Efergy smart meter accuracy.

markbloke

The efergy smart meter is clip-on type electricity usage meter much like the owl and eon types. I thought I'd compare the energy supplier's meter readings (the one in the cupboard) against those logged by the efergy in order to test its accuracy. Here are the results of my trial run.

Meter units logged: 204 kwh
Efergy units logged: 183 kwh

This means the efergy meter has logged around 90% of the actual use I end up paying for.

Personally I found the efergy to be a useful tool in my efforts to reduce consumption, I present these results so others may draw their own conclusions.

1carminestocky

I think that's pretty good, tbh. I have the Owl and therefore can't log this data due to it not having a memory function, but am happy enough with its perceived accuracy. My kitchen has 3x 50w halogen bulbs in a fitment (yes, it's going to get replaced before Winter, lol) and I have done this many times: Hold the Owl monitor and switch the lights on. The Owl immediately shows a 150 watt imcrease on the readout, swith the lights off and it shows a 150 watt decrease. This has happened too many times for it to be co-incidence.

scope

Continuing on the same subject.. I've just got my OWL and are trying to see how accurate it is.. Firstly is only shows 0.5kwh as a "normal" usage in my house - thats with 1 fridge, 1 freezer, couple of computers, 37" plasma and some other gadgets (none using much electricity) running.. Im not sure if this is correct as it sounds a bit low to me.. However, the issues I've got is that when I switch on my 3000w fan heater (not cold, just testing it. ) the meter only goes up by 1.5kwh, the same when my 3kwh kettle is boiling, the owl does not go up the 3kwh I would expect it to go up by.. Can anybody please explain why this is? If its so un-accurate I rather return it, as its pointless..

1carminestocky

scope wrote: »

Continuing on the same subject.. I've just got my OWL and are trying to see how accurate it is.. Firstly is only shows 0.5kwh as a "normal" usage in my house - thats with 1 fridge, 1 freezer, couple of computers, 37" plasma and some other gadgets (none using much electricity) running.. Im not sure if this is correct as it sounds a bit low to me.. However, the issues I've got is that when I switch on my 3000w fan heater (not cold, just testing it. ) the meter only goes up by 1.5kwh, the same when my 3kwh kettle is boiling, the owl does not go up the 3kwh I would expect it to go up by.. Can anybody please explain why this is? If its so un-accurate I rather return it, as its pointless..

There's no way it's '50% inaccurate' IME. Check the installation again and make sure it's correct and if it is, I would contact the company direct. Phone number is 01635 556410

Magentasue

I've got a CurrentCost - new this week so bit early to tell much. When I turn most things off and just leave the fridge, freezer, boiler, phone and security light on, we're using about 100w. Of course, that may vary considerably over a period of time. As things get used, it seems as if we're using about 400w with laptops, router radio on.

Right now, we have TV, DVD, second TV, Xbox, two laptops and three or four lights on = 800watts. During the day, the display dances around as appliances get used but I don't take much notice. What I have noticed is that it recorded 13kw on a 'normal' day and 10 yesterday when we were out from mid morning until tea time. That seems right - we've been using an average of 13kw a day through the school holidays.

I've found it useful. After months of me nagging, the monitor has brought it home to the rest of the family how much we're wasting, for example, when all the lights get turned on as the teens go upstairs, and then come down leaving four lights on.

scope

loaner wrote: »

change the voltage setting if you want to make it more accurate

Its already set to 230v.

scope

loaner wrote: »

change the voltage setting if you want to make it more accurate.

re the half registering, try wrapping it around the other lead.

Changing it to the other lead made a difference.. the "normal" load went to 0.9kwh, and the fan heater now adds a further 2.5kwh to this number, so more what I expected..

Should I get a reading at all on the neutral lead? I've got two leads going to my fuse box, both giving me readings.

scope

I originally had it on the far right lead, as instructed in the manual, but there is nothing on the cables to indicate which is which.

JayMT

scope wrote: »

Its already set to 230v.

I wonder if your mains voltage is on average higher than 230V?

I've been doing some energy measurements today with a plug-in meter (Brennenstuhl PM230) and my voltage through the day has varied between 242-248V. On other days it has been as high as 252V sometimes! As I type now it's showing 241V.

Does the Efergy will allow you to enter your own voltage rather than a preset 230V?

It would be nice if these meters that measure your overall energy usage also measured the voltage as well as current to get a true power reading (like the little plug-in ones do) but I haven't found one yet that does. So it seems that the readings will always be an estimate at best, because of the wide variations allowed in the mains voltage (216.2-253V).

markbloke

Yes, the Efergy allows you to change the voltage in 10v steps. As mine is registering about 90% of actual use I've cranked it up to 250V and will check accuracy again. As a warning, I did this last night after drinking a fair bit of wine and accidently reset the meter losing months of data. Oh well.
:beer:

markbloke

I'm assuming the device works by indirectly measuring current flow. To calculate wattage it must multiply current by voltage. On that basis, to increase the calculated wattage I've increased the value assigned to the voltage.