Kill-a-Watt surprises

[William Sommerwerck]

Its been pointed that you don't really need a watt or watt-hour meter to
save money -- you just turn off things you're not using.

This is not altogether true.

My electric bill was ridiculous, so I started checking. I'd been too lazy to
regularly turn off my A/V system's equipment, which includes a number of
vampire devices.

I was surprised to discover that the Parasound controller pulled 30VA, even
when not turned on. And a Lexicon CP-3plus drew 20VA, simply in standby. As
I rarely use it, I turned the standby switch to "off".

Most of the vampire devices are items I don't use regularly. I'm going to
move them to their own strip, so that they will always be off, except when
actually being used.

------
"We already know the answers -- we just haven't asked the right
questions." -- Edwin Land

 

[AZ Nomad]

On Mon, 2 Nov 2009 09:00:58 -0800, William Sommerwerck <grizzledgeezer@comcast.net> wrote:

Its been pointed that you don't really need a watt or watt-hour meter to
save money -- you just turn off things you're not using.

This is not altogether true.

My electric bill was ridiculous, so I started checking. I'd been too lazy to
regularly turn off my A/V system's equipment, which includes a number of
vampire devices.

I was surprised to discover that the Parasound controller pulled 30VA, even
when not turned on. And a Lexicon CP-3plus drew 20VA, simply in standby. As
I rarely use it, I turned the standby switch to "off".

Most of the vampire devices are items I don't use regularly. I'm going to
move them to their own strip, so that they will always be off, except when
actually being used.

You can get an idea just from the temperature of the device when it is
on standby. Cold devices can be ignored. I've found the worst
offender in all my AV equipment is the cable box.

 

[William Sommerwerck]

Most of the vampire devices are items I don't use regularly.
I'm going to move them to their own strip, so that they will
always be off, except when actually being used.

You can get an idea just from the temperature of the device when
it is on standby. Cold devices can be ignored. I've found the worst
offender in all my AV equipment is the cable box.

The Parasound was always slightly warm, despite its size, so the power it
pulled was not surprising. But a unit with a "compact" power supply might be
warmer -- in that area -- than a unit that pulls more power, but whose
supply uses a bigger transformer or is further from the cabinet's cover.

 

[Jeff Liebermann]

On Mon, 2 Nov 2009 09:00:58 -0800, "William Sommerwerck"
<grizzledgeezer@comcast.net> wrote:

Its been pointed that you don't really need a watt or watt-hour meter to
save money -- you just turn off things you're not using.

One measurement is worth many guesses. I have 3 kill-a-watt meters.
Very handy.

This is not altogether true.

If it's not all together true, then it must be all apart false.

My electric bill was ridiculous, so I started checking. I'd been too lazy to
regularly turn off my A/V system's equipment, which includes a number of
vampire devices.

Halloween was Saturday, so I'm not surprised that you're still seeing
vampires.

I was surprised to discover that the Parasound controller pulled 30VA, even
when not turned on. And a Lexicon CP-3plus drew 20VA, simply in standby. As
I rarely use it, I turned the standby switch to "off".

Your electric meter measures watts, not VA. If you know the power
factor, you can convert these VA measurements to watts and eventually
to your cost of electricity. The kill-a-watt meter shows both VA and
watts (as well as PF).

Most of the vampire devices are items I don't use regularly. I'm going to
move them to their own strip, so that they will always be off, except when
actually being used.

It's the ones that are left on 24x7x365 that will get you. Borrowed
from one of my previous rants on the subject:

My DirecTV R15-500 DVR burns:
Operating power: 22 watts or 42 VA
Standby power: 21 watts or 40 VA
That's only 8 cents per day or $29/year (at $0.15/kw-hr). Much
better. However, the 0.5 power factor isn't very impressive but it's
under 75w so it doesn't have to comply with EN61000-3-2.

Using the revised numbers, yields:
12.5 watts for the 120GB Seagate hard disk
<http://www.seagate.com/docs/pdf/datasheet/disc/ds_barracuda_7200_9.pdf>
3.5 watts for my single LNB
Subtracting from the 22.0 watts total leaves:
6.0 watts for everything else including switcher efficiency.
I don't think there's room for much improvement (except for power
factor correction).


--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[AZ Nomad]

On Mon, 2 Nov 2009 10:06:26 -0800, William Sommerwerck <grizzledgeezer@comcast.net> wrote:

Most of the vampire devices are items I don't use regularly.
I'm going to move them to their own strip, so that they will
always be off, except when actually being used.

You can get an idea just from the temperature of the device when
it is on standby. Cold devices can be ignored. I've found the worst
offender in all my AV equipment is the cable box.

The Parasound was always slightly warm, despite its size, so the power it
pulled was not surprising. But a unit with a "compact" power supply might be
warmer -- in that area -- than a unit that pulls more power, but whose
supply uses a bigger transformer or is further from the cabinet's cover.

A device that pulls a lot of power won't just have a hot transformer.
It'll have a number of VLSI chips all gettng rather warm heating the
entire cabinet. The difference between a component pulling 5W and
one pulling 60W isn't subtle.

 

[UCLAN]

William Sommerwerck wrote:

Its been pointed that you don't really need a watt or watt-hour meter to
save money -- you just turn off things you're not using.

This is not altogether true.

My electric bill was ridiculous, so I started checking. I'd been too lazy to
regularly turn off my A/V system's equipment, which includes a number of
vampire devices.

I was surprised to discover that the Parasound controller pulled 30VA, even
when not turned on. And a Lexicon CP-3plus drew 20VA, simply in standby. As
I rarely use it, I turned the standby switch to "off".

Most of the vampire devices are items I don't use regularly. I'm going to
move them to their own strip, so that they will always be off, except when
actually being used.

Or use a strip with separate ON/OFF switches for each outlet.

http://www.amazon.com/gp/product/B0006HBBF0/ref=pd_lpo_k2_dp_sr_1?pf_rd_p=486539851&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B0002GL50Q&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=0688EK2C3B3PRAAMCN2Y

http://tinyurl.com/ybzqx2a

 

[D Yuniskis]

William Sommerwerck wrote:

Its been pointed that you don't really need a watt or watt-hour meter to
save money -- you just turn off things you're not using.

This is not altogether true.

No, its true. You just tend to erroneously dismiss things that
you *think* you aren't using -- but really *are*!

My electric bill was ridiculous, so I started checking. I'd been too lazy to
regularly turn off my A/V system's equipment, which includes a number of
vampire devices.

I was surprised to discover that the Parasound controller pulled 30VA, even
when not turned on. And a Lexicon CP-3plus drew 20VA, simply in standby. As
I rarely use it, I turned the standby switch to "off".

Most of the vampire devices are items I don't use regularly. I'm going to
move them to their own strip, so that they will always be off, except when
actually being used.

I've taken to installing power switches in all of the devices
that don't have them. They all *claim* to "sleep" but even
sleeping they often are wasteful.

My current worst offender is the 100Mbps switch. Sure, I can
turn it off -- as long as nothing will have to talk to anything
else! :< (this will be problematic when I switch to VoIP phones;
I guess I'll have to install a low power 10Mbps switch/hub just
for those loads)

 

[William Sommerwerck]

Your electric meter measures watts, not VA. If you know the power
factor, you can convert these VA measurements to watts and eventually
to your cost of electricity. The kill-a-watt meter shows both VA and
watts (as well as PF).

My understanding was that the watt-hour meter actually measure VA-hours. I
asked the electric company once, and that said that was the case. But I
wasn't speaking with an engineer.

 

[Jeff Liebermann]

On Mon, 2 Nov 2009 14:13:27 -0800, "William Sommerwerck"
<grizzledgeezer@comcast.net> wrote:

Your electric meter measures watts, not VA. If you know the power
factor, you can convert these VA measurements to watts and eventually
to your cost of electricity. The kill-a-watt meter shows both VA and
watts (as well as PF).

My understanding was that the watt-hour meter actually measure VA-hours. I
asked the electric company once, and that said that was the case. But I
wasn't speaking with an engineer.

I beg to differ. If it measured volt-amps, it would say volt-amps,
not watts.

See:
<http://en.wikipedia.org/wiki/Electricity_meter>
"Demand is normally measured in watts..."
and:
"Modern electricity meters operate by continuously measuring the
instantaneous voltage (volts) and current (amperes) and finding the
product of these to give instantaneous electrical power (watts) which
is then integrated against time to give energy used (joules,
kilowatt-hours etc)."

<http://www.generatorguide.net/watt-acpower.html>
"Note that residential meters only measure only real power (watts) and
PF of your appliances do not affect your cost of electricity".

Note that some utilities charge extra for low power factor loads:
<http://www.envido.co.uk/what-we-do/power-factor-correction>

Marginally related but interesting drivel:
<http://www.google.org/powermeter/>

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[TonyS]

William Sommerwerck wrote:

I was surprised to discover that the Parasound controller pulled 30VA, even
when not turned on. And a Lexicon CP-3plus drew 20VA, simply in standby. As
I rarely use it, I turned the standby switch to "off".

Same here. I checked all my devices for standby power and found that the LCD TV
(Pavo) drew a ridiculous 55VA in standby. The other devices weren't exactly
power savers either.

I found that my Yamaha surround sound amp has only a few Watts standby power and
also has a switched AC mains output socket, which unfortunately can only handle
100 or so VA.

I built a relay box controlled by the amp's switched mains output and controls a
power board in which all the "bad" devices are plugged in. Now I can switch the
whole "entertainment" corner (except PVR) on and off with the amp's remote control.
Since the TV forgets its setup when switched off the universal remote has to go
through a 1 minute setup procedure though. That'll deplete the batteries early
..... :-(

Tony

 

[D Yuniskis]

Jeff Liebermann wrote:

My DirecTV R15-500 DVR burns:
Operating power: 22 watts or 42 VA
Standby power: 21 watts or 40 VA
That's only 8 cents per day or $29/year (at $0.15/kw-hr). Much
better. However, the 0.5 power factor isn't very impressive but it's
under 75w so it doesn't have to comply with EN61000-3-2.

Using the revised numbers, yields:
12.5 watts for the 120GB Seagate hard disk
http://www.seagate.com/docs/pdf/datasheet/disc/ds_barracuda_7200_9.pdf
3.5 watts for my single LNB
Subtracting from the 22.0 watts total leaves:
6.0 watts for everything else including switcher efficiency.
I don't think there's room for much improvement (except for power
factor correction).

Spin the disk down when it isn;t being used! I.e., the device
knows when it needs to turn itself on to *record* a show. So,
it can conceivably spin down the drive when it knows it does
NOT need to record anything! (it can spin the drive up 6 seconds
before air-time and thus ensure that nothing is "missed").

Likewise, it can see when you are *using* itself to play back
video so it could safely spin down the drive at other times
(and force you to incur that 3 or 4 second spin-up delay
when you *do* grab the remote and start poking at it)

Done properly, even that 6W figure could turn into 1/2W as
the entire device could sleep when not in use -- and just
wake-up when the next "alarm time" is scheduled *or* when
IR is sensed from the remote.

 

[Jeff Liebermann]

On Mon, 02 Nov 2009 20:18:50 -0700, D Yuniskis
<not.going.to.be@seen.com> wrote:

Spin the disk down when it isn;t being used!

Sure, but I don't have any control over the DirecTV firmware. What I
have is what I have to live with. My guess(tm) is that they spin the
disk continuously to improve the operating life of the hard disk
drive. I have servers that run 24x7x365 that never seem to eat a disk
drive. I have one in the office that's been running continuously
since about 1995. However, the same drives, will die after 3-5 years
with start-stop operation.

Done properly, even that 6W figure could turn into 1/2W as
the entire device could sleep when not in use -- and just
wake-up when the next "alarm time" is scheduled *or* when
IR is sensed from the remote.

Well, it's not quite so simple. The box downloads firmware updates
and program listings erratically. It also calls home on the phone
line in the middle of the night for pay per view and quality control.
I can also make record schedule entries via the internet. If the LNB
is powered down, it takes about a minute for things to settle down and
stabilize again. Power consumption can probably be drastically
reduced using some manner of standby mode, but my box is VERY busy,
which means the algorithm may be rather complex and the savings rather
limited. If it costs me about $3/month to avoid complications and
extend the life of the hard disk, I would probably pay the price.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

 

[N_Cook]

AZ Nomad <aznomad.3@PremoveOBthisOX.COM> wrote in message
news:slrnheu4qt.i6f.aznomad.3@ip70-176-155-130.ph.ph.cox.net...

On Mon, 2 Nov 2009 09:00:58 -0800, William Sommerwerck
grizzledgeezer@comcast.net> wrote:
Its been pointed that you don't really need a watt or watt-hour meter to
save money -- you just turn off things you're not using.

This is not altogether true.

My electric bill was ridiculous, so I started checking. I'd been too lazy
to
regularly turn off my A/V system's equipment, which includes a number of
vampire devices.

I was surprised to discover that the Parasound controller pulled 30VA,
even
when not turned on. And a Lexicon CP-3plus drew 20VA, simply in standby.
As
I rarely use it, I turned the standby switch to "off".

Most of the vampire devices are items I don't use regularly. I'm going to
move them to their own strip, so that they will always be off, except
when
actually being used.

You can get an idea just from the temperature of the device when it is
on standby. Cold devices can be ignored. I've found the worst
offender in all my AV equipment is the cable box.

I bought a set-top box (UK Freeview) and thought to myself
"hang on a bit the box is as warm with green LED on as on red standby"
I measured consumed watts in both states and standby is 80 percent of the on
state. I put in a hard on/off switch , data held in EEProm or whatever and
no difference in function except programme info pages takes a couple of
minutes to gather


--
Diverse Devices, Southampton, England
electronic hints and repair briefs , schematics/manuals list on
http://home.graffiti.net/diverse:graffiti.net/

 

[D Yuniskis]

Jeff Liebermann wrote:

On Mon, 02 Nov 2009 20:18:50 -0700, D Yuniskis
not.going.to.be@seen.com> wrote:

Spin the disk down when it isn;t being used!

Sure, but I don't have any control over the DirecTV firmware. What I

Of course! My point was that *they* could still make significant
savings in their dessign.

have is what I have to live with. My guess(tm) is that they spin the
disk continuously to improve the operating life of the hard disk
drive. I have servers that run 24x7x365 that never seem to eat a disk

Spin the drives down and then try spinning them back up! :>
(i.e., the stress seems to be on the spin-up)

I think modern drives have really long MTBFs. What kills
disks is the same thing that kills most electronic things: heat.

drive. I have one in the office that's been running continuously
since about 1995. However, the same drives, will die after 3-5 years
with start-stop operation.

I haven't lost a disk in 30 years (touch wood). The drives in my
primary machine have date stamps of 2002. They see a fair bit
of power cycling (since the machine doesn't have a reset button,
the only way to truly reset it is to cycle power and wait for
all the drives to spin up again).

Done properly, even that 6W figure could turn into 1/2W as
the entire device could sleep when not in use -- and just
wake-up when the next "alarm time" is scheduled *or* when
IR is sensed from the remote.

Well, it's not quite so simple. The box downloads firmware updates
and program listings erratically. It also calls home on the phone
line in the middle of the night for pay per view and quality control.

These aren't random events. There is software inside the
box *deciding* when to do these things. So, it could
go to sleep and still have told something to wake it up
at its next scheduled activity.

I can also make record schedule entries via the internet. If the LNB
is powered down, it takes about a minute for things to settle down and
stabilize again. Power consumption can probably be drastically
reduced using some manner of standby mode, but my box is VERY busy,
which means the algorithm may be rather complex and the savings rather

Modern processors have very complex power management features
*in* the processor (SMI). If they aren't being exploited,
it is because the box's manufacturer was just lazy (and had
no incentive to do so!)

limited. If it costs me about $3/month to avoid complications and
extend the life of the hard disk, I would probably pay the price.

I've been moving all of my "software" (movies, music) onto
large disks (several TB) so that I can serve this from a
single machine. I let the drives power down when not in use.
My biggest problem is the network switch that I rely on
for distribution as it can't be powered down.

 

[D Yuniskis]

William Sommerwerck wrote:

Your electric meter measures watts, not VA. If you know the power
factor, you can convert these VA measurements to watts and eventually
to your cost of electricity. The kill-a-watt meter shows both VA and
watts (as well as PF).

My understanding was that the watt-hour meter actually measure VA-hours. I
asked the electric company once, and that said that was the case. But I
wasn't speaking with an engineer.

No -- with caveats.

The vast majority of KWHr meters (in the US) are old "motors".
These are tuned electromechanical kludges that are absolutely
amazing in that they work AT ALL! :> And, that they are so
easily mass produced and have such long service lives!

The are typically calibrated at 10% load and 100% load.
And, again, at 50% (lagging) power factor (e.g., 60 degrees).

I *think* that the nature of most loads is such that
they can still claim their 1% accuracy despite all the
perverse loads that have come into being since they
were created (decades ago).

Many electronic KWHr meters are motors outfitted with
mechanisms to "count revolutions". This allows the
"new technology" to benefit from all fo the design
tweeks that the meters have experienced in their history.

It is possible to convert a KWHr meter to a VARHOUR meter
(an RC network in one of the coils, IIRC).

Some newer "solid state" meters can produce a variety of
metrics (VAR, KW, ToU, Q, etc.) as they typically have
access to more data than a regular "motor" would.

I've often wondered how far you can push an old "motor"
in terms of distorting the load. E.g., how would a 120Hz
*impulse* load be registered? But, its just an intellectual
exercise as coming up with a way to make *use* of power
"extracted" in this form would be problematic.

 

[David]

"William Sommerwerck" <grizzledgeezer@comcast.net> wrote in
message news:hcn3ak$4fj$1@news.eternal-september.org...

Its been pointed that you don't really need a watt or
watt-hour meter to
save money -- you just turn off things you're not using.

This is not altogether true.

My electric bill was ridiculous, so I started checking.
I'd been too lazy to
regularly turn off my A/V system's equipment, which
includes a number of
vampire devices.

I was surprised to discover that the Parasound controller
pulled 30VA, even
when not turned on. And a Lexicon CP-3plus drew 20VA,
simply in standby. As
I rarely use it, I turned the standby switch to "off".

Most of the vampire devices are items I don't use
regularly. I'm going to
move them to their own strip, so that they will always be
off, except when
actually being used.

I have just two comments on this:

1) If you are a residence, you are metered and billed by
watts (re: real power) rather than volt*amps. Measure the
watts to see the power consumption that actually is part of
your billing.
2) If you live in an area that requires heating your house
for a majority of a year, the power dissipated is added to
the heating of your house during the heating season and
reduces energy consumption from the furnace energy supplier.
The power is not wasted in this situation. This fact is
rarely considered by the media.

David

 

[Phil Hobbs]

William Sommerwerck wrote:

Your electric meter measures watts, not VA. If you know the power
factor, you can convert these VA measurements to watts and eventually
to your cost of electricity. The kill-a-watt meter shows both VA and
watts (as well as PF).

My understanding was that the watt-hour meter actually measure VA-hours. I
asked the electric company once, and that said that was the case. But I
wasn't speaking with an engineer.


That's VARs, not VA-hours. For 'volt-ampere reactive'.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net

 

[William Sommerwerck]

My understanding was that the watt-hour meter actually measure VA-hours.
I
asked the electric company once, and that said that was the case. But I
wasn't speaking with an engineer.

That's VARs, not VA-hours. For 'volt-ampere reactive'.

If you can have watt-hours, you can have VA-hours. Both are units of energy.

Is VAR a unit of energy? No, it's a unit of (reactive) power. Energy and
power are not the same.

 

[Van Chocstraw]

William Sommerwerck wrote:

Its been pointed that you don't really need a watt or watt-hour meter to
save money -- you just turn off things you're not using.

This is not altogether true.

My electric bill was ridiculous, so I started checking. I'd been too lazy to
regularly turn off my A/V system's equipment, which includes a number of
vampire devices.

I was surprised to discover that the Parasound controller pulled 30VA, even
when not turned on. And a Lexicon CP-3plus drew 20VA, simply in standby. As
I rarely use it, I turned the standby switch to "off".

Most of the vampire devices are items I don't use regularly. I'm going to
move them to their own strip, so that they will always be off, except when
actually being used.

------
"We already know the answers -- we just haven't asked the right
questions." -- Edwin Land

I went from 400kwh a month to 200kwh but putting all vampire devices on
power strips and shutting things off that are not needed. My oil burner
alone takes 100kwh a month until I switched to pellets and wood boiler
when it's real cold. I like free hot water.

 

[Phil Hobbs]

William Sommerwerck wrote:

My understanding was that the watt-hour meter actually measure VA-hours.
I
asked the electric company once, and that said that was the case. But I
wasn't speaking with an engineer.

That's VARs, not VA-hours. For 'volt-ampere reactive'.

If you can have watt-hours, you can have VA-hours. Both are units of energy.

Is VAR a unit of energy? No, it's a unit of (reactive) power. Energy and
power are not the same.


Yes, of course. But a VA-hour is a meaningless unit unless you know the

power factor--real power costs money and fuel, whereas (apart from
transmission losses) reactive power just sloshes back and forth cycle by
cycle. That's why multiplying it by any period of time longer than a
cycle is meaningless.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal
ElectroOptical Innovations
55 Orchard Rd
Briarcliff Manor NY 10510
845-480-2058
hobbs at electrooptical dot net
http://electrooptical.net