Why is my energy usage so high when I'm not at home?

System

This discussion was created from comments split from: How much power does your house use when nobody's home?.

Ron_Weasley

I came to this thread concerned about my reported electricity usage.

On Sunday the house was empty and yet EDF tells me I used 9 kWh that day!?!?  That's nearly 400 watts x 24 hours. Ok I have a new fridge-freezer in the house and another new one in the garage. I am told a fridge freezer uses between 200 and 500 kWh per year, so let's be generous and say 2 kWh per day each.

The rest of the house contains only 3 TVs on standby, a router and 3 Google smart speakers. Add the central heating pump and fan in the condensing boiler.

But how on earth do I get to 9 kWh???

I am seriously concerned if the meter is miscalibrated.

MattMattMattUK

Ron_Weasley said:

I came to this thread concerned about my reported electricity usage.

On Sunday the house was empty and yet EDF tells me I used 9 kWh that day!?!?  That's nearly 400 watts x 24 hours. Ok I have a new fridge-freezer in the house and another new one in the garage. I am told a fridge freezer uses between 200 and 500 kWh per year, so let's be generous and say 2 kWh per day each.

The rest of the house contains only 3 TVs on standby, a router and 3 Google smart speakers. Add the central heating pump and fan in the condensing boiler.

But how on earth do I get to 9 kWh???

Immersion heater left on, fridge door left ajar, TV left on that went into sleep mode after a period of time. See what happens over a few other empty days, but unless it is a pattern I Would not be concerned. 

If your meter is smart you can look at the half hourly data to see when the actual usage occurred. 

Ron_Weasley said:

I am seriously concerned if the meter is miscalibrated.

That would be a long way down the list of likely reasons and an odd thing to jump to straight away.

victor2

You've revived a very old thread, but the regular advice on here is to try @Gerry1 's Meter Sanity Test, and see if you can explain the usage. If you still have issues with it, better to start a new thread.

MSE_ForumTeam5

We've split this into its own thread

QrizB

Ron_Weasley said:

But how on earth do I get to 9 kWh???

How much electricity do you use on a normal day, when you're at home, at this time of year?

Do you have half-hourly readings for the day? (If not, go into your EDF account and switch them on.) Your half-hourly readings will let you (and us) see whether it's a steady 3-400 watt drain or more variable. For example, if your house used 3kW for a couple of hours, it might indicate an immersion heater cutting in.

Ron_Weasley said:

I am seriously concerned if the meter is miscalibrated.

That's a long way down the list of possibilities.
You'll need to eliminate all the more likely options first, before thinking there's any reason to blame the meter.

Grumpy_chap

Ron_Weasley said:

On Sunday the house was empty and yet EDF tells me I used 9 kWh that day!?!?  

But how on earth do I get to 9 kWh???

You need to look at the detail graphs that EDF provide.

My house was empty on Sunday and used 6.6 kWh:


Each line is energy used over half hour period.  So, I have a base-load of 0.2 kW overnight.  (0.1 kWh for half hour so 0.2 kWh for a full hour).  That base load will be rooter, Alexa, alarm, CCTV, TV on standby, phones on standby etc.

We had the heating and hot water off so no contribution from pumps etc.

The spike at 10 pm is almost certainly the fridge freezer.  I suspect also the two higher periods at 05:30 and 6 am are the fridge freezer but the load happening over two-half hour periods rather than within a half-hour period.

The increased base-load from 7 am (daytime) will be the Christmas decoration lights switching on.

The dip in the late afternoon is because I have set some devices to switch off 4 pm to 7 pm (as we are trying to maximise the "free" electricity earned for Sunday Saver time-shifting).

After 7 pm, the Christmas decoration lights plus the household security lights switch on so a bit higher in the evening than through the day.  Not much because the household lights are energy efficient while the Christmas Decorations are not.  

Then lights switch off gradually from bedtime until "all off" at midnight.

That's my house on an empty, mild Sunday in December.

Can you look at your half-hour data and assess in a similar way to help understand the 9 kWh used?  It is not that outrageous and you may see an obvious left on all the time demand, perhaps a heater somewhere, or extra lights...

Gerry1

MattMattMattUK said:

Ron_Weasley said:

I came to this thread concerned about my reported electricity usage.

On Sunday the house was empty and yet EDF tells me I used 9 kWh that day!?!?  That's nearly 400 watts x 24 hours. Ok I have a new fridge-freezer in the house and another new one in the garage. I am told a fridge freezer uses between 200 and 500 kWh per year, so let's be generous and say 2 kWh per day each.

The rest of the house contains only 3 TVs on standby, a router and 3 Google smart speakers. Add the central heating pump and fan in the condensing boiler.

But how on earth do I get to 9 kWh???

Immersion heater left on, fridge door left ajar, TV left on that went into sleep mode after a period of time. See what happens over a few other empty days, but unless it is a pattern I Would not be concerned. 

If your meter is smart you can look at the half hourly data to see when the actual usage occurred. 

Ron_Weasley said:

I am seriously concerned if the meter is miscalibrated.

That would be a long way down the list of likely reasons and an odd thing to jump to straight away.

Do the Meter Sanity Test to rule out the most common problems.  Then do the metrology (flashing light) test again as if the house were unoccupied.  You'll probably find there are quite a number of 'vampire' loads that can add up to a surprisingly high background usage.  Switch off circuits in turn at the consumer unit to track down the culprit(s).

Scot_39

Its easy to look at a number like 9kWh - and think it must be big loads - but in reality lots of small loads - also add up - including certainly older devices like halogen spots in fancy kitchens, TVs - left mains connected on standby etc.

A common "large" draw culprit being a HW tank immersion heater - in homes with HW tanks - taking over from the GCH to heat water used - which would seldom kick in whilst gas boiler heating left on.

Other lower power sources - frost heaters (we had 2 (c60-80W) 1 under our cold water tank in loft and 1 under the units in kitchen to protect pipes at parents house) - security lights (old halogen upto 500W each etc).

Halogen spot lights in modern kitchens another classic -  sister had about 14 in kitchen diner (ceilings, under top cabinets etc) - 20W and 50W - added up to around 0.5 kW - all now LED pulling a fraction of that.

How many lights did you leave on - if any - and types ?

But as you point out your only looking at maybe 7-7.5kWh after 2 new so assume healthy FF subtracted - or c300W ave load - and know several things on standby that you have listed - you might be surprised how much is explainable by just your list of small loads.

Not sure about the smart speakers - but older smart TVS with wake on voice etc can pull 10W plus in standby - 0.24kWh a day.  Games consoles etc higher, PCs etc.  

Wifi routers can be 5-10W similar - wireless on higher than off - so you can even hit that button if out all day.  

Your smart speakers might be pulling 5-10W each - possibly a bit more - wifi and processor (just checked a small nest one - it has 30W rated power adapter).

Assuming you have an IHD - look at your base load - and then go around the house switching those 3 tvs and 3 smart speakers off at the mains - and see how that base load changes.

Your GCH pump - if left heating on for any of that day - could be consuming 50-150W for hours during the day - depending on model and house size.

At a push you could fit something like tapo110s iirc - smart plugs with individual measurement to some of the devices fed by normal sockets.

But the best thing if got a smart meter - is as above - use suppliers site or an app like bright or loop to interrogate 1/2 hourly data - to see if constant or one or more large loads triggering for a couple of hours on and off on the day.

And do an audit of all of those devices you think are trivial you had left on standby - you might be surprised - and you may even have forgotten a few - ovens, microwaves, lights - home and security etc - but can easily see upwards of 100W potential. 

You could probably even switch the freezers off for several hours without any harm coming to food - if that is you remember to leave the doors closed - or fit tapo type device with monitoring if suspect a problem.

Your IHD likely gives you the last n days of use - mine does 8 days, last 5 weeks, last 13 months.  You might have had other part empty days with Xmas and New Year celebrations recently to compare.

Last time left home empty - for days (so even my router, IHD and microwave / oven clock goes off) - in Sep - so no HW or heating used - my current 2 bed all electric home used 1.2-1.3kWh daily - thats just 1 small modern FF, 2 led bulbs one on an evening timer, one 24/7, mains burglar/2 smoke alarms etc and of course the wiring itself.

My power use on IHD goes as low as  20-30W without anything like even a single light on - just the router, alarms, clocks etc as above - in house during the day / night.  What is your typical minimum displayed ?

Leave my desktop PCs, NAS drives, TV, Bluray/DVD/Recorder on standby - that jumps to 50-60W - adding towards 1kWh per day.

debitcardmayhem

@Scot_39 tsk, don’t leave pcs on standby but hibernate 

Scot_39

I switch them off at the mains when done - I don't tend to leave on standby these days - after seeing power draw on IHD after smart upgrade.