Night Storage & electricity usage

LD79

Hi everyone,

First time here, hope someone can give me some impartial advice and let me know what (if anything!) i'm doing wrong. Firstly a little background info:

I've recently moved into my own 1 bed flat in London which uses only electricity. I find myself with 1 storage heater in the living room and a hot water tank. After a week of poorly 'heated' water, I changed the heating element (3kw) in the tank, turned the thermostat down to about 55° and I haven't used the top tank at all. That first clicks on around midnight and then again a further 2/3 times in the night, until 7am. I use this water for the washing up and washing my face at nighttime.

The storage heater isn't turned fully up (it's on a dial and i'd say it's charging at about 75%) and has been on every night since i moved in. (It's also worth noting it is a single glazed property, although i aim to change this in the future!).

So firstly I don't particularly like the look of the old storage heater and am looking to change it. Seeing as its the only one that works, i'll have to change the one in the bedroom too. In order to make a more informed decision on whether I should replace them with new storage heaters, with water-filled heaters or convection heaters and along with recent price-hikes, I've been checking on my electricity usage.

What I have discovered has surprised me - but I am new to this so maybe it's the norm:

Over 2 weeks I have used 58kw of electricity during the night, and 221kw during the day. Over a 24hr period (sat-sun) I used 4kw during the night and 15kw during the day. I had the tv and lights on, have an electric shower, but didn't use the washing machine during this time... I would have assumed that those readings would be reversed (I checked the meter and I definitely have the right readings for the right times of day) as i thought that with eco 7 and storage heaters, most of the electric is used in the nighttime.

So - how come my hot water tank and storage heater are only using 4kw throughout the night? and is it usual to use this amount of electricity for a 1-bed (during the day)? I'm paying 16p per kwh in the day and 6p at night so at the moment this isn't working out to be very cost effective, and seems to justify my thoughts about switching from storage heating and getting 'normal' electric heaters...

macman

Other than the fact that heating and hot water on a single rate tariff will cost you around 260% more...
I'd say that your readings are definitely reversed; how can a 2 or 3kW storage heater charging for 7 hours only use 4kWh in one night, unless the input is set to a fraction of it's full capacity? How is the immersion heater timing controlled? You don't need it on for all 7 hours of cheap rate.
The tank 'stat should be set at 60C minimum to avoid the risk of legionella.

LD79

Thanks Macman - I checked the meter today before and after I run the washing machine and I definitely have the readings around the right way - this is why i'm so confused as to why its going up so little overnight and so much in the day. The hot water is on eco 7 so just clicks on and off throughout the night until 7am. I

Heating and hot water on a single tariff may technically cost me more, but if i'm spending 50% more on my day tariff where i'm using the most electricity then the savings might be comparable?

Richie-from-the-Boro

Storage radiator

- input set at whatever storage of cheap priced energy you feel you need to last 17 hours
- output closed completely, permanently, that way you get 80% radiated heat and only 20% convected
- storage is determined by three things (1) how many bricks (2) closed or open damper and (3) insulation
- the debate over the last several decades of price rises has changed, bedrooms are better with panel
- panel heating switched on an hour or so as required in the kitchen, bedroom, bathroom is now the thinking
- in your case the bedroom heater is easily relocated anywhere in the flat

The one in your living room will normally be a 3.4kW and the bedroom usually a 0.7kW. Like Cardew 7 hours at 4.1kW does not explain that usage. I'm assuming you have a~n~other form of supplementary heating switched on at core-rate during the day or the dampers permanently wide open. 16 & 6p rate is a good rate.

Immersion Heater

Assuming your water cylinder is a standard PartL compliant with the usual PartL insulation standards and a water controller there should be no need whatsoever to touch it. I've never used the top ]core-rate] element in 35 or more years, the stat means they are essentially plug ' play and best left alone. Two comments (1) its usually 'hard water' that boogars the efficiency of the heating element, and its (2) bad insulation that leeches the heat from the cylinder. All standard 11-27" UK elements are 3000W and have a thermal cut out to prevent boiling so just set and forget.

Timing of the 7 hour period are here

The usual but not always AMPY meter here

LD79

Thanks Richie
The water heater does basically take care of itself - since I changed the elements I have no need to put the top immersion element on, so I think its as efficient as it can be.

I have no other forms of heating and the storage heater vent is usually closed all day and night. I'm at a loss to explain why the day rate is so high, especially as I am at work for most of it! I'm beginning to wonder if its the shower using all the kw, or maybe the neighbours have connected to my meter..

Richie-from-the-Boro

LD79 wrote: »

Thanks Richie
The water heater does basically take care of itself - since I changed the elements I have no need to put the top immersion element on, so I think its as efficient as it can be.

I have no other forms of heating and the storage heater vent is usually closed all day and night. I'm at a loss to explain why the day rate is so high, especially as I am at work for most of it! I'm beginning to wonder if its the shower using all the kw, or maybe the neighbours have connected to my meter..

- no double glazing suggests no wall and other insulation especially in flats
- I had assumed lifestyle, as in home all day was a major contributor, but you work
- night store takes at least a week to get going in a well insulated dwelling
- for example add an open fire chimney, no glazing, poor insulation and sash windows and its a no-go

I'd spend [assumption is renting] on insulation before anything else. Panel[ing] the bedroom and other rooms and moving the small night store to your living area can be done later. GoTo a second hand shop or auction and buy some rich sod's megga heavy, lined, thick as carpet old curtains is a starting point - then run a test closed at work / open while at work / what's best ?

Thinsualte type shades / blinds are a better bet where you can't change the windows / frames. One heck of a price though and have to be bespoke .. .. as in the gaps are as important as the shade. A set of bespoke old fashioned wooden shutters with a thermal lining barrier [50%] will do almost as much as double glazing at 50%. NOTE - solid not plantation shutters which I gave only as a sizing reference.

The gaps are as important as the shades / blinds / shutters, if you are not able to build to a near zero gap, keep yer money in yer pocket. If you have a small window in the loo or wherever building a test shade / blind / shutter might be a worthwhile other avenue to explore. You can get them made, the Americans use them in their millions but buying efficient ready made with the right quality insulator is almost the same price a double glazing.

.......... something to ponder for those who can not for whatever reason have double glazing ...............

Heat Loss Reduction Values are ish !

- secondary glazing + insulated shutters 77%
- secondary glazing + heavy curtains 66%
- stand alone insulated shutters 60%
- double-glazing 55%
- honeycomb blinds 36%
- modern insulated roller blinds 22%

[Deleted User]

Hi,

just a silly thought, I know you say you are on E7, but is your storage heater wired into a spur socket, or is it on a plug,

DragonQ

What about the E7 timers? Some people have said before on this forum that the timers were totally out, so the cheap rate was some time during the day rather than at night.

lstar337

Sounds like a wiring/timer issue.

Do you have two fuse boxes?

Can you post us a picture?

Some installs are so poor, you need to make sure your NSH is only taking charge during off-peak.

LD79

Ok so I checked the meter/timer again this morning and despite me changing the clock on Saturday, it seems to be an hour out again. That may have been an operator error of course, but it could be a potential problem i'll have to keep an eye on...I have also read elsewhere that the old dial timers lose their ability to keep time accurately.

The water tank and storage heaters are wired straight into the wall and I have 2 fuse boxes, 1 for regular use and the other for the eco 7 (can take a photo later and upload this evening). It's my own place so I am looking to replace the windows with double glazing eventually... the heat side of things is OK (at the moment!), i'm just concerned at the amount of KW i'm using in the day and would like to get to the bottom of that before I replace all the broken heaters in the flat.

I took a meter reading before I went to work this morning so will check again when I get home and see how much i've 'used' whilst not being there!

lstar337

You should not be using more in the day than at night, that is just wrong.

If you have two fuse boxes then the night store box should only be live during the off-peak period.

What appliances do you use during the day?