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Tony[_19_]

wrote:
On Jun 28, 5:42 pm, Tony wrote:
wrote:
On Jun 28, 12:39 pm, Tony wrote:
Steve B wrote:
"Tony" wrote in message
...
Steve B wrote:
"LouB" wrote in message
...
Tony wrote:
Bill wrote:
"Tony" wrote in message
I'm trying to figure the cost of running the central AC in my house.
If your heating is other than electric, then the cost is the
difference in your electric bill from the winter to the summer.
Or if there is a month in the spring when you don't use heating or
A/C, then the difference in the electric bill from that month and a
summer month.
Hint: If you get a couple of window air conditioners and just cool the
room(s) you are using, the cost will be lower. So just cool the living
room during the day and just cool the bedroom at night. If you have 6
kids and 7 bedrooms, then not much savings of course!
That's exactly what I getting at. I'm almost positive it costs less to
run 1 or 2 8,000 BTu window units than the central ac, even if I close
off the rooms not being used.
I suppose if I compared oranges to oranges and converted both central
and window rattler to a basic BTU's/watt that would be very helpful,
but I still need the specs on my compressor.
Have you sought help from your electric company?
Have you looked on your bill and read the $/kwh? Compared the chart for
month to month, and this year vs. last year comparisons?
Yes. But comparing last years to this years has too many variables.
AC, in my estimation, has to do with keeping things cool. Once a room is
cool, it takes less power to keep it cool than to cool it down from warm.
I'm with you there.
With central units, they will do this better than room units that have to
cool a warm room. Up. Down. Up. Down.
No up down up down here. In this 93F weather the little 8000 BTU unit
runs on high 24/7 unless it gets too cool, then I turn it down. Cycling
it makes it less efficient.
But, then, the only way you find out is to install central, and do a post
mortem analysis.
I have central. I believe it costs much more to operate than a window
unit or two, but it's hard to say without the right numbers.
Right now I have one 8000 BTU unit and one fan to circulate the air.
Running it 24/7 30 days would cost me less than $60. It never runs all
night so it's maybe $45-$50 a month to cool 960 sq ft. Forgot the fan to
circulate the air, add about $4. per month.
Sometimes a large central AC won't have to work as hard as several
smaller ones. But then, there's the thing of cooling unused space
......... It's hard to say.
I always considered "work as hard" an odd expression in this context. I
had a Fedders, maybe 7000 btu run pracically 24/7 each summer for 15 years
and it never stopped working. I left it at my old house because it wasn't
nearly as efficient as the newer ones.
But as you say, there are so many variables ...... insulation, reflectivity
of roof, roof venting, single or dual pane windows, airtightness of the
structure, even natural shade tree placement.
No wonder you say it's complicated! I'm talking about using the same
house for both *tests*, factoring in the weathers "cooling degree days".
You have asked a complicated
question with no answers,
I didn't think my question was so complicated.
What is the rated current draw on the compressor I listed? That's all.
It seemed like somewhere there would be an easy answer, another web page
maybe? I guess not.
The answer as to how many amps the compressor is rated out may not be
complicated, but it also doesn't answer the question you are seeking,
which is how much it cost to run your AC.
If you want to know how many amps the compressor is actually drawing,
just buy a cheap clamp-on amp meter from HarborFreight or similar.
They have them for around $12. But that leaves out power factor and
how much the rest of the system, eg blower is using.
As I and others suggested, why can't you turn off any loads that might
come on, eg electric water heater, attic fan. refrigerator, etc, then
run the house for a couple hours of continuos AC and a couple hours
without AC and record the electric meter readings. That will give
you how many Kwh it takes to run and you'll be way ahead of where you
would be with the amp rating of the compressor.
Like I said before...
A couple hours run time using a kwh meter with an accuracy of +/-
19Kwh??? That may show my AC runs for free.- Hide quoted text -

- Show quoted text -

Have you even taken a look at your electric meter?

Yes many times.

When that AC is
running, the meter is going to be flying and in a couple of hours you
will indeed have enough usage to increase the least significant digit
or two digits, substantially. Certainly enough to get a good enough
reading to determine the approx cost of running the AC continuosly for
those two hours.

Sorry, my meter doesn't do anything fast. It's not mechanical and the
little fake LCD "spinner" thing doesn't move fast either. To read my
meter you must multiply by 20. If I stand in front of it watching, the
number changes 1kWh for every 20kwh's used.

There is no way you could falsely conclude that
it's "running for free."

If I read it only an hour apart it may very well have the same reading.
It may have the same reading for hours! If the reading just turned to
0003777, it takes the use of 20 kwh's to change to 0003778. So if it's
been a few hours, it may very well have the same reading it did when
first checked. That is why I said it's accuracy is +- 19kWh. It all
averages out in the long run, but for less than a few days or more, it's
not very accurate at all.

Assuming you did what I suggested, which is
to turn off any other large loads that might come on, ie electric
water heater, pool pumps, etc. just taking the entire usage during
that test period and counting it as AC usage isn't going to be too far
off. Think about how big your ENTIRE bill is during months with no
large loads, ie no heating, no AC. Divide that down to 2 hours, and
it isn't much compared to what the AC will use.

If you want to get a better read on the low usage from the rest of the
house when the AC isn't running, measure it for 8 hours, or whatever
it takes to move the meter enough to get a good reading. Or better
yet, just open all the other freaking breakers so there is no other
load other than the AC for two hours.

Two hours isn't nearly long enough and it would be tough to turn off
everything else for a couple of days.

This ain't rocket science.

It seems to be, since no one seems to understand how my electric meter
works.

All I asked was how much power does my compressor draw. I already
figured in the fan and blower motors, I just needed to know what the
compressor draws.

As someone suggested, I didn't buy it yet, but I put an "amp clamp"
meter on my Harbor Freight shopping list. So thank you to everyone who
replied and I will take the advice of getting an ammeter (and an hour
meter to keep track of how long the AC is actually running).