On Thu, 3 Jun 2004 08:23:29 -0400, "CBhVAC:\)"
wrote:
"Chris J..." wrote in message
.. .
On Wed, 2 Jun 2004 23:44:32 -0400, "CBhVAC:\)"
wrote:
"Chris J..." wrote in message
.. .
And I am looking for criticisms, thanks. I'd rather find out here than
after I rip holes in walls whether this idea will work or not.
NP...installed, and ripped out and RE installed more units than I care to
remember...I have a pic on the office wall on my last evap install...on a
rooftop in CA, and everytime someone asks me about one here, I tend to look
at it and go....No.....way.....
If I had any sense, I'd probably shy away from doing this project
myself... :-)
You got UpDucts for this too right??
No, I don't. I was planning on replacing some attic access hatches
with screens during the summer months (would that count as an actual
upduct?) . The attics are all ridge and soffit vented. I was thinking
that air flow through the attic would also help cool the house.
It would, but an UpDuct is a barometric duct. You dont have to worry about
heat from the attic, putting a cover back in place, etc....you just put one
in each room that you want cooled, or two, depending on the size and area,
and the amount of airflow you have from your ducts from the cooler, and when
the cooler comes on, badda bing, you have no windows to open, no doors to
worry with, and a cooler home.
Could I fit those into the attic access hatches? The hatches are just
sheet drywall, but I could replace that with wood or steel and paint
it.
And the #1 design of western AC ducts...(Drumroll please.........) is what
you describe. Now, granted, Ihave said it before, and will say it again, *I*
cant see it from here, but I can promise you one thing....AC ducting, is NOT
adequate 99% of the time for a swamp cooler.....particularly a MasterCool2
unit.
moved from lower down
Ok..heres something to think about...6 inch duct....100CFM...roughly.
Depending on the tonnage of your current AC, you prob have either 8 or 6
inch take offs going to each run to the room.
Unless you have about 20 of them,
More like 40 of them...
The reason I thought mine might be adequate was that the configuration
is different from most I've seen (I'm a realtor so I see a lot).
On top of the Trane unit is what I call the "main junction" (Sorry, I
don't know the correct terminology for any of this). It's basically a
square box, and out of it come three "main ducts", which are approx
12"X24" (giving me an outgoing ductwork cross section total of about
six square feet). one of these "main ducts" has five wall registers
directly into it and also a few standard floor registers on six-inch
pipes. The other two have smaller standard floor size registers, off
of 6" pipes. There are a total of about five large wall registers, 25
floor registers on 6" pipes, and a dozen more even smaller registers
(such as under-cabinet, bathroom, etc.) on 4" pipes.
When the blower on the Trane is running full power, the air (hot or
cold) comes out of registers more like a draft. But, one nice thing is
it's totally silent.
If you still think this is insufficient ducting, I'll scrap the
project, but I just wanted to be sure I'd described it adequately.
Other AC installations I've seen have just one or two of the 12X24 or
similar sized ducts coming out of the main junction. I've never seen
four before.
added from your other post
It wont make any difference at all to the life of the unit, unless of
course, you have a 40 year old design....
Been down this discussion before...
Thanks.. you just saved me a major job, if I do end up being able to
put in the cooler.
Also, if there is some flow through the AC unit and back out the three
AC return registers, that effectively adds to my ductwork capacity.
That's an option... I'll have to phone Trane and see if they have a
SEER rating for my present system (XL 80, about ten years old) as I
can't find one anywhere on or in it, nor on the web (everything on the
web I've found is for newer XL 80's). (this unit was present when I
bought the house, so I wasn't involved with the installation). If I
can get significantly higher SEER, I'll do it if it isn't too
expensive.
10 year old XL80 would be a max if 10SEER, the lowest rating there is
currently. ARI has jumped the min standard from 10, to 13 starting Jan 1st,
06. In your area, a 14 SEER would actually be a big jump now, and in a year
and a half, it will be the equal to todays 12 SEER.
Does increasing the SEER by 40% roughly reduce electrical usage by
40%, or am I misunderstanding the ratio here?
Due to the age of this system, I'd be willing to spend a few grand for
a new, high-SEER one to save 40%, but I wouldn't to, say, save 10%.
If that's the case (not doubting you, but my ductwork capacity looks
larger than in similar houses I've seen) then that sinks my idea.
Thanks for tipping me off to this potential problem.
Ok..heres something to think about...6 inch duct....100CFM...roughly.
Depending on the tonnage of your current AC, you prob have either 8 or 6
inch take offs going to each run to the room.
Unless you have about 20 of them,
I've got at least that, plus several larger registers that are
installed directly into the box ducts.
6 inch would be too small to properly get
enough airflow to each room, and be able to benefit from the
cooler.,...unless you are installing a tiny unit....and even then, its a
possibility that they are too small for that.
Most installs even with the smallest MasterCool unit or similar, used a min
of 8 inch duct, and most were 10, some even as large as 12...evaps need, and
demand airflow. in, and OUT of the home.
Why wouldn't a larger number of smaller ducts equal a few larger ducts
in capacity?
No. Thats called in the trade, just damn stupid.
It is also very illegal.
I didn't mean attach to the water heater "chimney", but rather to the
duct that vents the utility room into the crawlspace, basically just
extending it a little. Or is that what you thought I meant, and it's a
bad idea (and illegal)?
No..I know what you mean, and what you propose would create a negative
pressure zone, OR, the possibility of it.
How? The utility room would be isolated from the crawlspace by what I
propose. The Utility room would be vented to the exterior instead. (by
running an airtight duct through the crawlspace to an exterior wall),
so how would it be different from venting the utility room elsewhere?
Other then the present vent duct from the utility room to the
crawlspace, there is air connection between them (they are not even
adjacent). I'm not trying to refute what you say, I'm just making sure
I didn't explain myself badly and give you a false picture of what the
end result would be.
You cant do that. Your water
heater is going to fire up at some point when the coolers running, and all
that exhaust, will be pulled into the home.....granted, it SHOULD be heading
right out the open spaces to the outside...but its still not a good idea,
ever, to introduce exhaust gassses to the living enviroment...its also very
illegal.
Agreed that I definitely don't want any chance of exhaust gasses in
the house.
Which part? Putting an Evap in a crawlspace, or the ductwork issues,
or both?
The crawlspace idea, while novel, might run into a couple of issues....its
going to depend there on your inspections department. The
ductwork...Umm...doubt anyone there in the department has a clue about
that....its the gas water heater issues that I can see that kill the idea
from the word go.
Unless I can resolve the ductwork and the water heater issues it's a
definite no-go. I'm not worried about the gas furnace part of the
Trane, as it's a powered exhaust, and I can't imagine wanting to run
the heater and the cooler at the same time anyway.
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
About the only place in town that sells them, other than installation
companies, is the home depot, and they were the ones who wanted to
base it solely on square footage. (I live in a fairly small town).
Let me explain one thing to you...HD employees are drones....total,
complete, idiots for the most part.
I know that (:-)), but they also are about the best informed people in
this area. (says a lot for the area, huh?).
Go to the website for the brand of unit you are looking at, Adobe and other
brands all have a sizing chart that is fairly simple to understand.
I'll go to several, thanks!!!!!! (I have no idea on brands yet so I'll
check several)
I've been told it is, but I disagree as it works fine, or seems to. It
does not run anywhere near continuously (more like 10-15 minutes an
hour in severe heat or cold) unless I've just turned it on and it has
to make a major change in interior temperature.
The ONLY way to know, is to have a manual J load calc done....to insure its
proper. Too large of a unit will short cycle, and cost you more to run......
If I understand the term right, I'd need to hire someone with a lot of
experience; there are too many unusual factors here (it's kind of a
weird house, but I like it.). The construction is non-standard in many
areas; multiple roofs of different (and non-conventional)
construction, exterior walls of non-conventional construction (and
also in some cases non-vertical) several custom made windows of odd
design and shape (such as protruding half-pyramids) etc. Walls with
alternating brick overlayed by polished granite, and conventional
frame construction in diagonal bands (which change in width as they go
up, making it worse), etc. No way I know of to figure R-values for
much of it.
When I had my AC serviced last year, I asked about calculating the
correct size, and the service guy (from a place that does
installations) looked around and shook his head, telling me he had no
idea how it could be done.
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.
I managed to break $200 in Phoenix in a small apartment on more than
one occasion, but I suspect that was a cheap AC unit.
Or sized wrong..
See it all the time.
I remember the AC ran just about continuously on hot (over 115) days.
That would indicate a wrong size, if I'm understanding correctly?
One problem with this house is the design; it's sort of staggered up a
mountainside, so it has a disproportionatly large surface area. It
also has a large cubic area due to having twenty foot ceilings in some
areas. It also has a heck of a lot of windows and walls with full
western exposure.
$200 was for a month with record heat. $70 to $110 is more common (but
that's just the increase caused by the AC, not the total electric
bill).
Thanks for your comments and help.
No problem, but keep in mind, that you have other alternatives still yet to
consider.
Just curious...how much attic space do you have?
That's complicated. I've got three main attics, and a couple of
smaller but separate attic-type areas. The attics (most of them) are
odd because the interior ceiling is peaked, but the exterior roof is
peaked at a sharper angle, so it's a weirdly shaped space. Kind of
like an inverted V under a taller inverted V. The attics are separated
due to the odd design of the house (the house is three stories,
staggered up a hillside, so parts of all are ground level but in some
areas the stories overlap) Some parts of the house have no attic (wood
ceiling, a couple of feet on insulation, then the roof directly
attached) but others have attics. Total attic square footage is around
900 sq. ft, with an average height of (guessing) two feet, but going
from a few inches near the Soffits vents to a few feet under the ridge
vents. All are accessible.
Are you thinking of putting the Evap cooler inside an attic? There is
space, and I did think of that, but I didn't think it would work. The
attic interior is warmer, and also the utility room is in a part of
the lowest floor that would have a three story vertical with a few
zig-zags, then a twenty foot horizontal run of duct to get from the
cooler to the main ductwork junction in the utility room. Not only is
it a long way, but installing the duct would be a truly massive
project, far, far more than I'd ever want to attempt.
Thanks again!
Chris