/

see:
http://www.buildingscience.com/desig...rk/default.htm

i have a reem central ac ,had it for 5 years now, its a 10 seer. it
uses 1/3 the electricity than my old one did. i was told it has a screw
pump instead of a piston pump and thats why it uses less.so ask about
that. i do keep it clean outside and inside and that thing will put
frost on the dog.no problems with it so far.. lucas

http://www.minibite.com/america/malone.htm

Damn - $700 per month on the light bill !!!!!!!!!!!!!!!!!!! I'd be
packing up and going elsewhere... Mine is about $85 per month, but
then I've only got a 1,600 sq. foot home with no pool...

9 seer possible, 700$ alot of waist. Why go with 13-14 seer , you can go
up to 19.5 seer. Trane has a Seer Comparison Savings Sheet on their
site. I believe 14 seer might cut your bills in half, a 19 seer wont cut
your bills as much as the increase to 14 seer did as the savings are not
linear, they decrease as each higher seer is used. You can also save on
using a VS DC blower motor on a new furnace, apx 25% in electrical over
a regular AC blower. But get the 10 yr warranty. I would not stop
looking with Rheem but check out what else is offered by other
companies. Yes you need a load calculation, and duct test. But also
consider your building, windows and insulation, im sure you have alot of
room for improvement.