Hi guys,
I'm sure I know the answer is "they're no 100% efficient", but just
wanted to check whether I have got some really wrong readings...or
whether I'm missing some vital text on the packet which says these
bulbs don't consume what they imply they consume...

NOw I may have been given a trojan horse of a bulb of course, but
npower sent me a load of energy efficient light bulbs a while back
(Philips branded).....I then received a free energy consumption
monitor more recently...so I decided to do the @nul thing and test
every individual appliance, bulb, cat and dog in the house as well as
'combinations' thereof to try to avoid the monitor giving crap
readings where the consumption was below a level it could read...or
where the increment was too small for it to notice.

Anyways...I came around to the 3 energy efficient bulbs from npower
that I'd put in a 3 way spot light in the kitchen. Turn the lights on
and the monitor shows 90W...I was somewhat surprised given I'd put in
an 11W + 11W + 8W bulb which according to the bumf would actually give
me about 60W + 35W + 35W = 130W equivalent in light..which as we all
know isn't quite true but either way...lumens aside...if the box says
11WATT IN (little green arrow saying "Energy" pointing INTO the
bulb...and big 60 WATT inside the bulb and the words "Light") surely
it's saying this is only supposed to consume 11 watts regardless of
what output it claims..so should be a total consumption of 31W..not 3
times that.
Similarly, I turn on 2 more 11W spots, and a further 2 x 12W softone
spots..so expecting a total consumption of the original 31 + 22 + 24 =
77W...the monitor reads 230W !

I know the energy consumption monitor thing 'could' be a bit rubbish
but it does appear to be linear based on all the other things I've
tested...so inclined to believe it's giving a fairly reasonable
estimate...but maybe a numberof you will fall of your chairs laughing
at me ;-) I know they're only supposed to be an indicator as opposed
to a measuring device...but I'm sure it can't be 'that' far out....

Have npower just sent me a load of innefficient bulbs hoping I'd leave
them on 3-5 times longer ? ;-)

Ant.

ant wrote:

I know the energy consumption monitor thing 'could' be a bit rubbish
but it does appear to be linear based on all the other things I've
tested...

Were all the other things you tested purely resistive loads (e.g.
kettle, incandescent lamps, heaters, oven etc)?

CFL lamps (and PCs, most phone chargers and wall warts) draw current in
a non-linear way, so are difficult to measure with the simple power meters.

On Nov 16, 2:54*pm, Andy Burns wrote:
ant wrote:
I know the energy consumption monitor thing 'could' be a bit rubbish
but it does appear to be linear based on all the other things I've
tested...

Were all the other things you tested purely resistive loads (e.g.
kettle, incandescent lamps, heaters, oven etc)?

CFL lamps (and PCs, most phone chargers and wall warts) draw current in
a non-linear way, so are difficult to measure with the simple power meters.

I measured everything...even the kids plugin night lights..for the PC/
chargers/Sky+/Dreambox/PS3/Amp I was aware the consumption would
fluctuate..but the meter was also showing that, so I was able to
compare 'normal' use (e.g difference between the plasma screen showing
light scenes versus dark scenes of a movie)...PC consumption would be
all over the place but I figured my desktop and network which are 24x7
are generally in an awake/active but low utilisation state so took
readings individually for the PC/NAS/Router etc and then combined as a
'working environment' kind of measure to get a decent figure.

Now...for the energy efficient bulbs, are you saying that they may
fluctuate in consumption so rapidly, that the meter would show a bad
reading or just show their peak consumption all the time ? or that
they need to be left to warm up for quite a long time before they drop
back to the 11W/14W etc consumption ? (or both !)

I'm thinking of going round the house and totting up all the Wattages
for the energy efficient bulbs I have installed...and turning them all
on simultaneously to see if they average out to a more reliable
reading...by the time the meter is getting up to 1Kw I'd expect it to
be in it's comfort zone for accuracy and If I can do that with just 20
or so bulbs..would sugest the readings I'm getting are reasonable (I
could also take a meter reading I guess......oh my kids and wife are
going to love me tonight !....sorry, 2 hours, lights only..)

Ant.

Andy Burns wrote:
ant wrote:

I know the energy consumption monitor thing 'could' be a bit rubbish
but it does appear to be linear based on all the other things I've
tested...

Were all the other things you tested purely resistive loads (e.g.
kettle, incandescent lamps, heaters, oven etc)?

CFL lamps (and PCs, most phone chargers and wall warts) draw current in
a non-linear way, so are difficult to measure with the simple power meters.

These monitors are potentially inaccurate when measuring small loads and
at all load levels are only going to measure power properly on resistive
loads like kettles, electric fires etc.
The meter on which your bill is based is sensitive to both current and
voltage and the relative phases of both and so can work out true AC
power consumed.

Bob

ant wrote:

for the energy efficient bulbs, are you saying that they may
fluctuate in consumption so rapidly, that the meter would show a bad
reading or just show their peak consumption all the time ?

With a "normal" bulb the current varies smoothly 100 times a second
(with each half of the mains cycle) however with a CFL the current will
typically vary tens of thousands of time per second, and the current
will be very spiky rather than a sine wave.

Therefore the current and voltage samples that the power meter reads are
not likely to be frequent enough to calculate power accurately.

they need to be left to warm up for quite a long time before they drop
back to the 11W/14W etc consumption ? (or both !)

If anything the true consumption is likely to go up when they've warmed
up to full brightness.

Andy Burns wrote:
ant wrote:

I know the energy consumption monitor thing 'could' be a bit rubbish
but it does appear to be linear based on all the other things I've
tested...

Were all the other things you tested purely resistive loads (e.g.
kettle, incandescent lamps, heaters, oven etc)?

CFL lamps (and PCs, most phone chargers and wall warts) draw current in
a non-linear way, so are difficult to measure with the simple power meters.

s/simple/badly designed.

On Nov 16, 2:41*pm, ant wrote:
Hi guys,
I'm sure I know the answer is "they're no 100% efficient", but just
wanted to check whether I have got some really wrong readings...or
whether I'm missing some vital text on the packet which says these
bulbs don't consume what they imply they consume...

NOw I may have been given a trojan horse of a bulb of course, but
npower sent me a load of energy efficient light bulbs a while back
(Philips branded).....I then received a free energy consumption
monitor more recently...so I decided to do the @nul thing and test
every individual appliance, bulb, cat and dog in the house as well as
'combinations' thereof to try to avoid the monitor giving crap
readings where the consumption was below a level it could read...or
where the increment was too small for it to notice.

Anyways...I came around to the 3 energy efficient bulbs from npower
that I'd put in a 3 way spot light in the kitchen. Turn the lights on
and the monitor shows 90W...I was somewhat surprised given I'd put in
an 11W + 11W + 8W bulb which according to the bumf would actually give
me about 60W + 35W + 35W = 130W equivalent in light..which as we all
know isn't quite true but either way...lumens aside...if the box says
11WATT IN (little green arrow saying "Energy" pointing INTO the
bulb...and big 60 WATT inside the bulb and the words "Light") surely
it's saying this is only supposed to consume 11 watts regardless of
what output it claims..so should be a total consumption of 31W..not 3
times that.
Similarly, I turn on 2 more 11W spots, and a further 2 x 12W softone
spots..so expecting a total consumption of the original 31 + 22 + 24 =
77W...the monitor reads 230W !

I know the energy consumption monitor thing 'could' be a bit rubbish
but it does appear to be linear based on all the other things I've
tested...so inclined to believe it's giving a fairly reasonable
estimate...but maybe a numberof you will fall of your chairs laughing
at me ;-) I know they're only supposed to be an indicator as opposed
to a measuring device...but I'm sure it can't be 'that' far out....

Have npower just sent me a load of innefficient bulbs hoping I'd leave
them on 3-5 times longer ? ;-)

Ant.

You need to look at the instructions carefully. Power is measured in
Watts (or Kilowats) If it is a true "power meter" it measures watts
full stop.

Be very sure it does not have a Va (volt x ampere) range.
This is the same as watts on resistive loads (heating and conventional
light bulbs) but NOT the same with motors, transformers and one or two
tricky electronic devices (eg some CFLs).

It seems likely to me you have the machine set on the Va range instead
of Watts.
The other possibilty is that there is a calibration problem with your
gadget. You need to check it against a known resistive load of about
the same value as your CFLs. (Eg a conventional light bulb.) to see
if this is the case.

On Nov 16, 2:41*pm, ant wrote:
Hi guys,
I'm sure I know the answer is "they're no 100% efficient", but just
wanted to check whether I have got some really wrong readings...or
whether I'm missing some vital text on the packet which says these
bulbs don't consume what they imply they consume...

NOw I may have been given a trojan horse of a bulb of course, but
npower sent me a load of energy efficient light bulbs a while back
(Philips branded).....I then received a free energy consumption
monitor more recently...so I decided to do the @nul thing and test
every individual appliance, bulb, cat and dog in the house as well as
'combinations' thereof to try to avoid the monitor giving crap
readings where the consumption was below a level it could read...or
where the increment was too small for it to notice.

Anyways...I came around to the 3 energy efficient bulbs from npower
that I'd put in a 3 way spot light in the kitchen. Turn the lights on
and the monitor shows 90W...I was somewhat surprised given I'd put in
an 11W + 11W + 8W bulb which according to the bumf would actually give
me about 60W + 35W + 35W = 130W equivalent in light..which as we all
know isn't quite true but either way...lumens aside...if the box says
11WATT IN (little green arrow saying "Energy" pointing INTO the
bulb...and big 60 WATT inside the bulb and the words "Light") surely
it's saying this is only supposed to consume 11 watts regardless of
what output it claims..so should be a total consumption of 31W..not 3
times that.
Similarly, I turn on 2 more 11W spots, and a further 2 x 12W softone
spots..so expecting a total consumption of the original 31 + 22 + 24 =
77W...the monitor reads 230W !

I know the energy consumption monitor thing 'could' be a bit rubbish
but it does appear to be linear based on all the other things I've
tested...so inclined to believe it's giving a fairly reasonable
estimate...but maybe a numberof you will fall of your chairs laughing
at me ;-) I know they're only supposed to be an indicator as opposed
to a measuring device...but I'm sure it can't be 'that' far out....

Have npower just sent me a load of innefficient bulbs hoping I'd leave
them on 3-5 times longer ? ;-)

Ant.

The important thing for your wallet is what the Electric Co's meter
reads as the consumption. Does your house meter allow readings of
1/10 kwh so consumption could be checked by leaving the bulbs on for
several hours.

rusty

therustyone wrote:

Does your house meter allow readings of
1/10 kwh so consumption could be checked by leaving the bulbs on for
several hours.

No need to take so long as that, you can check power consumption in just a
few minutes by watching the supply meter. The meter will have either a
rotating disk below the dials (if the old analogue type) or a flashing led
(if the newer digital type). Either way the front of the meter will be
marked to indicate how many rotations or flashes correspond to 1 KWh. On
our digital meter it's 1000 flashes per KWh, so if it flashed 1000 times
per hour (3.6 seconds per flash) you have a 1KW load and if the OP had only
his kitchen light with 2 x 11W and 1 x 8W CFLs (= 30W) connected it should
be 3.6 x 1000/30 = 120 seconds per flash. That's with a meter like ours,
other meters might have a different rate of flashes or turns but the
principle would be the same.

--
Mike Clarke

On Nov 17, 10:42*am, Mike Clarke wrote:
therustyone wrote:
Does your house meter allow readings of
1/10 kwh so consumption could be checked by leaving the bulbs on for
several hours.

No need to take so long as that, you can check power consumption in just a
few minutes by watching the supply meter. The meter will have either a
rotating disk below the dials (if the old analogue type) or a flashing led
(if the newer digital type). Either way the front of the meter will be
marked to indicate how many rotations or flashes correspond to 1 KWh. On
our digital meter it's 1000 flashes per KWh, so if it flashed 1000 times
per hour (3.6 seconds per flash) you have a 1KW load and if the OP had only
his kitchen light with 2 x 11W and 1 x 8W CFLs (= 30W) connected it should
be 3.6 x 1000/30 = 120 seconds per flash. That's with a meter like ours,
other meters might have a different rate of flashes or turns but the
principle would be the same.

--
Mike Clarke

THanks for all the responses here...very interesting info. I'll find a
suitable time to power down the whole house ! and report back with my
findings by reading off the meter...

On Nov 18, 10:48*am, Ant wrote:
On Nov 17, 10:42*am, Mike Clarke wrote:



therustyone wrote:
Does your house meter allow readings of
1/10 kwh so consumption could be checked by leaving the bulbs on for
several hours.

No need to take so long as that, you can check power consumption in just a
few minutes by watching the supply meter. The meter will have either a
rotating disk below the dials (if the old analogue type) or a flashing led
(if the newer digital type). Either way the front of the meter will be
marked to indicate how many rotations or flashes correspond to 1 KWh. On
our digital meter it's 1000 flashes per KWh, so if it flashed 1000 times
per hour (3.6 seconds per flash) you have a 1KW load and if the OP had only
his kitchen light with 2 x 11W and 1 x 8W CFLs (= 30W) connected it should
be 3.6 x 1000/30 = 120 seconds per flash. That's with a meter like ours,
other meters might have a different rate of flashes or turns but the
principle would be the same.

--
Mike Clarke

THanks for all the responses here...very interesting info. I'll find a
suitable time to power down the whole house ! and report back with my
findings by reading off the meter...

RIght...looks like this now makes sense ;-)

I powered the whole place down then turned on as many energy efficient
lights as I could find accessible and totalled the Wattage for them up
to 126W
I then took meter readings every 10 minutes and after 1 hour had used
very approximately 0.28 Kwh however my wife came home in the middle of
my test and I inadvertaintly, being a good husband...put the kettle
on...Doh!. Anyway, I reboiled after the readings to figure out it used
about 0.042Kwh (2.6Kw for 1 Min) ...subtrating that from my reading
gives 0.238 Kwh implying a draw of 240W which is double the ratings of
the sum of those bulbs but not as bad as my original readings
looked...I need to therefore run this for a longer period, and without
boiling the kettle ;-)

Incidently, My meter has 800 Imp/Kwh next to the flashing light and I
recorded about 29 seconds between flashes (eliminating the kettle
error)...that works out as 1 Hour / 29 Seconds = 124 FLashes.......
124 / 800 = 0.155 Kwh...so 155 Watts which is much closer to what
those bulbs added up to...


Ant.

ant wrote:

RIght...looks like this now makes sense ;-)

I powered the whole place down then turned on as many energy efficient
lights as I could find accessible and totalled the Wattage for them up
to 126W
I then took meter readings every 10 minutes and after 1 hour had used
very approximately 0.28 Kwh however my wife came home in the middle of
my test and I inadvertaintly, being a good husband...put the kettle
on...Doh!. Anyway, I reboiled after the readings to figure out it used
about 0.042Kwh (2.6Kw for 1 Min) ...subtrating that from my reading
gives 0.238 Kwh implying a draw of 240W which is double the ratings of
the sum of those bulbs but not as bad as my original readings
looked...I need to therefore run this for a longer period, and without
boiling the kettle ;-)

Incidently, My meter has 800 Imp/Kwh next to the flashing light and I
recorded about 29 seconds between flashes (eliminating the kettle
error)...that works out as 1 Hour / 29 Seconds = 124 FLashes.......
124 / 800 = 0.155 Kwh...so 155 Watts which is much closer to what
those bulbs added up to...

You have a problem here, because you've got two conflicting answers,
one based on the meter reading and one on the flash rate. Since they're
both from the same meter, the results you get should be the same!

Your flashes tell you 155W, your readings tell you 238W. The ratio
is about 0.65, and coincidentally that's also the ratio of 19 to 29.
Are you sure the flash intervals weren't 19 seconds instead of 29?

On Nov 18, 4:33*pm, Ronald Raygun
wrote:
ant wrote:
RIght...looks like this now makes sense ;-)

I powered the whole place down then turned on as manyenergyefficient
lights as I could find accessible and totalled the Wattage for them up
to 126W
*I then took meter readings every 10 minutes and after 1 hour had used
very approximately 0.28 Kwh however my wife came home in the middle of
my test and I inadvertaintly, being a good husband...put the kettle
on...Doh!. Anyway, I reboiled after the readings to figure out it used
about 0.042Kwh (2.6Kw for 1 Min) ...subtrating that from my reading
gives 0.238 Kwh implying a draw of 240W which is double the ratings of
the sum of those bulbs but not as bad as my original readings
looked...I need to therefore run this for a longer period, and without
boiling the kettle ;-)

Incidently, My meter has 800 Imp/Kwh next to the flashing light and I
recorded about 29 seconds between flashes (eliminating the kettle
error)...that works out as 1 Hour / 29 Seconds = 124 FLashes.......
124 / 800 = 0.155 Kwh...so 155 Watts which is much closer to what
those bulbs added up to...

You have a problem here, because you've got two conflicting answers,
one based on the meter reading and one on the flash rate. *Since they're
both from the same meter, the results you get should be the same!

Your flashes tell you 155W, your readings tell you 238W. *The ratio
is about 0.65, and coincidentally that's also the ratio of 19 to 29.
Are you sure the flash intervals weren't 19 seconds instead of 29?

the flashes were definately 29 seconds but I think the discrepancy is
more likely to be the meter readings I took (since it's very difficult
to read the 1/10th markings on the 1/10th scale (i.e 1/100ths)..to be
honest I didn't even realise the 1/10ths were subdivided until I
looked closely, and since the reader only clocked up 3/10ths during
the hour mixed in with a silly kettle boil I figured the meter reading
was likely to be erroneous...I'm going to retest over the weekend if I
get chance as I don't like conflicting answers either !
Ant.