• We invite you to join UKWorkshop.
    Members can turn off viewing Ads!

weird electricity consumption.

UKworkshop.co.uk

Help Support UKworkshop.co.uk:

Phil Pascoe

Established Member
UKW Supporter
Joined
29 Jan 2012
Messages
22,001
Reaction score
2,077
Location
Shaft City, Mid Cornish Desert
I have economy 7. The biggest power consumption by a mile is the immersion heater (we have no mains gas). This is set to come on at night (the reason for e7) on an electronic timer. This has a warning light as does the isolating switch nearer the tank, and both come on at night when the tank is heated. There is no question that it is not heated by day. Probably 70% of the use of the washing machine and dishwasher is at night. The main daytime use is the cooker (not everyday and for an hour max), a microwave, a kettle, an aquarium, a couple of computers (all day), a TV in the evenings and any lighting which is all led. Fridges and freezers run all the time. I checked my bill carefully for the first time and I'm using two and a half times the electricity in the daytime as the night. The number one reading is definitely the night reading, and this is the smaller usage.
 

Spectric

Established Member
UKW Supporter
Joined
19 Feb 2015
Messages
2,663
Reaction score
1,211
Location
North Cumbria
Your immersion is around 3Kw and therefore three units per hour, how long it stays on depends on the size of the tank, it's initial temperature and the setpoint but should not be on all night. Washing machines now only use cold water feed so will not draw down on the hot water and the same for dishwashers so I assume you have no overnight consumption of hot water. I would say that using more electricity during the day is more than possible, a kettle is around 2500 watts, cookers can also consume and everything else adds up and this time of year you have a lot more lights on, you should fit LED bulbs. Econ 7 was originally devised for electric storage heating where it works ok to a point.
 

D_W

Established Member
Joined
24 Aug 2015
Messages
8,122
Reaction score
1,377
Location
PA, US
Easiest thing to do (assuming you have a smart meter and the consumption is accurate and not calculated as highest rate measured at points, etc) is to start varying consumption of things that use electricity.

Also, point of use is easier to measure if you can get a gadget that shows what things are using.

As an example, I have a "1800 watt" rated toaster oven. It's from china, so no surprise that it uses 1150 watts.

Also have a vitamix that claims 11.5 amps at 120V. When it's working on a drink at high speed, it will draw over 2000 watts and gradually work its way down to 1600 (still above its rating) as the drink gets easier. I always wondered why the plug would get a little warm (almost certainly voltage drop).

700 watt setting on the space heater actually draws 1000 continuously as long as it's running.
 

Myfordman

AKA 9Fingers
Joined
19 Jan 2013
Messages
2,458
Reaction score
192
Location
Southampton area
What is the ratio on previous years bills. As you have only just started looking in detail, you possibly have no idea what to expect.
If your consumption is in the proportions you say then E7 is the wrong tariff for you as the day rate is higher on the assumption that most of your consumption is at night
 

flh801978

Established Member
Joined
21 Dec 2008
Messages
1,409
Reaction score
81
Location
Sheffield uk
So are you using 35 units in a 24 hour period? So perhaps £7 a day if all at day rate £5.50 with 10kw at night rate?
That doesn’t sound too bad to be honest
Try reading the meter during the day and again after 2 hours see how much you have used?
 

Spectric

Established Member
UKW Supporter
Joined
19 Feb 2015
Messages
2,663
Reaction score
1,211
Location
North Cumbria
Another way is to go back to basic physic's and work out the energy required to raise the water temperature from a to b.

Say your tank is 200 litres and is at 30°C and you want it 60°C.

200 x 4 x ( 60 - 30 ) / 3412 which is 7Kw . So not mater if the element is 1Kw or 12Kw you will use 7Kw.

Another thing is to check your meter, turn everything off and make sure the light on the meter does not flash or readings change over a period of say 30 minutes to ensure you do not have any unknown loads connected.
 

Doug71

Established Member
Joined
28 Aug 2016
Messages
2,160
Reaction score
814
Location
Yorkshire
I just checked my usage out of curiosity. My heating and hot water are oil so the electric is just for electrical things.

I used 446 units last month so about 14.4 units a day.
 

Sideways

Established Member
Joined
26 Dec 2017
Messages
1,464
Reaction score
323
Location
United Kingdom
Family of four, small detached house. Gas heating and hob. Electric lights, oven and other usual white goods.
I looked fairly carefully at my last 12mth utilities when I was shopping for a new fixed term deal in September.
We use 10kWhr a day in summer and 18kWhr a day in December & January
I blame a lump of that on the tumble dryer.
HTH.
 

Phil Pascoe

Established Member
UKW Supporter
Joined
29 Jan 2012
Messages
22,001
Reaction score
2,077
Location
Shaft City, Mid Cornish Desert
Originally the usage was 45% day, 55% night - it was just viable to stick with economy 7. Octopus have confirmed that the No.1 reading is the night reading, so I'll read the meter at 7.30am to see what has been used over night. I'm still sure they are the wrong way around. The meter was changed a couple of years ago and the fitter left a card saying which was which but it's faded to the point I can't read it.
I fancy there is a bit of b.s. involved - they've informed me that my night rate is 23.00 - 00.00 and 01.00 - 7.00. I was told by the last supplier it was 00.30 - 07.30 and the one before it was 00.00 - 07.00. All GMT - the meter is not computerised and has not been touched so surely it changes over at the time it was originally set to change over?

My last month was 212 units by night and 527 units by day. I used Water Heating Calculator for Time, Energy, and Power to work out the consumption of the immersion - I can't see 212 units a month being adequate even if nothing else was used at night. The meter reads only whole units so unlike an old analogue meter it's not easy to see at a glance what's happening.
 

mikej460

Established Member
Joined
19 Jan 2019
Messages
954
Reaction score
592
Location
Daventry
Phil are you sure the immersion timer is set correctly i.e. 11pm not 11am? I've done this once :unsure:
 

Phil Pascoe

Established Member
UKW Supporter
Joined
29 Jan 2012
Messages
22,001
Reaction score
2,077
Location
Shaft City, Mid Cornish Desert
If I use too much hot water during the day it runs cold, and there is an indicator light on both the timer and the isolator switch (that was my first thought as well).
 

Just4Fun

Established Member
Joined
21 Sep 2017
Messages
897
Reaction score
268
Location
Finland
Turn everything off. All appliances, including the fridge & freezer - it won't matter for a short time. Then confirm that your meter is not registering any usage. If the meter still shows usage when you think you have everything turned off, you have something using power that you are not aware of so find out what.

Next turn things on one appliance at a time and try to judge which really starts your meter spinning.
 

MikeH

Established Member
Joined
25 Jan 2008
Messages
175
Reaction score
0
Location
Near Chester.
Shower? Do you use one rather than a bath and if so is it electric. They have a very high power draw.
 

Terrytpot

Established Member
Joined
9 Aug 2017
Messages
273
Reaction score
153
Location
Derbyshire
Having had to rely upon an immersion heater as our sole source of hot water in the recent past I feel it could be prudent to check that
1) the heater is functioning exactly when you expect it to..I had to replace one that started ignoring its set timings and operating when it felt like it..
2) more likely and also experienced historically is the immersion heater itself failing leading to it functioning for a much longer period of time to achieve what it would normally do much quicker. The thermostat on them is particularly vulnerable and if you live in a hard water area that doesn’t help either. Damhik but when you’ve had to replace them 4 times you start to dislike them, we eventually got ours plumbed in properly to heat water via our gas boiler.
 

Phil Pascoe

Established Member
UKW Supporter
Joined
29 Jan 2012
Messages
22,001
Reaction score
2,077
Location
Shaft City, Mid Cornish Desert
No, a bath from the immersion. The shower is mains power hot water from the immersion.

Ten units used overnight, so that's about par I would think. I'll see how the day goes.

The tank is three years old, a s.s. mains pressure one, the element (and thus the thermostat) is about four months old.
 

flying haggis

Established Member
Joined
7 Mar 2009
Messages
1,386
Reaction score
678
Location
norfolk
MILs meter has printed on it which is day and night displays so check that the meter might have the same. check the elec co haventswapped night/day readings. they seem to do it regularly! damhikt.
 

Woody2Shoes

Impressive Member
Joined
5 Jan 2015
Messages
2,077
Reaction score
357
Location
Sussex UK
"This is set to come on at night (the reason for e7) on an electronic timer"....
Do you really mean this?
The thing is, "off peak" electricity is a moveable feast. Your timer may be switching heavy loads on when the tariff is not in operation. In Scotland, certainly, and I know it's the other end of the country, e7 loads can be switched on (by radio signals, not an onsite timer) at variable times - depending on the mix of generation and demand.

I would try and study the timing of your (presumably radio controlled) e7 meter activity.
 

Phil Pascoe

Established Member
UKW Supporter
Joined
29 Jan 2012
Messages
22,001
Reaction score
2,077
Location
Shaft City, Mid Cornish Desert
It's set within the parameters of (all?) suppliers - 1.00am to 7.00am. I'm not aware of one charging full rate between these hours. It's not really the night time charges that concern me, it the daytime ones. I'll have look this evening for today's units.
 
Last edited:

xraymtb

Established Member
Joined
5 Nov 2007
Messages
537
Reaction score
37
Have you calculated what the bill would be on a single rate rather than E7? E7 being designed for storage heaters I'm not sure you would see any benefit without them. You can contact the supplier and ask to be billed on single rate instead and run the immersion when it suits you.
 

Latest posts

Top