Unexplained half-hourly usage pattern

​@rogerp64 13000kwh electricity over a year is incredibly high, and we rarely see this sort of usage, especially in a property like you’re describing. Are the bills incredibly high at the moment? If not, then this figure of 13000kwh will be incorrectly labelled on our systems, rather than there being a problem within the property causing high usage.

If your mother had gas heating then that amount of kWh would not be that unreasonable. However, 13000 kWh of electricity must be very expensive.

Can you post a graph of her usage over a year?

​@rogerp64 

What you report seems so odd, the zero readings overnight particularly, that I’m wondering if we may possibly be looking at a “crossed meter” situation here?

If you notice that the meter details and readings on your bill don’t match the meter that you think is yours, or you notice that your meter isn’t clocking when you think it should be, then you may have crossed meters.

There is more information about what a crossed meter is, and how to do a ‘kettle test’ to check for it, here:

That’s a very good point that I hadn’t considered. ‘Everything off overnight’ could be a ‘communal’ supply, e.g. powering washing machines and lights in a basement. I think someone would have noticed if, say, both fridge and freezer were off overnight. The usage pattern shown in the screenshots can’t really be that of a household. 

Thank you everyone for your comments.

Clearly there is something wrong and based on this image, it looks very much like something happened in May 2025 !!

Consider though that not every houshold necessarily has a fridge or a freezer.

It might be considered unusual these days, but it’s not unknown.
(I lived from 2000 to 2011 without either, it’s easy to do when the shops are nearby, and even if not there’s always canned food, etc.).

​@Firedog ​@Nukecad Mum has a side-by-side Fridge Freezer.. it doesn’t go off overnight…  she is generally awake watching TV, making cups of tea, fan heaters on until 4:00 or 5:00 each night.. she then sleeps in till around midday.

I found an email from 2021 SWALEC…  showing project usage and cost. I appreciate everything has increased in price, but my Mum’s pattern of behaviour has not changed.

(earlier comment regarding communal meters.  Mum is in a fully detatched home)

Mum has a pretty big side-by-side… She is awake most nights until 4:00 or 5:00am watching TV, boiling the kettle and with the fan heaters on…  so this zero usage at night just cannot be right.

The usage figures you shared this morning are interesting, too. The monthly figures are derived from meter readings, not half-hourly usage data. Here are a couple more questions:

1. We can’t tell whether the figure of 48.98 in April 2025 is for the whole month or just part of it. Which period does the entry cover?
2. Was this meter newly installed in April 2025? If not, why are there no entries before then?
3. On the meter readings page, you should see the serial number (the MSN) for the meter concerned. This should match both the number printed on the front of the meter itself and, of course, the number shown on bills. Does it? 
4. It’s a dreary exercise, but could you please look at the meter reading history back to March-April 2025? There will be lots of clicks on Show more required.
   Every entry should be labelled Smart - are they?
   Is there anything odd about the sequence of readings for April and May?