"Chris J..." wrote in message
...

I'm thinking of adding evaporative cooling to my home, and none of my
local stores seem to know much about it regarding a non-standard
installation. So, I thought I'd ask here and see if anyone can spot
potential problems I've missed.


You asked..



The reason I want to install an Evap cooler is to reduce my electric
bill because using my present AC can cost up to $200 a month. I'd
also like to be able to use the cooler on "fan only" as an alternative
to opening windows when the weather isn't too hot.


You got UpDucts for this too right??


First, my install plan;
My home has a combined forced-air heater/AC (gas heater). I was
planning to use the existing ductwork for the evap cooler.

Nope..
Not a good idea. Do what you want, but the ductowrk for the AC isnt sized
correctly for an evap...period.


My heater/AC is in a utility room on the lowest floor of my home, and
ten feet from a wall that divides the living area from a dirt and rock
floored crawlspace (the air in there is cool and dry; no moisture in
the crawlspace at all.). The crawlspace has twelve-foot ceilings in
that area, and I plan on installing the evap cooler in the crawlspace.
(outside mounting is not an option; it would cause too long a run of
ductwork to get to an outside wall. Roof mounting is also much too
far, and in any case forbidden by my homeowner's association.

Then you need to give it up, and purchase a higher SEER AC unit..



Basically, I plan on running the cooler air into the main forced-air
junction box that's on top of my heater/ac. An alternate plan would be
to run the cooler output air into an AC return duct that passes right
over where I want to put the cooler. That would be far easier, but
it's only a 14" round duct and it does not look large enough. Aside
from easy installation, that configuration would also run the cooler
output air through my air filters, which I would like. In either case,
I plan on installing some sort of flapper valve that will close
automatically when the cooler is not in use (so when I'm using my AC
or heater I won't be losing air back through the evap cooler).

Read what I said about AC ductwork not being large enough.



My main concern is that the utility room is vented, via a duct, into
the crawlspace, for ventilation of the water heater and heater/AC. My
concern is that the cooler will create low relative air pressure is
the crawlspace, and thus a reverse flow in the water heater "chimney",
which is a four inch vertical pipe over three stories tall.

If this is the case, could I just attach an airtight duct to the duct
between the crawlspace and the utility room, and extend it thro9ugh
the crawlspace to outside?

No. Thats called in the trade, just damn stupid.

It is also very illegal.


Also, there are not enough air entry points into the crawlspace for
the airflow, so I was going to put a screened cutout in the crawlspace
door (which is on an outside wall).

Plumbing won't be a problem, nor will electrical power. I have a
dedicated 15 amp line in the crawlspace that is used only for one
9-volt fluorescent light. There is a drain line below where I want to
mount the cooler, and also a cold water line nearby, so I do not
anticipate pluming problems. (I plan on putting a drain valve in the
cooler pan, for flushing and seasonal draining.)

I'll be going to city hall to see about permit and code requirements
in a few days, provided this plan still looks feasible. There are no
city or state codes here, just national ones.

And your idea violates the International Mechanical Code...the standard
code.


A few more details; the climate here (mountains of Northern Arizona,
altitude 7000') is usually dry, but in July, August, and September can
be very humid. Daytime temps in the hot months (May through October)
often run in the 90's.

The house is a little over 4000 square feet, well insulated and sealed
against air leakage.

Anyone see any problems in my plan?

Plenty.

Also, how do I figure out what size evap cooler to get?

The evap cooler company can tell you...or, you can just go to Home Depot and
buy the biggest one you can find.....LOL

My present AC unit (Trane XL-80) is undersized for the square footage
of the house, but due to the house having good insulation and being
built into the side of a mountain it works just fine winter and
summer.

Then its not undersized is it? There are NO Rules of Thumb for SF/Tonnage.
If your unit is working, (altho, I have doubts about how well, since I never
broke $200 in good old Palm Springs, nor did my father in law in Phoneix and
he had over 3500SF of home....) then its not undersized.


Thanks in advance.

Chris