Help me solve the mystery usage overnight for 3 months

Howdy ​@Bonney !

Everyone’s welcome here regardless of supplier, so hi! The name’s 186, Blastoise186 and I’m one of the Forum Volunteers around these parts. Just so ya know, we don’t work in the industry ourselves. :)

We’re definitely up for puzzle solving this one, but I could do with one more thing - could you grab a few snaps of your meter(s) and heating/hot water setup so we can see what you’ve got.

Thanks!

At a guess I’d say that you (accidentally?) had something on 24/7 rather than on the timer.

The daily use charts show it to be a regullar on/off throughout the day:

Regular on and offs like that are usuall indicative of a heater being switched on and off by a thermostat.

However you say that you don’t have a heater - Or do you?
Your main heating may not be electric but are there any small (portable) heaters about the property?
What else do you have on a timer that could have accidentally been switched to ‘ON’ rather than ‘Timer’?

Whatever it is it appears to be drawing about 1 kW when it’s running, which is typical for a portable heater.
We had a similar question recently where the culprit was identified to be a 1 kW patio heater that had accidentally been left switched on 24/7.
(Turned on when sat on the patio one chilly evening and forgot to turn it off again?)

So check for things like that, ie. garage, greenhouse, patio, etc. heaters.
Also check for heaters in bedrooms, one of those electric oil filled radiators left switched on 24/7 could show a use pattern similar to that above.
(Fairly constant on/off with a bit of extra usage showing at expected times such as 17:00 ie. tea-time).

The chart is showing half-hour buckets, so it’s more like a 2 kW draw, which really rules out things like freezers or circulation pumps. It’s almost certainly heating of some sort as you point out. 

Hey ​@Bonney, 

Welcome to the community! As ​@Blastoise186 has said we welcome members from all suppliers. We want everyone to feel welcome and to ask questions and learn from each other 😃

It appears you've received excellent guidance already. If you have time, providing photos of your heating system and meters would greatly assist our volunteers in tailoring their advice. Please don't hesitate to ask if anything is unclear

To me the axis is labled “kWh” and 0.5 kW used in 0.5 hour would still show as 1 kWh on that axis.

Or to put it another way a 1 kW heater would use 0.5 kWh in half an hour, that's still 1 kWh.

Did you perhaps misread 0.9 as 0.5? I don’t think I’m misreading 0.5 as 0.9 …
  

Will do. I should have said that this is a new build so have a brand new combo boiler and smart meter. Heating is programmed to come on at set times twice per day and not at the intervals shown. I’ve also never had heating kick in and run all night  like some of the examples shown!

there are no additional electrical devices for heating or water.

As per my other reply I only have a combo boiler for heating and hot water and it’s on a schedule.

no other plug in items bar the usual household items.

i do have external plugs - can they be causing any issues?

​@Firedog -
it's done my head in a few times on such graphs,  they actually show kWh/time.

And of course kWh/h is just kW.

Normally it would be relatively obvious to target heating devices for that usage, but if you really aren’t sure, how about waiting for it to be active and then turn each breaker off until it stops. That would at least point to a specific circuit.

Hey ​@Bonney,

Are you any further forward with identifying what’s causing the issue? ​@oho has made a great recommendation above that you could try.

Let us know how you’re getting on!