Temporary High Power Usage

Veteransaver

Could be a pc turning on overnight for updates. Outside security light triggering on and not going off again
It was cold last night compared to previous 
Does it happen on cold nights? Something with frost protection maybe or a small heater plugged in somewhere
Does your fridge freezer have an auto defrost?

Gambler

On-the-coast said:

Well in order of probability here’s what could be happening. Most likely first:
1 something you’re unaware of is still using energy.  Eg Central heating pump.  Security system etc. 
2 your IHD has missed a few readings, then caught up everything in one hour.  I never trust my IHD - I go to the meter if I really want to see usage that can be trusted. 

3 your meter is reading incorrectly
4 weird stuff… inductive loads. Heat generating loads.  Any large coils of long extensions leading to Christmas lights?

No nothing at all like that.

QrizB said:

It's been like that since 0300 this morning.

It's turned colder again today, and dropped below freezing overnight in parts of the country. Is there a 300W frost heater somewhere that cut in when the temperature dropped?

No and the last time this happened was May!

Veteransaver

Does your IHD show roughly 300W on the current power screen? Surely just a case of finding out what is drawing that?

Gerry1

Try turning everything off at the consumer unit last thing at night.  Weather is cold so fridge and freezer should be OK if you don't open the doors.

Do you have any PIR floodlights?  Could be continually triggered by swaying branches in windy weather.

Ildhund

There's almost certainly something you've forgotten about that's drawing 300W somewhere, but the fact that it's switched on at two in the morning would suggest that something inanimate is doing that - a thermostat, for example. It shouldn't be too difficult to track down. I saw a case where something like this was happening while the house was empty and the family were all lying on a Spanish beach. That turned out to be underfloor heating in the conservatory where the temperature had dropped below its safety level. 

Gambler

Thanks all for your responses. I'll check when I get home later. From memory I think I can narrow it down to the kitchen sockets by turning off the fuse. Simply unplugging everything doesn't have the same effect.

Pretty standard kitchen with built in fridge freezer, washing machine, oven, hob, extractor, CH gas boiler. The only other thing is the sprinkler system in the cupboard under the sink. Mandatory in new houses in Wales.

I could try and get an electrician to call but by the time they are able to attend it will probably be back to normal.

Veteransaver

Gambler said:

Thanks all for your responses. I'll check when I get home later. From memory I think I can narrow it down to the kitchen sockets by turning off the fuse. Simply unplugging everything doesn't have the same effect.

Pretty standard kitchen with built in fridge freezer, washing machine, oven, hob, extractor, CH gas boiler. The only other thing is the sprinkler system in the cupboard under the sink. Mandatory in new houses in Wales.

I could try and get an electrician to call but by the time they are able to attend it will probably be back to normal.

It's not an HVAC system is it? Lots of new homes have them. Or a dehumidifier system kicking in.
300W is typical for a dehumidifier 

Veteransaver

Do you have any set top boxes? Eg sky boxes? 300W is too much for one but if you had several and they were all doing an update?
Does the 300W unknown power draw go on for many hours?

Gambler

Veteransaver said:

Do you have any set top boxes? Eg sky boxes? 300W is too much for one but if you had several and they were all doing an update?
Does the 300W unknown power draw go on for many hours?

Just a firestick which is turned off every night.

First incident started at midday last Christmas Day ! which lasted for 18 hours.

Then again 22-May 33 hours

Reed_Richards

A background of 0.03 kWh seems phenomenally good.  In my case it's typically between .15 and .20 kWh overnight when only the fridge, freezer and router are active.