EnergyNote meter's readings 70% higher than utility meter, why?
21
2.1 years ago by
dain180
dain180 wrote:

Just wondering if anyone else had this happening, it seems that the EnergyNote's clip-on meter gives consistently higher readings than the utility meter.

Looking at my utility bill, in the months Jan-Mar we used 467kWh, but looking at the EnergyNote analysis page, the same period shows 810kWh used.

I know that this non-invasive clip-on meter isn't going to give perfect readings, and I might have very well installed it incorrectly, so this post is not trying to give bad rep to the EnergyNote meter, just wanting to find out what's going on.

So, anyone had similar issues or has an idea what I might have done wrong?

meter analysis • 831 views
link modified 22 months ago by lmccann130 • written 2.1 years ago by dain180
1
22 months ago by
lmccann130
Milton Keynes
lmccann130 wrote:

@darius_s, It might helps us to understand your problem if you could share a typical days consumption readings from the Analysis section of the energynote web site. At any point in time the Clamp will be recording total home consumption so will change second by second as fridge's/freezers & boiler etc operate. Mine look like this. If your smart plug is really doubling your figures is should show up.

"During this period your house used a total of 15.3 kWh.

Of your use:

  • 12.9% was from your Heater (2.0 kWh)
  • 13.9% was from your Computing Equipment (2.1 kWh)
  • 20.1% was from your Lighting (3.1 kWh)
  • 8.5% was from your Garden Equipment (1.3 kWh)
  • 2.7% was from your Washing Machine (0.42 kWh)
  • 0.2% was from your Appliance (0.030 kWh)"
link written 22 months ago by lmccann130
1
22 months ago by
lmccann130
Milton Keynes
lmccann130 wrote:

@darius_s, Finally got some figures for you. As we have a Smart meter I am able to do a comparison between the Geo clamp and 'official' consumption. The figures do show that depending on the nature resistive/reactive type of load and size of load a slight difference in readings. So my installation  seems to be getting 'correct' readings.

Smart Geo Clamp Plug Smart-Base Geo-Base Dif Geo Dif Smart Item
0.39 0.41           Background
2.72 2.4 2.30 2.33 1.99 0.31 0.34 Kettle
1.03 1.1 0.64 0.64 0.69 -0.05 -0.05 Air Con
2.33 2.1 1.90 1.94 1.69 0.21 0.25 Washer
3.55 3.4 3.00 3.16 2.99 0.01 0.17 Immersion
link written 22 months ago by lmccann130
0
2.1 years ago by
dain180
dain180 wrote:

Thanks a lot for your answer @riktemmink!

The utility bill usage is based on two readings I had to submit, so that should be accurate (see screenshots below). Also, no connected solar panels (the ones on our roof are owned by the housing association) or any other generating device.

What I did notice though is a quite high base load (200W+) I could never account for, though I haven't yet got around to do a proper fuse board bingo.

Maybe it's an issue of relatively high non-sinusoidal load percentage?

We have gas heating, so most of the ongoing usage comes from LED lights, computer equipment, sound system, fridge and an extractor fan. The short usage like kettle, washing machine, dishwasher, toaster, etc seem to show up correctly when looking at the display, but all our appliances are energy saving ones so we're talking ~1kWh per wash / dish cycle for example.

link written 2.1 years ago by dain180
1
22 months ago by
js200
js200 wrote:

I have the same issue and these errors could explain my high base load.

A current clamp is never going to be as accurate as a meter. It only measures current and only samples this every few seconds.

To get a full picture you need to sample both the current and voltage many times a second. This will let you calculate the true power and you can also take into account the phase shift to work out the imaginary component / reactive load / power factor. It's complex but for domestic installations you are typically only billed for real power (they assume a simple resistive load).

If you want better data then you could look at openenergymonitor.org or it's possible to optically tap into some meters to log the power use.

link written 22 months ago by js200
0
22 months ago by
darius_s20
darius_s20 wrote:

Right, here is some data for you to have a look. It is from last evening when I did not have other significant loads, apart from my PC.

 

Data from the plug. 

Date (yyyymmdd hh:mm) Cost (£) Extra Cost (£) Consumption (kWh) Carbon (kg)
20160825 20:45 0.00574 0 0.058 0.03115
20160825 21:00 0.00584 0 0.059 0.03168
20160825 21:15 0.00584 0 0.059 0.03168
20160825 21:30 0.00584 0 0.059 0.03168
20160825 21:45 0.00178 0 0.018 0.00967
20160825 22:00 0.0001 0 0.001 0.00054
20160825 22:15 0.0001 0 0.001 0.00054
20160825 22:30 0.0002 0 0.002 0.00107
20160825 22:45 0.0001 0 0.001 0.00054
20160825 23:00 0.0001 0 0.001 0.00054
20160825 23:15 0.0001 0 0.001 0.00054
20160825 23:30 0.0002 0 0.002 0.00107
20160825 23:45 0.0001 0 0.001 0.00054

 

Data from the clamp

 

Date (yyyymmdd hh:mm) Cost (£) Extra Cost (£) Consumption (kWh)

Carbon (kg)

20160825 20:45 0.01089 0 0.11 0.05907
20160825 21:00 0.01287 0 0.13 0.06981
20160825 21:15 0.0099 0 0.1 0.0537
20160825 21:30 0.01287 0 0.13 0.06981
20160825 21:45 0.00495 0 0.05 0.02685
20160825 22:00 0.00396 0 0.04 0.02148
20160825 22:15 0.00792 0 0.08 0.04296
20160825 22:30 0.00198 0 0.02 0.01074
20160825 22:45 0.00396 0 0.04 0.02148
20160825 23:00 0.00198 0 0.02 0.01074
20160825 23:15 0.00297 0 0.03 0.01611
20160825 23:30 0.00396 0 0.04 0.02148
20160825 23:45 0.00099 0 0.01 0.00537

I have switched off my PC somewhere before 10 pm. The total usage has dropped almost twice the PC consumption. Almost, because we have switched on some extra lights.

I had a look at watage before and after switching off PC and I could clearly see that it dropped twice the plug amount.

 

From what I can understand, no one else has the same problem.

A suggestion would be for someone to do an experiment.

While not having big loads in the house, could you plug let's say kettle. Have a look at wattage before switching it on. Then switch it on and have a look at the both total wattage and the one for kettle alone. 

What are your results?

link written 22 months ago by darius_s20
0
22 months ago by
lmccann130
Milton Keynes
lmccann130 wrote:

@darius_s, Thank you for the figures, which putting on one side your kettle test look OK to me. Taking the Clamp reading away from the Plug reading gives a figure for the Other or background consumption. Then taking an average of the including PC and excluding PC shows a difference of 0.06 -0.04 = 0.02 kWh, see table below. The background consumption varies from 0.02 to 0.08. As to accuracy the Clamp is only giving you two significant digit accuracy which is probably rounded up so that does not help. I will have a think about the kettle, cannot check at moment as wife is ironing which is a 2kW intermittent load!

Time Plug kWh Clamp kWh Other kWh

20160825 20:45

0.058 0.11 0.05
20160825 21:00 0.059 0.13 0.07
20160825 21:15 0.059 0.10 0.04
20160825 21:30 0.059 0.13 0.07
Average inc PC 0.059 0.12 0.06
20160825 21:45 0.018 0.05 0.03
20160825 22:00 0.001 0.04 0.04
20160825 22:15 0.001 0.08 0.08
20160825 22:30 0.002 0.02 0.02
20160825 22:45 0.001 0.04 0.04
20160825 23:00 0.001 0.02 0.02
20160825 23:15 0.001 0.03 0.03
20160825 23:30 0.002 0.04 0.04
Average ex PC 0.003 0.04 0.04

 

link written 22 months ago by lmccann130
0
2.1 years ago by
riktemmink20
riktemmink20 wrote:

That's unusual - it definitely doesn't sound like an inaccuracy issue (because the CT clip has an accuracy range of +/- 10%), and if the clip was not fitted correctly, the readings on energynote would in most cases be lower than your actual consumption.

The only two things I can think of are:

  • The 467 kWh on your bill is an estimate, not actual usage.
  • You have solar panels or another type of microgeneration capability, in which case the CT clip will count energy imported from and exported to the grid, making the readings too high.
link written 2.1 years ago by riktemmink20
0
2.1 years ago by
planetcooler20
planetcooler20 wrote:

I have the same problem with the meter over reading. However, very early on, I was told that this would happen if I have PV - which I do. Are you sure that the solar panels on your roof don't go through your meter? Even if the panels aren't owned by you - they very probably connect to the grid through your meter. (Do you have an inverter in the loft? )  

link written 2.1 years ago by planetcooler20
0
22 months ago by
planetcooler20
planetcooler20 wrote:

Yes - the clamp cannot distinguish between import and export - so just measures net current flow.  I gave up trying to get any sense from  the Geo device  because of the import /export problem. Have to use my Utility supplied "Smart" meter which does measure Export, and my (separate) PV generation meter,  to get a handle on the amount of import / export. The so-called "Smart" meter cannot interface with my PV generation meter, or my heat Generation meter - (from my ground source heat pump). So the "Smartness" is pretty useless in terms of overall energy analysis  - just allows the utility to read my usage remotely, and to do tariff switching whenever they want to. Hopeless!! So much for Smart metering etc.........all of the technology is available in the Smart meter - nobody "Smart" enough to come and do the interfacing.............. 

link written 22 months ago by planetcooler20
0
2.1 years ago by
dain180
dain180 wrote:

@planetcooler no, unfortunately those panels are definitely not connected to our meter, I wish they were!

link written 2.1 years ago by dain180
0
22 months ago by
lmccann130
Milton Keynes
lmccann130 wrote:

We have a Smart meter and compared the daily readings for 24 days in April/May this year.

Smart Meter = 355kWh; GeoClamp = 356.2 kWh.

We do not have any PV.

I am wondering if the GeoClamp cannot distinguish between import & export so the reading 'dain' is getting is the sum of both figures?

link written 22 months ago by lmccann130
0
22 months ago by
lmccann130
Milton Keynes
lmccann130 wrote:

Planetcooler, thanks for quick contribution. So 'dain' maybe could subtract the Energynote figure of 819kWh from 467kWh of utility bill and get  352kWh being an approximate figure of  export energy from their housing association PV array?

 

link written 22 months ago by lmccann130
0
22 months ago by
darius_s20
darius_s20 wrote:

I have got my usages doubled. I have got a clamp and smart plug (as probably many of you).

As most of the usage is currently going through the plug, I can clearly see that it is the case. Am my missing some settings? Or should I use or clamp, or smart plug?

link written 22 months ago by darius_s20
0
22 months ago by
Laser120
Southampton
Laser120 wrote:

@darius_s could you clarify your questions? usage doubled where? between the bill and clamp reading? 

most of the usage going through which plug? what is plugged into the plug? 

what do you mean should you use a clamp or smart plug? aren't using them already? what do you want to measure? 

link written 22 months ago by Laser120
0
22 months ago by
darius_s20
darius_s20 wrote:

@Laser Right, I will try to be more detailed :) 

I have got my PC and screens and a couple other bits running through the smart plug. At the point of checking, they accounted for around 240W. At the same time, the total for the household was 500W (as shown on energy monitor).

As I we have quite a small flat, I am sure that there were no other significant loads. So it seems that usage of my workstation was accounted twice, first time through the plug and then through the clamp.

Following day, I have removed the smart plug and the total usage was in line with what is expected. 

 

I would have thought that clamp would show the total and smart plugs should not contribute to the total, but it does not seem to be the case. Or did I somehow set up my unit incorrectly?

 

I still need to double check usages against electricity meter. It seems that I am still using more than I would normally use. I looked at the billed usage for the last year and calculated daily average. I have set it as a goal, but did not achieve it every day. As far as I know, nothing has changed since last year, so it is worth double checking.

I will report my findings.

link written 22 months ago by darius_s20
0
22 months ago by
darius_s20
darius_s20 wrote:

Right, I have just done the experiment. I have plugged kettle through smart plug. The results are really interesting.

Before switching on, wattage was around 0.065 kW.

After switching on:

Plug = 2.1 kW.

Total= 3.3 kW.

Total is around 50% bigger...

There is something not right.

link written 22 months ago by darius_s20
0
22 months ago by
darius_s20
darius_s20 wrote:

@Imccann  One small correction, the values are rounded to decimal places.. But that does not change anything in this case.

The difference of 0.02 kWh is in line with the test. PC was consuming 0.06 kWh. 50% of that is 0.03 kWh. I would suspect that 0.01 kWh was lost through multiple roundings :)

I am curious if your test will show something similar.

 

link written 22 months ago by darius_s20
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