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Joe...
Posted: Mon Aug 23, 2010 9:43 pm
 
I'm in California, USA. During the summer, the wall mounted air
conditioner probably consumes around 80 to 90 percent of the electric
power used in my apartment.

This AC unit has a 220 power plug that's plugged into an outlet right next
to it.

Is there a Kill-a-Watt meter that does both 110 and 220 volts AC? I've
heard of a higher than 110 volts model obtainable in Europe, but I would
need one that works with the USA version of plug style, voltage, and AC
frequency.

Thanks.

BTW, my DMM measures the "110 Volt" AC outlets at 123 to 125 volts.

--- Joe
 
whit3rd...
Posted: Mon Aug 23, 2010 9:43 pm
 
On Aug 23, 8:43 pm, n... at (no spam) given.now (Joe) wrote:
[quote]I'm in California, USA.  During the summer, the wall mounted air
conditioner probably consumes around 80 to 90 percent of the electric
power used in my apartment.

This AC unit has a 220 power plug that's plugged into an outlet right next
to it.

Is there a Kill-a-Watt meter that does both 110 and 220 volts AC?
[/quote]
Probably not 'Kill-a-Watt' brandname, no (those are consumer-grade
and made for the lowest price possible). The meter on your house
does it, though, and lots of other power meters can do it, too.

Your AC 220V unit undoubtedly uses more current than a standard
wall socket 220V Kill-a-Watt is meant for. On the used market, the
house-power-meter gizmos go for $50 and up...
 
Martin Brown...
Posted: Tue Aug 24, 2010 1:00 am
 
On 24/08/2010 04:43, Joe wrote:
[quote]I'm in California, USA. During the summer, the wall mounted air
conditioner probably consumes around 80 to 90 percent of the electric
power used in my apartment.

This AC unit has a 220 power plug that's plugged into an outlet right next
to it.

Is there a Kill-a-Watt meter that does both 110 and 220 volts AC? I've
heard of a higher than 110 volts model obtainable in Europe, but I would
need one that works with the USA version of plug style, voltage, and AC
frequency.
[/quote]
I would hazard a guess that the inline European ones designed for 240v
would also work on a 110v supply without too much trouble (probably less
accurately and maybe needing empirical calibration).

But the other way around the US ones will be made down to a cheap and
nasty price and probably cannot safely be used at 240v. The same seems
to be true of many US wallwarts which are dedicated to 110v whereas in
almost all other countries they are commonly for 100-240v 50-60Hz.

The clip on magnetically coupled devices like OWL are probably your best
bet if the cabling will allow the sensor to be fitted. Accuracy +/-10W
is poor compared to inline ones but for A/C should not matter.

http://www.amazon.co.uk/Owl-Cm119-Wireless-Electricity-Monitor/dp/B001JJCLS0/ref=dp_cp_ob_ce_title_0

I presume smart meters are also available in the USA, but a quick web
search didn't show anything obvious.

It is probably more informative to use this type to monitor the entire
apartments usage - you can deduce the aircons consumption from how much
the thing jumps by when the compressor kicks in. You might need a pair
of magnetic sensors since ISTR US 240 is across antiphase 110v supply.

Regards,
Martin Brown
 
PeterD...
Posted: Tue Aug 24, 2010 5:59 am
 
On Mon, 23 Aug 2010 20:43:44 -0700, none at (no spam) given.now (Joe) wrote:

[quote]...

BTW, my DMM measures the "110 Volt" AC outlets at 123 to 125 volts.

--- Joe
[/quote]
There is no such thing as a 110 volt outlet in the US. The standard is
120 volts, so if it reads 123 to 125 you are getting very close to the
desired or specified voltage(s).
 
mike...
Posted: Tue Aug 24, 2010 6:26 am
 
Joe wrote:
[quote]I'm in California, USA. During the summer, the wall mounted air
conditioner probably consumes around 80 to 90 percent of the electric
power used in my apartment.

This AC unit has a 220 power plug that's plugged into an outlet right next
to it.

Is there a Kill-a-Watt meter that does both 110 and 220 volts AC? I've
heard of a higher than 110 volts model obtainable in Europe, but I would
need one that works with the USA version of plug style, voltage, and AC
frequency.

Thanks.

BTW, my DMM measures the "110 Volt" AC outlets at 123 to 125 volts.

--- Joe
[/quote]
Mike's metrology question:
What are you gonna do with the information when you get it?

You save money by turning up the thermostat or turning it off.
You don't need any power measurements to do that.

The utility company has a meter on your dwelling. You can read
the numbers and get gross answers. By timing how fast the wheel
(real or simulated on an LCD) goes around, you can get short-term
numbers. The scale factor is written on the meter face although
cryptically.

Put the house in stable power drain.
Time the wheel.
Run the air conditioner full on.
Time the wheel.
Turn off the compressor, leave the fan on.
Time the wheel.
Turn the air conditioner off.
Time the wheel.
If the first reading isn't the same as the last one,
something turned on/off that you didn't expect. Repeat
the process till both numbers are the same.

One thing that surprised me is that the fan consumes
an appreciable percentage of the total power...and it usually
runs all the time on a window unit.
You know the fan consumption from the measurements above times
the time the unit is on.
Pay attention to how often the compressor runs to get the
other part of the consumption.

Now what?
You can either turn it off or turn up the thermostat.
And you already knew that.

In my case, the 20" box fan that I use to vent the house in the
evenings takes about 15% of the energy used to run the central air.
So, if the air conditioner runs less than 15% of the time at night,
it's cheaper to leave it on than to run the box fan all night.
That's critically dependent on your insulation.
Moving air is expensive, even if you don't try to modify its temperature.

If you have an electric water heater, that can consume significant energy.
Typically, there's nowhere to hook up a kill-a-watt to that.
But timing the meter wheel still works.
And you don't have to worry about power factor. The wheel tells you
EXACTLY what the utility is billing you for.

Bottom line is that you already have the means to make the measurement
for free.

Having a cool toy that continuously reads consumption is fun
until the new-car-smell wears off, but the payback period
for the purchase can be LONG.
I paid $2 for my KAW at a garage sale. Don't expect to save
an extra $2 because I have it. I already had a stopwatch.
 
krw at (no spam) att.bizzzzzzzzzzzz...
Posted: Tue Aug 24, 2010 4:59 pm
 
On Tue, 24 Aug 2010 08:00:01 +0100, Martin Brown
<|||newspam||| at (no spam) nezumi.demon.co.uk> wrote:

[quote]On 24/08/2010 04:43, Joe wrote:
I'm in California, USA. During the summer, the wall mounted air
conditioner probably consumes around 80 to 90 percent of the electric
power used in my apartment.

This AC unit has a 220 power plug that's plugged into an outlet right next
to it.

Is there a Kill-a-Watt meter that does both 110 and 220 volts AC? I've
heard of a higher than 110 volts model obtainable in Europe, but I would
need one that works with the USA version of plug style, voltage, and AC
frequency.

I would hazard a guess that the inline European ones designed for 240v
would also work on a 110v supply without too much trouble (probably less
accurately and maybe needing empirical calibration).

But the other way around the US ones will be made down to a cheap and
nasty price and probably cannot safely be used at 240v. The same seems
to be true of many US wallwarts which are dedicated to 110v whereas in
almost all other countries they are commonly for 100-240v 50-60Hz.
[/quote]
Kill-A-Watts monitor the neutral current (keeps the innards at a low voltage),
so are useless, as is, for standard US 240V split-phase. A friend hacked one
to monitor the hot current and it worked just fine on a 240V circuit. Safe?
Well, it was hacked. ;-)

[quote]The clip on magnetically coupled devices like OWL are probably your best
bet if the cabling will allow the sensor to be fitted. Accuracy +/-10W
is poor compared to inline ones but for A/C should not matter.

http://www.amazon.co.uk/Owl-Cm119-Wireless-Electricity-Monitor/dp/B001JJCLS0/ref=dp_cp_ob_ce_title_0

I presume smart meters are also available in the USA, but a quick web
search didn't show anything obvious.

It is probably more informative to use this type to monitor the entire
apartments usage - you can deduce the aircons consumption from how much
the thing jumps by when the compressor kicks in. You might need a pair
of magnetic sensors since ISTR US 240 is across antiphase 110v supply.

Regards,
Martin Brown[/quote]
 
Hammy...
Posted: Tue Aug 24, 2010 5:13 pm
 
"krw at (no spam) att.bizzzzzzzzzzzz" <krw at (no spam) att.bizzzzzzzzzzzz> wrote in
news:1hj876pemimpn1m95ucdqddg4run7qmnm5 at (no spam) 4ax.com:

[quote]Kill-A-Watts monitor the neutral current (keeps the innards at a low
voltage), so are useless, as is, for standard US 240V split-phase. A
friend hacked one to monitor the hot current and it worked just fine
on a 240V circuit. Safe? Well, it was hacked. ;-)

I just used mine on a 300W boost PFC and according to the kill a watt my[/quote]
boost converter is makeing power. For a measured 130W out the Kill a watt
says my boost is only drawing 115W at (no spam) 0.97 PF.

I have seen it get closer on other SMPS's but its off here!
 
Cydrome Leader...
Posted: Wed Aug 25, 2010 6:29 am
 
In sci.electronics.design PeterD <peter2 at (no spam) hipson.net> wrote:
[quote]On Mon, 23 Aug 2010 20:43:44 -0700, none at (no spam) given.now (Joe) wrote:

...

BTW, my DMM measures the "110 Volt" AC outlets at 123 to 125 volts.

--- Joe

There is no such thing as a 110 volt outlet in the US. The standard is
120 volts, so if it reads 123 to 125 you are getting very close to the
desired or specified voltage(s).
[/quote]
It used to be 110, decades ago and has crept up to a nominal 120.

check any old appliance with a cloth and rubber cord. they'll be maked
110, 115 and even 117 volts and maybe even 60 "cycles".
 
Joe...
Posted: Wed Aug 25, 2010 11:51 am
 
In article <i50drc$fhj$1 at (no spam) news.eternal-september.org>, spamme0 at (no spam) go.com wrote:

[quote]Joe wrote:
I'm in California, USA. During the summer, the wall mounted air
conditioner probably consumes around 80 to 90 percent of the electric
power used in my apartment.

This AC unit has a 220 power plug that's plugged into an outlet right next
to it.

Is there a Kill-a-Watt meter that does both 110 and 220 volts AC? I've
heard of a higher than 110 volts model obtainable in Europe, but I would
need one that works with the USA version of plug style, voltage, and AC
frequency.

Thanks.

BTW, my DMM measures the "110 Volt" AC outlets at 123 to 125 volts.

--- Joe

Mike's metrology question:
What are you gonna do with the information when you get it?
[/quote]

A compare and contrast of the costs of various ways to keep comfortable on
hot days.


[quote]
You save money by turning up the thermostat or turning it off.
You don't need any power measurements to do that.
[/quote]

And you don't need to be condescending.


[quote]
The utility company has a meter on your dwelling.
[/quote]

<snip lots of stuff about watching the meter>


I did mention "my apartment". I don't have access to my meter.


[quote]One thing that surprised me is that the fan consumes
an appreciable percentage of the total power...and it usually
runs all the time on a window unit.
You know the fan consumption from the measurements above times
the time the unit is on.
Pay attention to how often the compressor runs to get the
other part of the consumption.
[/quote]

See? Compare and contrast.


[quote]Now what?
You can either turn it off or turn up the thermostat.
And you already knew that.
[/quote]
There you go again with the condescension.

[quote]In my case, the 20" box fan that I use to vent the house in the
evenings takes about 15% of the energy used to run the central air.
So, if the air conditioner runs less than 15% of the time at night,
it's cheaper to leave it on than to run the box fan all night.
That's critically dependent on your insulation.
Moving air is expensive, even if you don't try to modify its temperature.

[/quote]
Interesting. That's the kind of stuff I'd like to measure, too.



[quote]Bottom line is that you already have the means to make the measurement
for free.
[/quote]
Nope.

[quote]
Having a cool toy that continuously reads consumption is fun
until the new-car-smell wears off, but the payback period
for the purchase can be LONG.
I paid $2 for my KAW at a garage sale. Don't expect to save
an extra $2 because I have it. I already had a stopwatch.
[/quote]
Who said I want to measure the wattage use ONLY of the A/C? I did mention
that I would like it for 110-220 V.

Anyways, thanks for the effort. There is some useful info there.

--- Joe
 
Martin Brown...
Posted: Wed Aug 25, 2010 1:17 pm
 
On 25/08/2010 18:51, Joe wrote:
[quote]In article<i50drc$fhj$1 at (no spam) news.eternal-september.org>, spamme0 at (no spam) go.com wrote:

Joe wrote:
I'm in California, USA. During the summer, the wall mounted air
conditioner probably consumes around 80 to 90 percent of the electric
power used in my apartment.

This AC unit has a 220 power plug that's plugged into an outlet right next
to it.

Is there a Kill-a-Watt meter that does both 110 and 220 volts AC? I've
heard of a higher than 110 volts model obtainable in Europe, but I would
need one that works with the USA version of plug style, voltage, and AC
frequency.

Thanks.

BTW, my DMM measures the "110 Volt" AC outlets at 123 to 125 volts.

--- Joe

Mike's metrology question:
What are you gonna do with the information when you get it?

A compare and contrast of the costs of various ways to keep comfortable on
hot days.


You save money by turning up the thermostat or turning it off.
You don't need any power measurements to do that.

And you don't need to be condescending.
[/quote]
But he is basically correct. The big cost is incurred maintaining a huge
temperature differential.

Raising the internal temperature to be closer to the external one is
actually more comfortable too. I have lost count of the number of US
premises where in summer conference rooms are kept so cold that you need
to put on a sweater or jacket to survive. In winter the situation is
reversed with everywhere kept soporiphically warm and stuffy.

[quote]The utility company has a meter on your dwelling.
[/quote]
Which they struggle to read correctly. Mine is prehistoric with
alternate dials with opposite handedness and in a most awkward corner.
[quote]
snip lots of stuff about watching the meter

I did mention "my apartment". I don't have access to my meter.
[/quote]
However, if you can clip a magnetic sensor onto the mains inlets then
you can measure total power delivered (and most of it will be going to
the aircon and/or and electric cooker or space heaters).
[quote]

One thing that surprised me is that the fan consumes
an appreciable percentage of the total power...and it usually
runs all the time on a window unit.
You know the fan consumption from the measurements above times
the time the unit is on.
Pay attention to how often the compressor runs to get the
other part of the consumption.


See? Compare and contrast.


Now what?
You can either turn it off or turn up the thermostat.
And you already knew that.

There you go again with the condescension.

In my case, the 20" box fan that I use to vent the house in the
evenings takes about 15% of the energy used to run the central air.
So, if the air conditioner runs less than 15% of the time at night,
it's cheaper to leave it on than to run the box fan all night.
That's critically dependent on your insulation.
Moving air is expensive, even if you don't try to modify its temperature.

Interesting. That's the kind of stuff I'd like to measure, too.
[/quote]
A realtime display in your living space makes you aware when something
has been left on. The one we fitted to our village hall has saved a
fortune by preventing the main hot water immersion heater being left on
when people leave.

Regards,
Martin Brown
 
Eeyore...
Posted: Wed Aug 25, 2010 4:51 pm
 
Hammy wrote:
[quote]"krw at (no spam) att.bizzzzzzzzzzzz" <krw at (no spam) att.bizzzzzzzzzzzz> wrote

Kill-A-Watts monitor the neutral current (keeps the innards at a low
voltage), so are useless, as is, for standard US 240V split-phase. A
friend hacked one to monitor the hot current and it worked just fine
on a 240V circuit. Safe? Well, it was hacked. ;-)

I just used mine on a 300W boost PFC and according to the kill a watt my
boost converter is makeing power. For a measured 130W out the Kill a watt
says my boost is only drawing 115W at (no spam) 0.97 PF.

I have seen it get closer on other SMPS's but its off here!
[/quote]
There are some really cheap and nasty meters of this type that are
hopelessly inaccurate. I suspect you have one.

Graham
 
Eeyore...
Posted: Wed Aug 25, 2010 4:57 pm
 
whit3rd wrote:
[quote]On Aug 23, 8:43 pm, n... at (no spam) given.now (Joe) wrote:
I'm in California, USA. During the summer, the wall mounted air
conditioner probably consumes around 80 to 90 percent of the electric
power used in my apartment.

This AC unit has a 220 power plug that's plugged into an outlet right next
to it.

Is there a Kill-a-Watt meter that does both 110 and 220 volts AC?

Probably not 'Kill-a-Watt' brandname, no (those are consumer-grade
and made for the lowest price possible). The meter on your house
does it, though, and lots of other power meters can do it, too.

Your AC 220V unit undoubtedly uses more current than a standard
wall socket 220V Kill-a-Watt is meant for. On the used market, the
house-power-meter gizmos go for $50 and up...
[/quote]
230V 'Kill a Watts' are rated at up to 16A ( approx 3.5 kW ) as this is
the most popular European wall socket.

I use an Efergy brand unit ( UK model ).
http://www.efergy.com/pages/Energy-Monitor-Socket/pgid-20592.aspx

Graham
 
Eeyore...
Posted: Wed Aug 25, 2010 5:04 pm
 
Cydrome Leader wrote:
[quote]In sci.electronics.design PeterD <peter2 at (no spam) hipson.net> wrote:
On Mon, 23 Aug 2010 20:43:44 -0700, none at (no spam) given.now (Joe) wrote:

...

BTW, my DMM measures the "110 Volt" AC outlets at 123 to 125 volts.

--- Joe
There is no such thing as a 110 volt outlet in the US. The standard is
120 volts, so if it reads 123 to 125 you are getting very close to the
desired or specified voltage(s).

It used to be 110, decades ago and has crept up to a nominal 120.

check any old appliance with a cloth and rubber cord. they'll be maked
110, 115 and even 117 volts and maybe even 60 "cycles".
[/quote]
The previous poster is correct. The US standard wall socket voltage has
been 120V for many decades. Read the published standards.

Graham
 
Daniel Mandic...
Posted: Thu Aug 26, 2010 2:00 am
 
Cydrome Leader wrote:

[quote]It used to be 110, decades ago and has crept up to a nominal 120.

check any old appliance with a cloth and rubber cord. they'll be
maked 110, 115 and even 117 volts and maybe even 60 "cycles".
[/quote]
Hi!


I thought it is 115V in America today....

Old appliances in europe had 220-240V (written on a backside-badge)
input. The former 220V standard has been raised to 230V today.

Bad designed circuitry, awaiting exactly 110 or 220V, might have a
heat-problem.... that's all, but can destroy a device in long term
though.


--
Daniel Mandic
 
Nobody...
Posted: Thu Aug 26, 2010 3:26 am
 
On Thu, 26 Aug 2010 08:00:45 +0000, Daniel Mandic wrote:

[quote]Old appliances in europe had 220-240V (written on a backside-badge)
input. The former 220V standard has been raised to 230V today.
[/quote]
Or lowered to 230V for the UK and Eire, where it used to be 240V. For now,
anything sold in the EU must work with 230V +/- 10% (207V-253V).

[quote]Bad designed circuitry, awaiting exactly 110 or 220V, might have a
heat-problem.... that's all, but can destroy a device in long term
though.
[/quote]
It's a problem for incandescent light bulbs, which need to run close to
the filament's limit for maximum efficiency. A bulb designed for 240V will
produce signficiantly less light at 220V, while a bulb designed for 220V
will burn out rather quickly at 240V.
 
 
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