MrsIHN submitted our meter reading this morning, and they flashed up a “are you sure, that seems like an awful lot” message at her. Turns out the were right, in the past month we seem to have use A LOT of electricity. I think our estimated typical usage, based on the last twelve months is 90kWh, and we’ve used something like 300kWh.

There’s only two of us, we have solar panels which have started producing a bit now we’re getting into sunnier days, we’ve been running things like the dishwasher/washing machine in the day in order to use the solar juice where possible, so it’s all a bit baffling (not to mention eye-wateringly expensive).

Things that have changed in/around the period in question:

– we’ve had a new consumer unit fitted (straight swap)
– we’ve had a new range cooker installed, but it’s used about the same amount as the old one
– I’ve been running a 200W rated sander quite a lot to strip paint of a gate. Maybe about 12 hours running in total

Now, I can see how the final two could use some more juice, but not three times as much as we’d normally use. The first should have made no impact (unless he’s really screwed up?)

So, any ideas of what to check? We only have a very dumb meter.

Are going from meter reading to meter reading or have there been estimates used in your billing? If estimates have been used then this could just be a correction.

Pretty sure it’s reading to reading.

You don’t have underfloor heating that might have been switched on do you?

Nope. We have an electric immersion on the water tank, but that only runs when the solar is pumping power back into the grid (it’s on an iSolar thing)

We have an electric immersion on the water tank, but that only runs when the solar is pumping power back into the grid (it’s on an iSolar thing)

The iSolar thing will have a clamp which goes around your electricity supply to measure export from the panels and then divert that power to your immersion heater.

It’s not that obvious which way around they go and it’s possible that it’s been clipped on backwards after your consumer unit change, which means that your immersion heater runs when you’re actually drawing power from the grid.

This is the first thing I’d check (the CT clamp may be next to your main fuse, or in the consumer unit, or on the wiring from your panels somewhere).

90Kwh/month seems insanely low!!

which means that your immersion heater runs when you’re actually drawing power from the grid.

This is the first thing I’d check

This was a thought I’d had, and I have checked it quickly, and it’s only running when the sun’s shining (today is a good example, it’s kicking in when the sun comes out and not when the clouds come over). I’ll double check the clamp though, you never know, but I don’t think he even touched it given where it is physically in relation to the consumer unit.

90Kwh/month seems insanely low!!

I may have the number wrong, but we’ve used a lot more this month than last month whatever.

Misread the meter. I did this last time and woke up to a £2k bill this month. All resolved now and a smart meter getting fitted next month.

Misread the meter.

Nope, we’ve both checked and rechecked. Of course, it could have been a misread on a previous reading I suppose.

I may have the number wrong, but we’ve used a lot more this month than last month whatever.

it’s certainly strange!
We’re down to about 6kwh/day (over the last 10 days) and that’s with solar PV heating the water so no boiler pumps running.

Take daily readings – preferably last thing at night and first thing in the morning to see where the usage is during each 24hrs.
If you have a 4Kw solar array you should be using very little between 9am-6pm
I found that our house uses nearly 3Kwh overnight on “stuff”!!
(big fridge freezer, mesh wifi, multiple sonos, etc.)

I’m not sure that all solar immersion diverters are equal and there is a possibility of power being imported – but not to that level.

90 kwh per month on elec sounds very low .

300kwh per month is about what we use per month – 3 people – gas CH/Boiler – so elec is only used to run lights (all led) ,tv,fridge, computer, wifi, dishwasher etc

Take daily readings – preferably last thing at night and first thing in the morning to see where the usage is during each 24hrs.

Yeah, we’re going to start doing that. And, on that subject, any recommendations for usage monitors in the absence of a smart meter (and we’ve contacted the electricity company about getting a smart meter)? I was looking at stuff like this:

https://www.ebay.co.uk/itm/203964182453?hash=item2f7d366fb5:g:6w0AAOSwBBtii7yM

Try turning everything off and check meter is not moving.

Also hourly consumption profile if poss, should id the culprit.

My immediate thought was immersion, but you’ve solar so would it be possible that the meter is reporting energy going *out* to the grid as usage?

Anyway, smart meters let you see minute-by-minute usage which is great for identifying power sinks, but there’s usually quite a waiting list for those. However, traditional clamp-based monitors are fairly cheap and just as useful.

We used to have one of these https://efergy.com/elite-classic: clamp around the main cable going into the consumer unit, and then the monitor connects wirelessly and shows your current usage. You can then see how much is being used, turn off entire circuits in the to work out where the problem is, etc. Although I will say you can get obsessed with reducing the ‘idle’ usage…

As you’ve solar it’s probably worth either investing in a better model than the Classic which can handle solar readings too and show you charts over time, or see if your provider can get a proper smart meter installed quickly.

Right, I’ve just checked the numbers with MrsIHN. In our previous ‘worst’ month, so depths of winter, solar doing sod all, lights on, oil heater on in office, we used 300kWh. Last month, which saw the solar kicking in reasonably, no oil heater use, and we were actually away for a week, we used 1200kWh. I mean, WTAF?

I’ve double-checked the iSolar immersion stuff, and it’s definitely only kicking in when the sun’s out.

Is there any way a consumer unit swap could have led to this? I’m going to get the fella back, if only to try and work out what’s drawing what, but I’d like to be slightly forearmed with some knowledge of any mistakes he might have made.

Fault on the solar?

I’m wondering if your meter is faulty and counting your solar export as import. You should have a second meter for your solar generation – what’s that saying?

7kW average (which is what 1200kWh in the space of a week gives you) should be sufficient to make the supply cable into your meter noticeably warm to the touch.

Is the meter showing how much you have exported rather than imported (just a wild guess..)?

Fuse board change won’t make a difference, there’s nothing in them that has a current usage. Unless you had AFDDs fitted as the processor in them uses about 1 watt a day. In domestic settings the biggest draw is if you’re trying to change the temperature of something, so check the solar tail clamp, there will be a direction arrow on it, and if you can turn the immersion off for a bit

(which is what 1200kWh in the space of a week gives you)

Sorry, just to be clear, the 300kWh/1200kWh figurers are monthly.

You should have a second meter for your solar generation – what’s that saying?

We have, I’ll check

Something’s very wrong there!!

Is there any way a consumer unit swap could have led to this?

Possibly but I’ve no idea what!

When the solar was installed at our other place the moron wired it so that the solar generation was fed into the incoming side of the meter (rather than into the CU) …. so we were paying for electricity that WE had produce ourselves!!

This is not the case with yours as your diverter wouldn’t be kicking in – it would always be waiting for enough generation from the panels.

I’m wondering if your meter is faulty and counting your solar export as import.

Follow the cable from the inverter – it should go either into the CU or into the ‘inside’ of the meter, not the ‘outside’.
If the meter is digital it should be intermittently showing a ‘rEd’ message when there is power being exported to the grid. This can be checked by switching off the immersion while it’s sunny and watching the meter.

if it’s not showing the message when you’re def generating more than is being used then the meter is faulty.

Do you have neighbours ‘attached’?

Sounds like your export is getting tallied on the meter as import (no, I don’t know how either :D)

The easiest way to check this I can think of is to watch your meter on a sunny day, make sure you’re only running a base load in the house (no washing machines, dishwashers, ovens running). Watch the meter for a few minutes so you can monitor how quickly the tenths, hundredths etc are racking up then isolate the solar system (no, not that one) and see if it stops.

If the meter is digital it should be intermittently showing a ‘rEd’ message when there is power being exported to the grid.

It is showing that message

Follow the cable from the inverter – it should go either into the CU or into the ‘inside’ of the meter, not the ‘outside’.

I’ll double check this, but don’t believe any of it was touched during the CU swap (and the rEd message suggests it’s all the right way around anyway, doesn’t it?)

Do you have neighbours ‘attached’?

We do, in an old pair of houses, with possibly some interesting wiring. We’ve got a nagging feeling that maybe the sparky reconnected an old circuit that was going next door or something?

Watch the meter for a few minutes so you can monitor how quickly the tenths, hundredths etc are racking up then isolate the solar system (no, not that one) and see if it stops.

Irritatingly, it only shows whole units, but yeah, this could be something to try

Is the meter showing how much you have exported rather than imported (just a wild guess..)?

Rockhopper makes a very good point! Difference between import and export might be as little as an arrow or the letters I/E.

(and the rEd message suggests it’s all the right way around anyway, doesn’t it?)

Yes it does.
rEd mean ‘reverse energy detected’ – so the meter’s working fine.

Is the meter showing how much you have exported rather than imported (just a wild guess..)?

It’s a dumb meter so it will only show power in one direction. So the meter near the CU will show the imported power and the separate meter near the inverter will show the total generated (not exported… because how would it know how much of your own generation you’ve used?!)

Right, so then, after logging all the previous readings and dates into a spreadsheet and looking at the pattern of usage, we think what’s happened is that MrsIHN possibly misread/mistyped a previous reading, so it was 1000kWh lower than it should have been and that reading was for a 3 month period. The latest one is correct, and is only a month after the previous one, so that ‘missing’ 1000kWh is all showing in this month. We’re going to keep monitoring to make sure, but panic averted.

No help at all on this but interested to see the outcome….

… as usual, human error!

(although it does show you just how much you really are using)

I’ve learnt that there are clip on smart meters.
Why did no one tell me before?

I’ve learnt that there are clip on smart meters.
Why did no one tell me before?

They are not very good, I had one once and couldn’t get it to work at all.

Interested in this, we’ve just built a new house with 6.4kw solar array, ashp, I work from home in Separate office, lots of clothes washing etc, currently at 3865kw from start of year!

No help at all on this but interested to see the outcome….

Spoiler alert – he threw the wife under the bus, he didn’t read the meter, she did and in fact he didn’t even know she was reading it and if he had known she was reading it then of course he’d of put a stop to it and she must of borrowed his phone to take the pictures of the meter because he doesn’t even know where the meter is or what it does and is at a loss as to how the photos of something he doesn’t recognise got on his phone. 🙂

It’s like you were there 🙂

Well, the plot thickens…

We’re now checking the meter fairly obsessively, and overnight, from about ten last night to half six this morning, we used 12kWh. That seems pretty nuts, doesn’t it? We were in bed the whole time.

We’re going to start process-of-eliminating what might be using it, but I have a question about the solar panels. I’m aware, from looking at solar for the campervan, that there can be an issue where the panels actually draw power when it’s dark, but I assume that on a domestic array this would be pretty rare unless somethings gone very wrong? I’m going to isolate them overnight tonight anyway, just to see, but I think that’s clutching at straws, right?

We’re now checking the meter fairly obsessively, and overnight, from about ten last night to half six this morning, we used 12kWh. That seems pretty nuts, doesn’t it? We were in bed the whole time.

I have not heard of that potential fault with solar panels – it seems very unlikely.

Otherwise, the only normal way to consume that amount of electricity would be electric heating. As suggested above – do you have any underfloor heating or an electric towel rail?

As suggested above – do you have any underfloor heating or an electric towel rail?

There is a panel heater in a little hallway, that’s really only there to stave off damp, comes on when the temp hits 11deg, goes off at 17deg. It’s only rated at 400W though, so even if it was running all day that’s only [maths…] 9.6kWh.

We’re now checking the meter fairly obsessively, and overnight, from about ten last night to half six this morning, we used 12kWh. That seems pretty nuts, doesn’t it?

Yes it does!
Our house used 2.2Kwh between 11pm and 8am.
That’s running a fairly large fridge freezer, mesh wifi, 2 x TV on standby, 7 sonos speakers, a hardware firewall, 3 x Raspberry Pi’s, the Solar PV inverter my PC in sleep mode and a smallish UPS.

I’m aware, from looking at solar for the campervan, that there can be an issue where the panels actually draw power when it’s dark

Pretty positive that there’s a thing to stop this built into the inverter.

I’m going to isolate them overnight tonight anyway, just to see, but I think that’s clutching at straws, right?

Probably but it’s certainly worth isolating the PV (there should be a big isolator near the inverter) just to eliminate it.
Switch off the immersion overnight also.

Just a thought….. your Solar diverter doesn’t have the option for an automatic ‘boost’ does it?
(My Immersun does – I can set it to boost the hot water at a certain time)

As suggested above – do you have any underfloor heating or an electric towel rail?

A towel rail will only draw about 400w or less. 10sqm of electric underfloor is about 1kw I think but if it was on all night you’d certainly know about it when you walked on it!

IHN: looked in the loft recently?!

lots of stuf runs overnight, and most is not switxhed off.

fridge / freezer
TV
PVR
Microwave
Internet router
mesh wifi points
some radios still draw power when not running
alarm clocks
house alarm
trhe clock in the cooker

not sure that any of those would be massive though…