Working out consumption

Miami

Hello,

I've been making notes of my energy readings in order to work out my consumption, so that I can see where I'm over-using electricity. (It's not that I can't afford the bill, but I'd rather see my money go into my savings account instead of EDF's pockets where possible )

I'm on an Economy 7 tariff, and I work late shifts (usually) so I consume more of my energy on the night rate with the exception of things plugged in 24/7 and showers if I'm taking them before work while I'm still on the day rate. I'm on a long weekend from work at present, so I figured it was a good time to work out what I'm using from my meter reads.

21/01 -- day 25911, night 16430
24/01 -- day 25915, night 16473*
25/01 -- day 25916, night 16476
26/01 -- day 25919, night 16484

*For those three nights, I had my night storage heater switched on. Sometime between the 24th and the 25th, I turned it off -- forgot to note down exactly when.

25/01 is low, because I didn't use any heating at all that night. 26/01 is when I had a portable heater plugged in for about 3/4 hours. To avoid any skewed results, I showered at a family member's flat and didn't use the washing machine, so my usage across those days was similar, with the exception of the heating.

Because I can't find the readings I took on the 22nd or 23rd, I'll just divide the first reading by three. 43kWh used over 3 nights / 3 = 14.3kWh. Apparently I use 3kWh on a typical night with no heating. So, I'll subtract that, which gives me 11.3kWh a night for my night storage heating. It runs during my Economy 7 hours, so if we divide that by 7, it shows that roughly, my night storage heating uses 1.6kWh.

Working out portable heating is the same -- 10kWh - 3kWh used by other appliances = 7kWh. However, because I had it on for less time*, I divide by 4 hours instead = 1.75kWh.

So, the portable uses more than the night storage heating, and subsequently costs more. However, the NSH must be kept on for the 7 hours all night, so if I only want heating for a couple of hours when the weather's milder, the portable works out cheaper.

Have I done all that maths right? I'm hoping to work out how much my washing machine and shower cost me tomorrow by reading the meter before and after using them and not using any other appliances except the 24/7 things like boiler, fridge, freezer, broadband router etc, and I just want to make sure I'm not wasting my time working it out completely the wrong way. Thank you in advance

(*The reason I didn't keep the portable heating on for seven hours was because it isn't safe to leave unsupervised and I wanted to go to bed. I could have switched it on earlier, but I was feeling warm and if I'd gotten hotter I'd have needed to open a window which imho defeats the purpose of heating )

CashStrapped

Are you just asking if you have calculated your usage correctly?

It looks like your calculations are pretty good. Usually, you can get the model of the storage heater and the side of it and find online the manual and what rating it has.

The good news, looking at the readings you have given over the 5/6 day period is that you are using the Economy 7 system very well.

The average over the 5 days (taking the initial reading on the 21st) is 1.6KWH per day (Day Rate) and 10.8KWH per day (night rate).

This means you are using 87% of your electricity on the cheaper night rate. This is very good. Are you using the washing machine/tumble dryer on night rate? Or is this just heating.

The "bad news", even though it is winter, 12.4KWH could be quite high use if you just live on your own and it is a one bedroom flat. However a lot of factors are involved in this so it may not be too high. It all depends on the property type and usage habits, size/number of heaters.

Do you live alone? Is this a one bedroom flat? How many night storage heaters do you have in the flat and how many do you use? Do you understand and use the storage heater controls properly? Or do you just set them on their highest settings?

Have you only just started taking actual readings? Or do you have confirmed readings over a longer period. It would be useful if you have readings that span a period of a year to get an idea of long term usage. Look back in your bill history to find them.

Miami

Yes, that's what I wanted to know

I'd been away prior to the 21st at my mum's, so had done washing while I was there. I live alone in a one-bed flat, just moved in in December so I don't have any prior history (was previously living with mum). I don't have a tumble dryer, and I haven't used my washing machine on the night rate yet -- used it on day about 3/4 times on a quick wash before I went away, not used it since my return because I prefer to do a full load but will be using it tomorrow morning at 6am* and intend to do washes at 6am in the future.

There's only one storage heater in my flat (there's an electric one in the bathroom that's ancient which I never use) and no instruction manual. There are two dials on the storage heater, both with * 1 2 3 4 5 to select from, one dial says Input and the other says Output. Googling the model and make told me that the Input is the amount of heat the heater generates overnight and 1 = little heat, 5 = a lot of heat. The site recommended setting 4, but I found it too hot in the mornings when I'm sleeping underneath a duvet so I set it to 3. Output is the boost of extra heat and the lower the number is, the earlier the boost occurs. I set it to 2 in the hope I could get an afternoon boost but I can't really feel the effect, so if I decide to switch the night storage heater back on, I won't bother with the boost. It doesn't help that the night storage heater is located right next to a single glazed window that's five times the size of the heater

If there are any heating engineers / electricians / people who have the same heater who can offer better advice, I'd love to hear it! The make is Vent-Axia and the model is VASH18A.

That five day period includes three night on a night storage heater, one night with no heating, and one night with a portable heater, so I'm not sure how accurate it is with regard to average daily consumption.

I don't use hot water daily -- probably every two or three days -- is it worth turning off the boiler on the days I don't use hot water? Or would the cost/energy used by the boiler firing up again negate any savings made by turning it off? Would the night storage heater need the boiler to be switched on? :think:

CashStrapped

Ensure your water tank is well insulated.

It should have two heating elements. One near the bottom, this is the larger one that will heat the whole tank on Economy 7 rate. The small element is near the top heats a bit of the tank as an emergency boost during the day (on the expensive day rate).

Depending on how well insulated your tank is, it is always advisable to use the E7 rate to heat the tank and avoid use of the boost element.

You night heating sounds about correct. I would find out what is using 3KW per night.

That is 0.45KW per hour. I normally 0.17KW per hour at night in background appliances.

Finally what tariff are you on? If at the moment you are using 80+% of your electricity at night then you could save a lot by being on the best tariff avaliable. The best E7 tariff can vary based on how much you use at night.

Unfortunatly you do not have annual figues to go by so you will have to make some conservative guesses.

If you take a more conservative estimate and put that figure at 50-60% and estimate your yearly usage at 4500KW per year (that should be doable if you are using around 13kwh per day in winter). See what the best tariff is for your area compared to what you are on now.

www.energyhelpline.com is a good place to start.

Edit: Play with the yearly figure. You could assume that for half the year you may use half the amount of electric so that would give you a prediction of 3559KW per year. You may use a lot less than that, so it is up to you what you think you will use.

Miami

Yep, the water tank heats on Economy 7 and the immersion (boost) is always turned off. The boiler has something I can only describe as very hard yellow foam wrapped around it, I presume that's insulation?

At night, the following are switched on / plugged in, excluding any kind of heating:

Fridge
Chest freezer
Cooker (only when in use)
Broadband router
Phone/tablet charger
Laptop (although I plug the phone into the laptop's USB port if both are on at the same time instead of using two sockets)
Boiler
4x LED lights in kitchen (at least they look like LEDs to me)
Kettle (but plug switched off when not using)

I don't think I've missed out anything else... :think:

I've looked at a few comparison sites but most of the results average at 7 or 8p per night rate kWh of electricity. EDF are charging me 6.30p per night rate kWh.

Could a faulty extractor fan be the cause? Mine was whirring but not extracting, although I didn't realise until last week when I was speaking to neighbours who had the same problem. The fan was only replaced this morning (well... technically yesterday morning ) so perhaps the old one was using more energy than it should have been?

CashStrapped

Chest Freezers! I remember reading somewhere they can use a lot of electricity. Find the model number and the manual or work it out yourself.

Can't tell if this is the case iwith you....but...worth a check.

Also, unless you use internet at night, unplug the wireless router each night before you go to bed. In fact only plug it in when at home. It should not lose it's settings.

Boiler? I asume you mean water tank?

Regarding Energy tariff:

For my area (using 4500KW per year) First Utility comes out as best for E7 at 55% night use with unit rates of 7.242 night, 10.849 day and a 14.76p per day standing charge, paying by Direct Debit. £453 predicted cost.

At 70% night use Eon is chepest with a night rate 5.061p, Day rate 13.514 and a 16.42p per day standing charge.£397 predicted cost.

So it shows how much the best tariff can change based on your night usage %.

Miami

Oooh, I'll take a look at my instruction manual when I can get access to it (currently decluttering and everything's in front of the drawer it's in) but mine is brand new and energy rated A, so it shouldn't use as much as other freezers. I'm also sure they consume less electricity when they're full, and mine is about 75% full right now, which should help? :think: Digging out the manual shall be on today's list...

I do use internet at night, it's when I'm awake That said, my flat has awful signal so I rely on wifi to send/receive messages during the day while I'm running around etc. It's currently plugged in underneath my bed, but I'll see if the phone line's long enough to move it to a different plug socket.

Whoops! Yes, I do mean the water tank -- I grew up for over twenty years with gas central heating and combi boilers. Water tank has only been in my vocabulary for less than two months so I keep saying boiler instead

CashStrapped

A rated is good. Maybe my info was about old ones. Still check what it is rated to use in KW though.

The router, although in the scheme of things is not a big user, can add up to around £35 a year. For such a small device, it is quite a lot.

You seem to be on the right track though. Just try and get your background use as low as possible. Good tariff and use night tariff a lot more than day!

matelodave

It's not usually a good idea to keep unplugging your router - they work in conjunction with the equipment at the exchange to optimise the line settings to give you your best speed which can take several days.

If you keep switching it off then some routers will go through the whole sequence all over again.

Most routers nowadays go into a low power consumption mode when they aren't in use so it's best to leave it switched on but make sure that your computer is shut down overnight

CashStrapped

Interesting matelodave,

I had never thought of that and it makes sense ( I have a virgin media line).

However, I had read recently that BT had switched off DLM (which could affect the connection speed in this way if the router was turned off.).

DLM was causing alot of problems, so as far as I know is still not operational.

http://www.thinkbroadband.com/news/6726-assia-court-case-forces-openreach-to-turn-off-dlm.html

So you would not have a speed problem/reduction turning the router off.

Eitherway, if the op wants to reduce electricity use, she can try it, and if it adversly affects speed then stop it.