On Jun 17, 7:47*pm, wrote:
On Thu, 17 Jun 2010 16:18:54 -0700, "Nonny" wrote:
We've been looking at homes here in the Las Vegas area and I've
noticed something that seems different from other areas where
we've lived. *In many of the newer homes we've visited, there are
2, 3 and even 4 furnaces, each with split A/C units; I would have
expected to find just 1 or perhaps 2 units and then zone dampers.
Which would be considered to be a superior system?

One thought is that its possibly considered more energy efficient
to install (4) *2-1/2 ton to 4 ton units than to install a couple
4-5 ton units and then have dampers up in the attic, where it's
both hotter than Hades and difficult to reach for maintenance.
Could this be possible? *I find it difficult to believe that
purchasing and installing 4 furnaces and A/C units is less
expensive than one or two larger ones with zoning.

Would a system with 3-4 individual, smaller, units give better
humidity control (hint: it's 6% RH here today), better energy use
or better energy management? *The systems we've seen are all on a
typical VAR meter and not a TOU/Demand meter.

What gives?

Nonny

I have 3 A/C systems in my house. One central system would probably do
the whole thing but I just use that to keep the house livable (set
fairly high and on a timed thermostat that goes higher). Then at night
we have a separate mini-split in the bedroom we only use when we are
sleeping, set pretty low. The 3d is in the back room that we seldom
use and do not really air condition unless the kids are here.
Mini splits are getting so cheap, the payback is fairly fast and Obama
will give you 30% back right away.

Got a good site for more information? These sound like a reasonable
option for the currently unfinished space over my garage that I'm in
process of converting into my shop. I was just going to tap into the
upstairs air handler (it's in the area, already), but this may be an
even better solution because it would help keep dust out of the res of
the house. Perhaps simpler, too.