All electric flat w/ Electric heaters (Not night storage). Best option for hot water?

APCElectrichomeowner

Hi @QrizB
 - Just to be clear, you're suggesting that it's actually more economical to be on eco 7? 

Additional thought for context:
- This was quite a mild period, meaning I haven't really had to use the heaters. I need to review this again after this month to understand the actual impact if colder weather

Can I also ask how you're coming to those figures? Likely a simple calculation, but EDF doesn't actually tell you what they are, or if the day rate is inclusive of the night rate. I've called to clarify it isn't, but am still having trouble understanding the kw calculation now I've read the figures you've suggested. 

Thanks so much for your help! 

Gerry1

The sums are quite simple.  Find out the price per kWh for each rate.  (Note that the figures on the bill need 5% VAT added whereas it will be included on a quotation.)

Multiply the difference in meter readings for each rate by the p/kWh price and add the daily or standing charge (same VAT caveat).

Then do the same thing for single rate, noting that the standing charge may be different.

Then compare the prices from.other suppliers.  Single rate will be much the same on the SVT but the E7 price split varies significantly.

Most suppliers (not Ovo) will happily bill an E7 at single rate.  It might even be worth being on E7 in the winter and single rate in the summer, although that's more likely with NSHs.

EssexHebridean

Take the reading from the meter on the 15th, and subtract the reading from the meter from the 1st from that. Do that for each register, and it will tell you how many units of each rate you have used in that fortnight. 

If you've not used the heating that much, then when you do you can expect the day use to increase significantly.

APCElectrichomeowner

Thanks @Gerry1, I understand that. My question was even simpler though, it's what units the readings are. Are they in Kwatts? Ie. Here's how I would have logically approached the readings. 

Night Rate + day rate = 100% of usage for that day
Night rate converted to a % to understand how much electricity as a proportion is used at night vs day. 

I'm not looking at comparing different providers right now, but I will. This exercise is to understand if E7 is the right type of tarrif for me based on my usage, or if I'd be better off on a normal SVR. 

@EssexHebridean - this makes me think I've been wrong in how I looked at it. Are these readings accumulative then? When do they reset? 

The EDF support on the phone indicated these were daily readings, but I'm now more confused than I was earlier!  

Gerry1

@APCElectrichomeowner Electricity meter readings are in kWh.  Think of them like the odometer on a car.  If a rental car had 10,000 miles on the clock, they charged 10p/mile and you returned it showing 10,500 miles then the mileage charge would be £50.  There'd probably be a daily rate as well, similar to the electricity standing charge.

kW readings are comparable to speedometer readings.  If the speedo says 70mph and you drive at that speed for an hour, you've burned up 70 miles; if you have a 3kW heater (immersion or panel) and it's on for 2 hours without the thermostat kicking in, you've used 6kWh.

Just to confuse the issue, some smart meters and portable displays (IHDs) also show kW.  This can be useful to show whether you're 'speeding' but electricity meter readings should always be kWh.  Conversely, gas meter readings should be sent as m³ or (hundreds of) ft³ because the gas calorific value (how 'concentrated' it is) varies.

APCElectrichomeowner

@Gerry1 - thank you for being so helpful. The comparison is useful.

I am starting to question my own sanity here. Maybe the best way to get this through my surprisingly thick skull is to go back to the readings from 15th December

15 Dec 2023

Day reading

1,810 

Night reading

568

Are you saying that I'm using 568 KW/h at night, and 1,810 kwh during the day? That these aren't total values? 

Gerry1

It means that since it was installed the meter has recorded 1,810kWh used in the daytime and 568kWh used at night.

You wouldn't be charged any more if you drove 500 miles on an old rental car that had 70,000 miles on the clock when you picked it up and 70,500 when you returned it.  It's only the increase in the kWh or mileage that counts !

APCElectrichomeowner

Wow, really? That seems like such an illogical way to measure it! Was this system designed by cave dwelling racoons? 

Thanks anyway. You've been far more helpful than the EDF website, or their support team, who when challenged were '100% sure' that the ratings were daily usage figures, using the quoted numbers above. 

TheElectricCow

APCElectrichomeowner said:

Thanks @Gerry1, I understand that. My question was even simpler though, it's what units the readings are. Are they in Kwatts? Ie. Here's how I would have logically approached the readings. 

Night Rate + day rate = 100% of usage for that day
Night rate converted to a % to understand how much electricity as a proportion is used at night vs day. 

I'm not looking at comparing different providers right now, but I will. This exercise is to understand if E7 is the right type of tarrif for me based on my usage, or if I'd be better off on a normal SVR. 

@EssexHebridean - this makes me think I've been wrong in how I looked at it. Are these readings accumulative then? When do they reset? 

The EDF support on the phone indicated these were daily readings, but I'm now more confused than I was earlier!  

For electricity things are nice and easy, 1 unit is 1 Kilowatt-Hour (kWh) and this will be the unit of measurement the meter displays its readings in. So if the meter says 1810 that can be referred to as 1810 units or 1810kWh. 

Gas readings can be slightly more complex as an additional calculation is involved and older meters record in imperial units rather than metric units, but luckily we don’t need to get into that here.

The reading on the meter will be the total of all electric use since it was installed, this won’t reset but it is worth remembering they can go “around the clock” so after a reading of 99,999 the meter would go back to 00000.

To see the energy consumption for a specific period you need to know the difference between two readings on separate dates, by simply subtracting the old reading from the new one. 

So if you wanted the usage for 24 hours you would have to read the meter once and then read it again the same time the next day, the change in the numbers is the total units used in that time. With a Day and a Night reading you would have to do this for each reading, and your logic for determining the proportion of night usage is otherwise fine.

Smart meters can also collect daily (up to half hourly) usage data automatically, which some energy suppliers will show you in your online account - this could have been what EDF support were attempting to say. There are a few other services around that will allow you to see this information, such as the Bright or Hugo mobile apps which get mentioned here often.

APCElectrichomeowner

@TheElectricCow

Thank you! Hugely helpful as well. I've just downloaded Hugo. I'm going to monitor this over the next few weeks and see if I can get a clearer steer on my usage. 

Longer term, I am still very much considering the benefits of either an electric shower, or a electric combi boiler for water purposes only. 

The information you've given me will help me greatly in understanding what the best approach is. Thanks again for taking the time.