I'm trying to figure the cost of running the central AC in my house.
Inside was fairly easy, a 1/2hp fan motor. Outside the numbers on the
plate from the factory are long gone. I found on the fan motor that it
is 1/8hp. Now the compressor.... On it is listed the voltage but not
the amps or watts but it does list the LRA (locked rotor amps) of 105.0
It is a Copeland CR38K6-PFV-370.

I found this site but even this isn't very useful to me only giving me
the RLA of 19. I read the RLA is "rated load amps" and does not mean
"Running Load Amps". RLA being the most current it should draw under
the harshest conditions.

http://www.nordyne.com/literature/8569%20Compr.pdf

Tony wrote:

I'm trying to figure the cost of running the central AC in my house.
Inside was fairly easy, a 1/2hp fan motor. Outside the numbers on the
plate from the factory are long gone. I found on the fan motor that it
is 1/8hp. Now the compressor.... On it is listed the voltage but not
the amps or watts but it does list the LRA (locked rotor amps) of 105.0
It is a Copeland CR38K6-PFV-370.

I found this site but even this isn't very useful to me only giving me
the RLA of 19. I read the RLA is "rated load amps" and does not mean
"Running Load Amps". RLA being the most current it should draw under
the harshest conditions.

http://www.nordyne.com/literature/8569%20Compr.pdf

None of those numbers are of much use in calculating operating costs
since none of those items runs 24x7. All those numbers will tell you is
how big a circuit the items require.

Pete C. wrote:
Tony wrote:
I'm trying to figure the cost of running the central AC in my house.
Inside was fairly easy, a 1/2hp fan motor. Outside the numbers on the
plate from the factory are long gone. I found on the fan motor that it
is 1/8hp. Now the compressor.... On it is listed the voltage but not
the amps or watts but it does list the LRA (locked rotor amps) of 105.0
It is a Copeland CR38K6-PFV-370.

I found this site but even this isn't very useful to me only giving me
the RLA of 19. I read the RLA is "rated load amps" and does not mean
"Running Load Amps". RLA being the most current it should draw under
the harshest conditions.

http://www.nordyne.com/literature/8569%20Compr.pdf

None of those numbers are of much use in calculating operating costs
since none of those items runs 24x7. All those numbers will tell you is
how big a circuit the items require.

I've kept track a few times and during a hot 90F days with lows of 70F
it runs between 8 to 10 hours/day. That may be a low estimate, I'm
going to put a time meter on it for a much more accurate figure.

On Jun 26, 12:31*pm, Tony wrote:
I'm trying to figure the cost of running the central AC in my house.
Inside was fairly easy, a 1/2hp fan motor. *Outside the numbers on the
plate from the factory are long gone. *I found on the fan motor that it
is 1/8hp. *Now the compressor.... *On it is listed the voltage but not
the amps or watts but it does list the LRA (locked rotor amps) of 105.0
* It is a Copeland CR38K6-PFV-370.

I found this site but even this isn't very useful to me only giving me
the RLA of 19. *I read the RLA is "rated load amps" and does not mean
"Running Load Amps". *RLA being the most current it should draw under
the harshest conditions.

http://www.nordyne.com/literature/8569%20Compr.pdf

Time wont do it nor will ratings on the fan or compressor take into
account the controll board, other components in the condensor and how
age and condition of unit play a big part in total useage. Use a clamp
on amp meter at the circuit panel, an old fan or compressor near
failure can use alot more power, air restrictions you are unaware of
will also affect everything.

Tony wrote:

Pete C. wrote:
Tony wrote:
I'm trying to figure the cost of running the central AC in my house.
Inside was fairly easy, a 1/2hp fan motor. Outside the numbers on the
plate from the factory are long gone. I found on the fan motor that it
is 1/8hp. Now the compressor.... On it is listed the voltage but not
the amps or watts but it does list the LRA (locked rotor amps) of 105.0
It is a Copeland CR38K6-PFV-370.

I found this site but even this isn't very useful to me only giving me
the RLA of 19. I read the RLA is "rated load amps" and does not mean
"Running Load Amps". RLA being the most current it should draw under
the harshest conditions.

http://www.nordyne.com/literature/8569%20Compr.pdf

None of those numbers are of much use in calculating operating costs
since none of those items runs 24x7. All those numbers will tell you is
how big a circuit the items require.

I've kept track a few times and during a hot 90F days with lows of 70F
it runs between 8 to 10 hours/day. That may be a low estimate, I'm
going to put a time meter on it for a much more accurate figure.

Depending on the system, even a run timer may not quite get you accurate
numbers. On my HVAC the air handler has a 90 second post run after the
compressor turns off in order to increase efficiency.

In article ,
Tony wrote:

I'm trying to figure the cost of running the central AC in my house.
Inside was fairly easy, a 1/2hp fan motor. Outside the numbers on the
plate from the factory are long gone. I found on the fan motor that it
is 1/8hp. Now the compressor.... On it is listed the voltage but not
the amps or watts but it does list the LRA (locked rotor amps) of 105.0
It is a Copeland CR38K6-PFV-370.

I found this site but even this isn't very useful to me only giving me
the RLA of 19. I read the RLA is "rated load amps" and does not mean
"Running Load Amps". RLA being the most current it should draw under
the harshest conditions.

http://www.nordyne.com/literature/8569%20Compr.pdf

Now that my g.f. has a smart meter, she can go online with her iphone
and see a little graph that shows her electricity usage doubling during
my visits. But you could do that yourself with any meter. Just run the
A/C normally one week, and not at all the next. Compare results and
you've got your answer.

In article
,
Smitty Two wrote:

Now that my g.f. has a smart meter, she can go online with her iphone
and see a little graph that shows her electricity usage doubling during
my visits. But you could do that yourself with any meter. Just run the
A/C normally one week, and not at all the next. Compare results and
you've got your answer.

Depends on the weeks. This week, we had most days high 80s to mid-90s.
Next week the forecast is calling for at least 3 days with highs in the
mid 70s to low 80s. So just turning or now tells you next nothing by
itself.

--
I want to find a voracious, small-minded predator
and name it after the IRS.
Robert Bakker, paleontologist

On 6/26/2010 1:31 PM, Tony wrote:
I'm trying to figure the cost of running the central AC in my house.
Inside was fairly easy, a 1/2hp fan motor. Outside the numbers on the
plate from the factory are long gone. I found on the fan motor that it
is 1/8hp. Now the compressor.... On it is listed the voltage but not the
amps or watts but it does list the LRA (locked rotor amps) of 105.0 It
is a Copeland CR38K6-PFV-370.

I found this site but even this isn't very useful to me only giving me
the RLA of 19. I read the RLA is "rated load amps" and does not mean
"Running Load Amps". RLA being the most current it should draw under the
harshest conditions.

http://www.nordyne.com/literature/8569%20Compr.pdf
The best would be to compare the
electric meter with the unit running and
not running. This way you will have
actual watt-hours and you don't have to
think of things like power factor, etc.
But, it will change depending on
temperature. And the run time will vary
when the temperatures are cooler than
when it is just plain hot outside.

ultimately is the comfort you gain worth the larger electric bill?

"Art Todesco" wrote

http://www.nordyne.com/literature/8569%20Compr.pdf
The best would be to compare the electric meter with the unit running and
not running. This way you will have actual watt-hours and you don't have
to think of things like power factor, etc. But, it will change depending
on temperature. And the run time will vary when the temperatures are
cooler than when it is just plain hot outside.

Many electric bills give a 13 month use history. Mine even gives the
average temperature for the month. Look at months like April and October
when neither heat or AC is used much and compare to July and August and you
get a pretty good idea. Aside from that, the only accurate method is a
recording ammeter over time.

Ed Pawlowski wrote:

"Art Todesco" wrote

http://www.nordyne.com/literature/8569%20Compr.pdf
The best would be to compare the electric meter with the unit running
and not running. This way you will have actual watt-hours and you
don't have to think of things like power factor, etc. But, it will
change depending on temperature. And the run time will vary when the
temperatures are cooler than when it is just plain hot outside.

Many electric bills give a 13 month use history. Mine even gives the
average temperature for the month. Look at months like April and
October when neither heat or AC is used much and compare to July and
August and you get a pretty good idea. Aside from that, the only
accurate method is a recording ammeter over time.



I think you mean a recording watt-meter. Amps don't account for power
factor.

"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!

"cjt" wrote

I think you mean a recording watt-meter. Amps don't account for power
factor.

Correct. I was first thinking Amprobe and doing the math yourself but that
does not take time run into consideration.

A couple of years ago, I hooked up an amprobe to my 3 ton carrier unit
outside and it read 16 amps (220V).
My inside fan blower I think used 5 amps (120V).

So that's about 4,120 watts total full load. Keep in mind I usually
keep my inside fan on continuosly, and my outside unit cycles on and
off throughout the day.

On Jun 26, 11:29*pm, Mikepier wrote:
A couple of years ago, I hooked up an amprobe to my 3 ton carrier unit
outside and it read 16 amps (220V).
My inside fan blower I think used 5 amps (120V).

So that's about 4,120 watts total full load. *Keep in mind I usually
keep my *inside fan on continuosly, and my outside unit cycles on and
off throughout the day.

Find an old mechnical clock that has time and date. Those ones with
the litte flip numbers work well. Set it to 1/1/2000 midnight and
hook it into the blower circuit. At the end of a month you'll have
the number of days and hours the unit ran.

You could also buy an old meter and run a circuit through it. You'll
need a subpanel though.

Pete C. wrote:
Tony wrote:
Pete C. wrote:
Tony wrote:
I'm trying to figure the cost of running the central AC in my house.
Inside was fairly easy, a 1/2hp fan motor. Outside the numbers on the
plate from the factory are long gone. I found on the fan motor that it
is 1/8hp. Now the compressor.... On it is listed the voltage but not
the amps or watts but it does list the LRA (locked rotor amps) of 105.0
It is a Copeland CR38K6-PFV-370.

I found this site but even this isn't very useful to me only giving me
the RLA of 19. I read the RLA is "rated load amps" and does not mean
"Running Load Amps". RLA being the most current it should draw under
the harshest conditions.

http://www.nordyne.com/literature/8569%20Compr.pdf
None of those numbers are of much use in calculating operating costs
since none of those items runs 24x7. All those numbers will tell you is
how big a circuit the items require.
I've kept track a few times and during a hot 90F days with lows of 70F
it runs between 8 to 10 hours/day. That may be a low estimate, I'm
going to put a time meter on it for a much more accurate figure.

Depending on the system, even a run timer may not quite get you accurate
numbers. On my HVAC the air handler has a 90 second post run after the
compressor turns off in order to increase efficiency.

No delays here. Anyway that doesn't sound like it would increase
efficiency much, if any. I wouldn't like it blowing all that moisture
from the evaporator back into the house again as it warms up. If it's
cold when it turns off as it warms up it is still taking heat away from
what ever is around it. And if it doesn't cool off much in between
cycles, then it blows cooler air faster when it kicks on again.

Art Todesco wrote:
On 6/26/2010 1:31 PM, Tony wrote:
I'm trying to figure the cost of running the central AC in my house.
Inside was fairly easy, a 1/2hp fan motor. Outside the numbers on the
plate from the factory are long gone. I found on the fan motor that it
is 1/8hp. Now the compressor.... On it is listed the voltage but not the
amps or watts but it does list the LRA (locked rotor amps) of 105.0 It
is a Copeland CR38K6-PFV-370.

I found this site but even this isn't very useful to me only giving me
the RLA of 19. I read the RLA is "rated load amps" and does not mean
"Running Load Amps". RLA being the most current it should draw under the
harshest conditions.

http://www.nordyne.com/literature/8569%20Compr.pdf
The best would be to compare the electric meter with the unit running
and not running. This way you will have actual watt-hours and you don't
have to think of things like power factor, etc. But, it will change
depending on temperature. And the run time will vary when the
temperatures are cooler than when it is just plain hot outside.

That is very difficult with the newer digital electronic meter I have
and the way it's set up. With it on a current transformer the meter
hardly moves at all. The readings have to be multiplied by 20 for the
actual usage.

On Jun 27, 10:21*am, Chief Two Eagles wrote:
On Sat, 26 Jun 2010 13:31:37 -0400, Tony wrote:
I'm trying to figure the cost of running the central AC in my house.

Run it one month and then look at your electric bill.

I see two approaches. For the macro view, as per the above, just
comparing electric bills for summer with months in Spring or Fall with
no AC or electric heat use would give a decent approximation. My
utility bills show usage by month over the last year. I can easily
see the effects of running the AC. Of course, if you had some other
seasonal load, like pool pumps, etc, that could complicate things.

For the micro view, as someone else suggested, record the electric
meter for a time period on a day with no usage and then do the same
with the AC on.

Van Chocstraw wrote:
On Sat, 26 Jun 2010 13:31:37 -0400, Tony wrote:

I'm trying to figure the cost of running the central AC in my house.
Inside was fairly easy, a 1/2hp fan motor. Outside the numbers on the
plate from the factory are long gone. I found on the fan motor that it
is 1/8hp. Now the compressor.... On it is listed the voltage but not
the amps or watts but it does list the LRA (locked rotor amps) of 105.0
It is a Copeland CR38K6-PFV-370.

I found this site but even this isn't very useful to me only giving me
the RLA of 19. I read the RLA is "rated load amps" and does not mean
"Running Load Amps". RLA being the most current it should draw under
the harshest conditions.

http://www.nordyne.com/literature/8569%20Compr.pdf

Best method. After they read the meter start using it for a month. Next
time they read the meter, stop using it for a month until the next
reading. They usually read it the same day of the month. Take it your
self to make sure they are not estimating your bill and the reading is
actual. You could also take your own reading daily and run it one day and
not the next to get an idea of daily usage.
Using stamped values and ideal math is not accurate and won't count load,
wear, age and your comfortable temperature setting.
You can also get an amp clamp and check one leg of the supply power from
the box which will vary when the fan/ compressor cycle on/off. (Is the
inside fan on the same circuit?)

I can guess the date they read the meter give or take a day or two.
They read it from their office, no more meter man. Besides, I think I'd
die without AC for a day. Also, with my meter I could be off almost 20
kwh's a day without knowing it. My meter reading must be multiplied by
20 for actual kwh's.

wrote:
ultimately is the comfort you gain worth the larger electric bill?


I want to compare what 1 or 2 8,000 BTU window units use compared to the
central AC. I'm almost positive the window units are much more energy
efficient than the central air.

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.

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?

"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?

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.
With central units, they will do this better than room units that have to
cool a warm room. Up. Down. Up. Down.

But, then, the only way you find out is to install central, and do a post
mortem analysis.

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.

Steve

visit my blog at http://cabgbypasssurgery.com watch for the book

A fool shows his annoyance at once, but a prudent man overlooks an insult.

LouB wrote:
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?

I don't see how they can help, what kind of help would I be seeking?

Tony wrote:
LouB wrote:
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?

I don't see how they can help, what kind of help would I be seeking?

Part of their biz need is estimating electric usage. Its not going to
cost anything to ask so why not?

Also, tried google?
Here is a start:
http://www.google.com/search?sourcei...s+window+units
which got About 396,000 results (0.35 seconds)

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.

wrote:
On Jun 27, 10:21 am, Chief Two Eagles wrote:
On Sat, 26 Jun 2010 13:31:37 -0400, Tony wrote:
I'm trying to figure the cost of running the central AC in my house.
Run it one month and then look at your electric bill.

I see two approaches. For the macro view, as per the above, just
comparing electric bills for summer with months in Spring or Fall with
no AC or electric heat use would give a decent approximation. My
utility bills show usage by month over the last year. I can easily
see the effects of running the AC. Of course, if you had some other
seasonal load, like pool pumps, etc, that could complicate things.

For the micro view, as someone else suggested, record the electric
meter for a time period on a day with no usage and then do the same
with the AC on.

What I did for the zone room (this is the room where I spend 99% of my
time) stick a plain Jane window unit through the wall, make that a quiet
Plain Jane unit. Get a thermostat, relay and transformer. Wire them up
to feed the outlet serving the window unit. Set the thermostat and
forget it.

"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. You have asked a complicated
question with no answers, and are shooting down people who are answering
you. If you know all these things, just go ahead and do whatever it is you
were going to do from the get go. Unless it is new construction where you
can control the variables, you're pretty much stuck with a WYSIWYG
situation.

Steve

visit my blog at http://cabgbypasssurgery.com watch for the book

A fool shows his annoyance at once, but a prudent man overlooks an insult.

The real factors are how clean the units are, and what type of
compressor. Rotary scroll is far more efficient than an old piston
compressor.

I've seen outdoor AC unit drawing about 4.5 amps at 220 volt. (2 or
2.5 ton, can't remember). Rotary scroll compressor.

Dirty units draw a lot more power.

--
Christopher A. Young
Learn more about Jesus
www.lds.org
..


"Tony" wrote in message
...

I want to compare what 1 or 2 8,000 BTU window units use compared to
the
central AC. I'm almost positive the window units are much more energy
efficient than the central air.

FatterDumber& Happier Moe wrote:
wrote:
On Jun 27, 10:21 am, Chief Two Eagles wrote:
On Sat, 26 Jun 2010 13:31:37 -0400, Tony wrote:
I'm trying to figure the cost of running the central AC in my house.
Run it one month and then look at your electric bill.

I see two approaches. For the macro view, as per the above, just
comparing electric bills for summer with months in Spring or Fall with
no AC or electric heat use would give a decent approximation. My
utility bills show usage by month over the last year. I can easily
see the effects of running the AC. Of course, if you had some other
seasonal load, like pool pumps, etc, that could complicate things.

For the micro view, as someone else suggested, record the electric
meter for a time period on a day with no usage and then do the same
with the AC on.

What I did for the zone room (this is the room where I spend 99% of my
time) stick a plain Jane window unit through the wall, make that a quiet
Plain Jane unit. Get a thermostat, relay and transformer. Wire them up
to feed the outlet serving the window unit. Set the thermostat and
forget it.

Yes I like remote temperature controls on window units. I can't find
the one I made. It was an electric heat thermostat with the generic
snap action switch replaced with one that was the opposite as new,
meaning I don't remember if new it had a NO or NC switch, but I changed
it to be used for cooling instead of heating.

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.

and are shooting down people who are answering
you. If you know all these things, just go ahead and do whatever it is you
were going to do from the get go.

I'm trying to use the abilities I have to do a simple comparison. Using
my electric companies meter isn't very accurate as I explained. It's
presision is +/- 19Kwh.

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.







* and are shooting down people who are answering

you. *If you know all these things, just go ahead and do whatever it is you
were going to do from the get go.

I'm trying to use the abilities I have to do a simple comparison. *Using
my electric companies meter isn't very accurate as I explained. *It's
presision is +/- 19Kwh.- Hide quoted text -

- Show quoted text -

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.

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

This ain't rocket science.

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).

cjt wrote:
Ed Pawlowski wrote:

"Art Todesco" wrote

http://www.nordyne.com/literature/8569%20Compr.pdf
The best would be to compare the electric meter with the unit running
and not running. This way you will have actual watt-hours and you
don't have to think of things like power factor, etc. But, it will
change depending on temperature. And the run time will vary when the
temperatures are cooler than when it is just plain hot outside.

Many electric bills give a 13 month use history. Mine even gives the
average temperature for the month. Look at months like April and
October when neither heat or AC is used much and compare to July and
August and you get a pretty good idea. Aside from that, the only
accurate method is a recording ammeter over time.



I think you mean a recording watt-meter. Amps don't account for power
factor.

Another question maybe you can help? If I buy a clamp on type ammeter
that plugs into my DMM to display the current... if my DMM measures AC
with true RMS, will that fix the problem of the power factor?

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.

Thanks, that is what I'll be doing. Harbor Freight is about 60 miles
away so it will be a little while until I can get there again. (I was a
Harbor Freight virgin until last week. I see what people meant about
not leaving the store with only the item I intended to buy!)

Thanks again, amp clamp is the way to go.

Tony wrote:
cjt wrote:
Ed Pawlowski wrote:

"Art Todesco" wrote

http://www.nordyne.com/literature/8569%20Compr.pdf
The best would be to compare the electric meter with the unit
running and not running. This way you will have actual watt-hours
and you don't have to think of things like power factor, etc. But,
it will change depending on temperature. And the run time will vary
when the temperatures are cooler than when it is just plain hot
outside.

Many electric bills give a 13 month use history. Mine even gives the
average temperature for the month. Look at months like April and
October when neither heat or AC is used much and compare to July and
August and you get a pretty good idea. Aside from that, the only
accurate method is a recording ammeter over time.



I think you mean a recording watt-meter. Amps don't account for power
factor.

Another question maybe you can help? If I buy a clamp on type ammeter
that plugs into my DMM to display the current... if my DMM measures AC
with true RMS, will that fix the problem of the power factor?

No. Power factor arises from the phase relationship between the voltage
and current. For purely resistive loads, they are in phase and the
power factor is one. For reactive loads, they are not in phase. It's
not a question of RMS vs something else.

BTW, if you're willing to try something a bit more interesting, you can
measure total daily power use and minutes your A/C is on each day over a
period of time. Plot the two against each other and fit a line to the
data using a least-squares fit. Done correctly (including scaling
minutes to hours, making the correct choice of axes, etc.), the slope
will be A/C watts and the intercept will be your background use (i.e.
the average energy consumed by the rest of your appliances) within a
margin of error that you might even be able to quantify statistically
(although if your background use varies too dramatically or is
correlated to A/C use, the analysis might fall apart or at least become
difficult). The longer the time period you incorporate in your analysis
(within reason -- you don't want seasonal changes in efficiency, etc. to
get involved), the more accurate you can be.

:-)

cjt wrote:
Tony wrote:
cjt wrote:
Ed Pawlowski wrote:

"Art Todesco" wrote

http://www.nordyne.com/literature/8569%20Compr.pdf
The best would be to compare the electric meter with the unit
running and not running. This way you will have actual watt-hours
and you don't have to think of things like power factor, etc. But,
it will change depending on temperature. And the run time will
vary when the temperatures are cooler than when it is just plain
hot outside.

Many electric bills give a 13 month use history. Mine even gives
the average temperature for the month. Look at months like April
and October when neither heat or AC is used much and compare to July
and August and you get a pretty good idea. Aside from that, the
only accurate method is a recording ammeter over time.



I think you mean a recording watt-meter. Amps don't account for
power factor.

Another question maybe you can help? If I buy a clamp on type ammeter
that plugs into my DMM to display the current... if my DMM measures AC
with true RMS, will that fix the problem of the power factor?

No. Power factor arises from the phase relationship between the voltage
and current. For purely resistive loads, they are in phase and the
power factor is one. For reactive loads, they are not in phase. It's
not a question of RMS vs something else.

BTW, if you're willing to try something a bit more interesting, you can
measure total daily power use and minutes your A/C is on each day over a
^^^^^
make that energy ;-)

period of time. Plot the two against each other and fit a line to the
data using a least-squares fit. Done correctly (including scaling
minutes to hours, making the correct choice of axes, etc.), the slope
will be A/C watts and the intercept will be your background use (i.e.
the average energy consumed by the rest of your appliances) within a
margin of error that you might even be able to quantify statistically
(although if your background use varies too dramatically or is
correlated to A/C use,

or if the background use is too large relative to the A/C use

the analysis might fall apart or at least become
difficult). The longer the time period you incorporate in your analysis
(within reason -- you don't want seasonal changes in efficiency, etc. to
get involved), the more accurate you can be.

:-)

cjt wrote:
Tony wrote:
cjt wrote:
Ed Pawlowski wrote:

"Art Todesco" wrote

http://www.nordyne.com/literature/8569%20Compr.pdf
The best would be to compare the electric meter with the unit
running and not running. This way you will have actual watt-hours
and you don't have to think of things like power factor, etc. But,
it will change depending on temperature. And the run time will
vary when the temperatures are cooler than when it is just plain
hot outside.

Many electric bills give a 13 month use history. Mine even gives
the average temperature for the month. Look at months like April
and October when neither heat or AC is used much and compare to July
and August and you get a pretty good idea. Aside from that, the
only accurate method is a recording ammeter over time.



I think you mean a recording watt-meter. Amps don't account for
power factor.

Another question maybe you can help? If I buy a clamp on type ammeter
that plugs into my DMM to display the current... if my DMM measures AC
with true RMS, will that fix the problem of the power factor?

No. Power factor arises from the phase relationship between the voltage
and current. For purely resistive loads, they are in phase and the
power factor is one. For reactive loads, they are not in phase. It's
not a question of RMS vs something else.

BTW, if you're willing to try something a bit more interesting, you can
measure total daily power use and minutes your A/C is on each day over a
period of time. Plot the two against each other and fit a line to the
data using a least-squares fit. Done correctly (including scaling
minutes to hours, making the correct choice of axes, etc.), the slope
will be A/C watts and the intercept will be your background use (i.e.
the average energy consumed by the rest of your appliances) within a
margin of error that you might even be able to quantify statistically
(although if your background use varies too dramatically or is
correlated to A/C use, the analysis might fall apart or at least become
difficult). The longer the time period you incorporate in your analysis
(within reason -- you don't want seasonal changes in efficiency, etc. to
get involved), the more accurate you can be.

:-)


Not sure I understand all that. But if you mean to use the power
companies kwh meter, keep in mind that it only changes one kilowatt hour
for each 20 KWh used. This makes it difficult to estimate usage since
it can display the same number for hours even if I am using electric.
It wont add 1 kwh at a time, only 20 kwh at a time.