keith wrote:
On Jun 18, 10:15 am, jamesgangnc wrote:
On Jun 18, 10:56 am, keith wrote:



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.- Hide quoted text -

- Show quoted text -

Just search, you'll find plenty of them. I don't think they are all
that cheap yet though. However if you're making an upstairs shop
having it's own system is probably a good idea in general.

I see plenty of them, but there is little real information (or perhaps
too much, spread all over). I'd like to know what the installation is
like. What sorts of infrastructure has to be in place. Is it a DIY
sort of thing? I see some have done it themselves and then had an
HVAC tech charge the thing.

pretty easy. a small pad on the ground or screwed into a platform on a
balcony or the roof (if flat). you need about a 2" diameter hole in the wall
for the tubes, and i think a 20 or 30amp 240v line. you need a cutoff switch
in a box within reach of the outside unit.

As far as "cheap", they look to be in the $1K region. Just as a
guess, I should be able to get by with a ton (400 sq.ft., perhaps). I
hadn't considered this sort of thing before because deed restrictions
forbid window units. This would be a natural for the shop, but I want
to be able to convert the space to another bedroom down the road (I
may move and a fourth bedroom would be a selling point in a 3-1/3 bath
house ;-).