Elec Meter readings massively higher than energy monitor readings

verylittlecarrot

Hello, I'm a first time poster, so please bear with me as I find my feet!

We have been in our home for 3 years, and our electricity consumption seemed excessively high, in fact we began to doubt the meter accuracy. We received an energy monitor from British Gas, and it tells us we are averaging 12- 14 kWh a day. The actual meter has us at 20-24 kWh a day. We ask BG to test the meter, and they duly remove and replace it with a new meter, then decide they will not test it, but will instead compare general consumption between the two meters over a period of time. The new meter also has us at 20+ kWh a day like the old one. And yet, the energy monitor says we averaged 12.5 /day over the last month.

Of course, the energy monitor may be wrong. We are going to replace the electricity monitor to see if this is the culprit, but if we see similar readings from a replacement monitor - what can we do next? BG seem convinced their meters are fine, but can't give a reason as to why the electricity monitor differs so hugely.

Consumer direct suggested that, if the monitor is correct, then possible causes are that the meter may not be earthed properly, or that we may have have 'seepage' of electricity, which would account for the discrepancy.

Has anyone had experience of something similar? I'm at a bit of a loss as to what to do next.

Thanks!

lowbrim

I would turn everything off if possible for an hour. If electricity meter still shows usage but monitor shows nothing then there is a problem.

Another option is to get an appliance with a known usage such as a 1 kw electric fire, kettle 3kw etc and see if your monitor increases by 1 kw or 3kw if it increases by something less then you know the monitor is reading low.

Having had a replacement meter I would be surprised if both meters are wrong but you never know. I must say that 20kw/day is quite a lot of electricity unless you are using it for heating or have a large house with normal bulbs rather than energy saving bulbs.

dunloadin

If it's saying your 'averaging' less than you used could it be that it's just using the load you are using at the time your looking at it to calculate the daily use? If so switch the kettle on then see what it's averaging then....expect to be traumatised at the result!

Electricity meters arn't earthed, so take that suggestion with a pinch of salt!

There will always be a discrepancy between meter/monitor, but check that your monitor is set for KWh. Also make sure it's clipped onto the correct cable. If you have a single rate meter it should be on the live out (cable on the RH side of the meter)

Do you have Eco7...if so you will probably not be recording all the usage....to get the total used clip the cable on the LH side.

chris1973

Energy Meters are not calibrated pieces of equipment, they are cheap measuring devices made in bulk out in China for around a fiver a throw - wholesale. They confirm to no tolerance approvals and have no calibration certification with them.

Open them up and you'll find bog standard 5% resistors and capacitors with +/-20% swings. Open up a more specialised piece of measuring equipment such as a professional clamp meter and you'll find a far higher quality and close precision components and there is a reason for this.

In short, domestic wireless energy monitors are not the holy grail of precision instruments and I personally consider them little more than stocking fillers with limited novelty value. Yes they will show you when things are 'on', but their readings should probably not be taken over and above what an electricity meter records and certainly not what two installed electricity meters are both independantly recording!.

The main problem i've encountered with the ones i've come across is the 'run on' which i've witnessed. Most of these devices rely on a wireless signal to update the unit from the sensing 'clamp' fitted to the meter tail, unfortunately in order to get approval in the UK and Europe these monitors share a type approved radio spectrum frequency which is also occupied with other 'domestic' wireless equipment, ranging from doorbells, car keyfobs to baby listeners, and sometimes this crowded frequency results in the signal integrity between the meter clamp and actual monitor to become less than reliable, of course, even range can of course be a factor.

I've often seen appliances switch off, yet the energy monitor meter has not updated itself to take into consideration that the current is no longer being drawn, sometimes this phantom over-run can last five or more minutes before the meter finally updates itself. Where an appliance is one of high consumption such as an heater or immersion or Electric Oven, this can result in high phantom readings being recorded on the Energy Meter display for far longer periods than were factual.

This means that although the appliance has switched off some five minutes ago, the meter continues to act as if it is still being drawn, and so continues to calculate consumption cost which doesn't exist, therefore over a period of time it will indicate a much higher consumption than has actually been drawn, giving higher accumulated costs.

The same can also be said for under reading, a device may switch on, but the meter not be updated to monitor and record its consumption, again if its a high current device(s), it may easily 'miss' several KW/H worth over the space of 24 hours.

Another flaw with these monitors, is that some appliances like washing machines draw short bursts of current, such as differing RPM's and have wash cycles where the motor is running in small bursts or is varying its speed, its extremely unlikely that a basic wireless energy monitor will update and refresh fast enough to take into consideration this type of ever changing consumption.

I think the chances of two, calibrated DNO supplied and installed Electricity Meters both being wrong would be extremely rare, especially as they are both recording exactly the same figures!. For two calibrated meters to 'fail' by exactly the same degree as to record identical readings would be virtually impossible.

My money rides on the fact that you've bought far too much into the ramblings of others promoting these energy monitors, and see before you a true reflection of just how inaccurate they can sometimes be.

So I would be looking at ways of reducing your consumption, rather than chasing phantoms.

Brian99_2

Best way to test is to put EVERYTHING off for a while (including fridge , immersion heater, lights, wee chargers) and use JUST a 1 kw fire for an hour.

The the meter should move on by 1 kWh. Hopefully you'll find the meter isnt far wrong

soxxxxy

I would suggest you get an electrician round to test all appliances and mains,may cost you abit but could save you money in the long run,and they should fix it if they find a fault.I have to say i do agree with Chris1973 energy monitors are really only a guide.Can i ask how old the wiring is in your house?

chris1973

The the meter should move on by 1 kWh. Hopefully you'll find the meter isnt far wrong

I think the empathsis is on Meters - (s)he currently has had two installed by the DNO, and the new one is recording exactly the same consumption as the old one did. As I said before the chances of two electricity board meters being incorrect and faulty by exactly the same degree would be virtually impossible. Certainly if they do both turn out to be faulty, i'd be putting some lottery numbers on tomorrow......

I must say that 20kw/day is quite a lot of electricity

Not really, my storage heaters combine to use 55 KW / Night its just a matter of scale and the household and depends what is running. A 2KW convector heating running all day in a badly insulated conservatory / bedroom etc in winter, will use close to that 20kwh figure all by itself.

I'd be looking at how many rooms use those little recessed halogen downlighters - several of these in a room can use upto 350W of consumption compared to the Olde Worlde (now banned) 100W conventional light bulb they probably have been fitted to replace!. I've seen some new build houses or homes where new kitchens and bathrooms, hallways, stairways and bedrooms are full of these nasty bill hogging things. You'd also be surprised at how many people still use those older halogen uplighters, often fitted with 200W / 300W linear R7's - the same as you get in outdoor floodlights.

Many people are quick to blame heating or a forgotten immersion heater for high bills but overlook the fact that during darker nights and days, lights in rooms are on for longer, especially at weekends, lights on stairs, kitchens, landings can be left on all evening, especially in large family households with kids. If you happen to have 2 rooms and say a landing fitted with 35W / 50W downlights, it can easily all combine and add up to 1KW, and running between say 4PM and 11PM - thats easily several units per day just in lighting consumption.

Then add 2 or 3 large screen TV's, Xboxes, PC's etc (because most kids will each have one of these, and if you have 2 or 3 kids...) so thats approaching another 1KW just in entertainment devices.

Also look at how often the washing machine, tumble dryer, dishwasher is used. Do you cook by Electric or Gas?.

Also are there any outdoor PIR floodlights being triggered by the wind / prowling cats etc when you are asleep?

Things do add up, even the mundane usage ones especially in multiples such as in instances where the whole family is at home and indoors with 2 or 3 rooms constantly occupied and everybody watching different programs on different TV's etc, and so they certainly shouldn't be overlooked.

soxxxxy

Oh and dont forget the shower Chris,i think my meter throws a hissy fit when my DD goes in there for half an hour at time !!!!!

chris1973

soxxxxy wrote: »

Oh and dont forget the shower Chris,i think my meter throws a hissy fit when my DD goes in there for half an hour at time !!!!!

Ouch!, yes an average 9.5KW shower will use nearly 10 units per hour, thats about 1 KW/H (1 electricity unit) for every 6 minutes its running!.

Get an electrician to fit a timer, or better still switch it off at the RCD after 3 minutes and listen for the cold water screams :eek:

(I'm joking - dont go randomly throwing high current carrying RCD's for fun )

soxxxxy

I am so glad she is at uni now my energy consumption has definitely gone down over the last couple of months lol ( i do miss her really bless ).

verylittlecarrot

Thank you all for your kind responses. To answer some of the questions raised; we don't really use the electricity for heating much (with the exception of the immersion heater for just a few weeks over the summer when the LPG aga is off). We no longer use an electric kettle, we use the aga. No electric shower either, the aga heats the water. The electricity is for lighting, fridge, one new fairly low consumption tv, laptop etc.

The energy monitor calculates total consumption over 7 days and 30 days; I calculated the mean daily consumption from that.

I do accept that monitors are not accurate, but I'm not convinced yet that the enormity of the discrepancy is that easily explained. The meter is measuring almost DOUBLE the monitor, and this is over long periods. Does anyone think there is another possible technical explanation for a meter capturing twice what the monitor does?

If a replacement monitor matches the meter I will happily accept this is a problem with the monitor under-counting. However if we see the same readings I need an explanation for what is happening.

I also understand that two meters saying the same thing looks pretty compelling, but I suppose I'm still unconvinced. I'm looking for theories, however improbable, that I can explore. Perhaps the meters are both fine, but there is some issue with the way they have been wired. Could they be double counting?!! I have no idea.

I'd welcome an electrician's suggestions - I think that may be my next port of call.