Unaccountable power consumption through residential meter box

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Unaccountable power consumption through residential meter box

(18 posts) (8 voices)

Started 1 year ago by tonydp
Latest reply from souri

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tonydp
Member

We are trying to identify some unaccountable power consumption recorded through our power meter box.

We recently took advantage of the QLD Government ClimateSmart initiative. This provides consumer advice for the more efficient use of electricity resources.

Part of the ClimateSmart package included the provision of energy efficient light bulbs and a monitoring device that is attached to the electricity meter and can be monitored remotely. There have been some comments in other forums that these monitors may not be exceedingly accurate (however this is of no concern to this posting).

We have also recently installed a grid connected solar power system (1.5KW) and was informed that the monitor would not be able to detect the direction of current flow to or from the grid (however this is too of no concern to this posting).

Being a gadget nerd, I decided to do a few experiments using the monitor and encountered the following incidental results.
• our air conditioning unit that we use less than 4 times per year was consuming 120W even when only in Standby mode (saving $224 pa when powered off at switch board)
• an intelligent power board we use for the home theatre equipment was consuming 50W even when all devices had been switched off (saving $93 pa when powered off)

Even with the knowledge of these devices we could not determine how my wife and I were consuming an average of 12.6 KWh per day.

We live in Queensland and our house is only 3 years old with a single meter box. So we progressively turned off all power and light circuits using the breaker switches in the meter box (including the safety switches). This was done after the sun had gone down to ensure that our solar system would not influence the result (our SamilPower solar inverter only ever uses its own power)

With all switches turned off the power monitor was still showing 94 - 163W of current going through the power meter. This equates to 2.2 - 3.9KWh ($175 - $304pa) of power going through the meter box without any explanation of where it is being consumed.

Are we misinterpreting something, or is this normal, or can anyone explain what may be causing this unaccountable power consumption?

Posted Thursday 28 Apr 2011 @ 2:15:56 am from IP #
rockabye
Member

Firstly check if the electricity meter in the power box is recording any power use. If it is then something is using power somewhere. If it is not indicating any power use and your portable energy meter is still showing a reading then it may need resetting or it could be faulty.

Posted Thursday 28 Apr 2011 @ 2:47:55 am from IP #
ghostgum
Member

If the monitor is of the current clamp variety (sensor is clamped around a wire in the switchboard/ meter box, with no other connections), then it will measure volt-amps not watts. Standby loads often have poor power factor, so will read high.

As an example, my current clamp reads about 1kWh per day higher than the distributor's energy meter.

I suggest you get a plug-in energy meter (I've got the Power-mate Lite), and measure the daily power use of the main appliances. If you add up the standby power for each appliance, it will add up to more than the standby power you measure with your single current clamp meter. Don't be too worried by this. But you should be able to find all appliances using more than 0.5kWh per day.

Posted Thursday 28 Apr 2011 @ 2:50:38 am from IP #
swanning_it
Member

Mine was the same.

I've gone right through and isolated everything and yet the meter still showed a 100W or so. I personally think it's a meter issue and just use it as an indication, rather than the gospel truth.

I bought an Arlec plug in from Bunnings for about $22 for measuring plug in appliances.

Posted Thursday 28 Apr 2011 @ 3:56:17 am from IP #
ghostgum
Member

The cheap meters (i.e. < $100) are likely to give you as much fiction on standby loads as a simple current clamp meter.

My cheap meter (similar to Arlec) reads about 10-30W on my central heater. A better meter reads 3W and 30VA standby.

Posted Thursday 28 Apr 2011 @ 6:19:23 am from IP #
hamish05
Member

tonydp, I have experienced similar problems Check.....

http://www.ata.org.au/forums/topic/energy-audit

Posted Thursday 28 Apr 2011 @ 6:36:19 am from IP #
tonydp
Member

rockabye:

The electricity meter in the power box seems to be recording power usage OK. Since we turned off the air cond and the intelligent power board and are now turning off some devices when not in use as well as setting our laptops into "hibernate mode" when not in use our average daily consumption has reduced from 12.6 KWh per day to less than 7.4 KWh per day (recorded over the last 10 days). So things are looking good especially considering our 1.5KW Solar system is averaging 5 KWh per day even though it has been predominately cloudy for the last couple of weeks.

ghostgum:

I think it is of the clamp variety and it can't separate reading when using the grid energy as opposed to the solar energy we are placing back into the grid (there is no positive or negative indicator on the monitor). We will look at getting one of those plug-in energy meters. Do you think it would help us find our 'missing' 2.2 - 3.9KWh per day?

swanning_it:

Have you been able to identify the problem yet? If it were a meter issue then 100W for 24hrs per day equates to 2.4 KWh per day which is a non-trivial $187.00 per year on our tariff especially the way electricity prices are continually increasing lately.

We have crudely measured (using the supplied monitor) the standby consumption on most of our devices and apart from the air cond and power board they recorded less than 5W each. This included such things as the microwave, oven, phone charger, electric toothbrush, wireless modem, sewing machines, wireless printer, etc. As part of the 2 separate tests we ran all of these devices were of course turned off at the meter box.

Has anyone else tried turning off all breaker and safety switches (not the main switch) at the distributor's meter box and been able to record any readings through the meter box?

If we could identify and possibly remove this load we could come close to a break even situation for energy consumed versus energy generated by our solar system. That would be nice!!!

Posted Friday 29 Apr 2011 @ 3:26:41 am from IP #
hamish05
Member

My refrigerator/s are my biggest users of power (presumably yours are also), have you taken steps to reduce their contribution?
i.e. checked they are not running too cold, and improved the ventilation around the compressor? I found that I achieved brilliant power reductions by improving the ventilation in particular, in fact that modification saved me purchasing a more efficient one.

Have you checked security lights and alarm? they all consume standby power, also the garage door actuator/s.

Posted Friday 29 Apr 2011 @ 3:54:14 am from IP #
tonydp
Member

Yes we have read with interest your other referenced posting (still trying to digest it all). It did highlight to us that we do not have much ventilation around our refrigerator so we are looking to see whether we can at least ventilate through the ceiling in the refrigerator recess (unfortunately our house is slab on ground and therefore no opportunity for bottom ventilation).

There is only my wife and I in the house so access to the frig is fairly controlled and it is a new frig with digital controls located in the centre of the house. We haven't previously bothered to check the settings (we will now). It's manufacturer's rating is 805 kWh (2.2 kWh per day) which is quite a hefty portion of our daily consumption.

We have a movement sensor light either end of the house and an electic garage door, so we will check these out as well. Thanks for the advice.

Posted Friday 29 Apr 2011 @ 5:12:23 am from IP #
ghostgum
Member

tonydp, if the clamp on meter is on the wire to the street (i.e. is measuring net energy), then it will give you an incorrect reading if you are both importing energy at night and exporting energy during the day. The problem is that it measures the absolute value of the power, and so there isn't enough information to work out afterwards the direction of the energy flow.

You will need to make sure the clamp is only on the wire(s) to the house load, and that it does not measure anything from the PV solar.

Posted Friday 29 Apr 2011 @ 6:33:38 am from IP #
LaSource
Member

You mentioned your laptops. I supposed you checked them but here is some tips. Using a power point meter will have told you this but many people switch off there laptop, even disconnect there laptop but the power brick continues to consume 6-10 watts. Switch off at the wall is the only sure way. There may even be value in removing the laptop battery when the likelihood of going mobile is low (ie always plugged in) because this adds to the power consumption maintaining the battery in a charged state (However the batteries are one form of UPS Uninterruptible power supply). You need to read about the batteries care instructions before you do that.

If as in most houses the power point is inaccessible see the ATA website for an Eco Switch to bring the switch into easy access.

Tony

Tony

Posted Friday 29 Apr 2011 @ 9:24:07 am from IP #
RodD
Member

Going back to initial post
• an intelligent power board we use for the home theatre equipment was consuming 50W even when all devices had been switched off (saving $93 pa when powered off)

There are some better versions of these out now, the one I use for my AV equipment uses less that 1 Watt in standby. I got mine from here http://www.energy-monitor.com.au

With regard to your fridge manufacture specification are not always accurate as they are not representative of actual circumstances that your fridge is operating under. Measure your fridge consumption over a week with a power point monitor to get some solid data.

If your fridge was manufactured after 1/1/2005 you should be able to find it listed at http://www.energyrating.gov.au/index.html. One way or another you need to work out if your fridge is the issue.

Posted Friday 29 Apr 2011 @ 10:43:40 am from IP #
souri
Member

I did the same thing a while ago and tried to get my Standby consumption to 0 ... no success. I still had around 75Watt left. But I left a few things on ... some convenience.

Things I did not turn off:

- Fridge
- Garage Door Remote Controlled system
- Pool Pump on standby
- Watering system for garden
- Sensor light at front
- greywater system pump
- WLAN (Internet Router)
- the energy meter itself
- Wireless landline telephone

Thing I identified with high standby usage:

- Microwave on standby (35W !!!)
- my old bedside alarm clock (30W !!!)
- aircon standby (150W)

Since I have a energy meter installed and see what my house uses all the time I am a little more caution about the consumption. I got my average usage down fro 15kWh to around 10kWh ... 30% reduction!

I can only suggest to look really carefully if you really have switched off everything ... I bet you will find a few devices which are still running or on standby.

Posted Friday 29 Apr 2011 @ 11:49:08 am from IP #
swanning_it
Member

tonydp, I switched everything off at the switchboard and ensured the clamp was on the loads supply only. So to answer your question, yes I believe I have identified my problem......the "elite" branded meter inaccuracy!

Posted Friday 29 Apr 2011 @ 8:58:29 pm from IP #
rockabye
Member

Try unclipping the sensor from the power lead and see if it drops to zero. If not it is crook.

I got one of the early units and it reads zero unless at least 20W is being used, then it reads 50.

Posted Friday 29 Apr 2011 @ 11:10:06 pm from IP #
ghostgum
Member

Souri writes:
"Thing I identified with high standby usage:
- Microwave on standby (35W !!!)
- my old bedside alarm clock (30W !!!)
- aircon standby (150W)"

I don't believe the first two. Your power meter is likely to be inaccurate for low standby loads. I expect the microwave standby power is more likely 10W, and the alarm clock 2-10W. The aircon is likely to be lower than 150W, but still high enough that it is worth turning it off when not in use.

Posted Saturday 30 Apr 2011 @ 1:02:09 am from IP #
hamish05
Member

That's correct ghostgum, Possibly a decimal point error, my microwave is 3W and my (no longer used) clock radio 3.7W.

Posted Saturday 30 Apr 2011 @ 6:00:39 am from IP #
souri
Member

@ghostgum and hamish05
hehe ... looks like I was not really precise:

ALARMCLOCK
My alarmclock is over 20 years old (from Germany) and has a wireless connection to some kind of timeserver (Funkuhr) in Europe (haha ... we had that 20 years ago in Germany ...). That means you never need to set your clock it always is exact on the second and swaps to daylight saving time automatically. As we do not have this signal in Australia the clock always tries to connect but is unsuccessful. (In germany it would only do this once a day.) So maybe this explains the 30W. I replaced it witch a standard one ... and I am down to around 5W :-).
It just shows that the energy monitor is really helpful. Hehe .

AIRCONS
There are 4 units installed at my house (ridiculous ... I know ... but they came with the house when we bought it). So it is around 37W per unit ... still high.

MICROWAVE
35W ! ... very expensive clock. I also would expect around 3W ... maybe I have a really stupid model. A friend of mine tried a different meter and had a similar result with his microwave. So maybe there are some differences.
Check out these reviews (I also have a Panasonic): http://www.productreview.com.au/p/panasonic-nn-st676m.html

By the way: here is the link to the ClimateSmart Home Service.
http://www.climatesmarthome.com/
Great deal when you are in QLD.

Posted Tuesday 3 May 2011 @ 2:11:11 am from IP #

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