Official MSE Economy 7 Guide discussion

QrizB

dingue said:

Modern panel convectors using electronic thermostats properly installed are a fit and forget option - silent 100% efficient, nil maintenance cost. 

... but, as @Gerry1 would say, eye-wateringly huge running costs. Panel convector heaters are one of the most expensive ways to heat a house, even more so if you're running them on daytime-rate E7.

Let's look at your example.

dingue said:

I use an immersen heater to supply hot water and wall mounted panel convectors in each room, 9 in total. Average annual consumption 12,000kWh.

Let's say your immersion heater uses 10kWh/day, every day. That's 3650kWh on night rate electricity. Your other 8350kWh will be on day rate.

And let's use EDF's standard variable rate card for the East Midlands (it's the top of the card).

• E7 is 13.4p/kWh on the night rate and 35.28p/kWh on the day rate. Your 12000kWh will cost you £3434.98.
• If you were instead on single-rate electricity at 27.63p/kWh, you would be paying £3315.60, a saving of almost £120/yr.
• If you had storage heaters and moved 4000kWh of your E7 day rate (heat) to E7 night rate, you'd be paying £2559.78, a saving of £875/yr.

And that's sticking with electricity. Gas would be cheaper again.

Gerry1

dingue said:

I use an immersen heater to supply hot water and wall mounted panel convectors in each room, 9 in total. Average annual consumption 12,000kWh. Room temperature 19-21c throughout the whole house 24/7 (3 bed semi). If you believe that gas would be cheaper because of lower energy cost per kW then you need to provide time and temperature figures for a similar house.

You're using panel heaters on E7 peak rate? 

Even at the new capped single rate, 12,000kWh of electricity at around 28p/kWh would cost around £3,360 plus the daily charge.  Gas at around 7.3p/kWh would cost around £973 plus the daily charge assuming the boiler is 90% efficient.

Do you work for Fischer Future Heat by any chance?

dingue

Hi Gerry1. My current energy supplier, British Gas, tariff Energy Plus Protection fixed till March 2024 v8. Night 14.311p Day.19.16p. Standing charge £129.37 (year). 60:40 day/night split gives an average 17.7p kwh. Rolling 12 month current annual bill £2050. The April and October price cap will not change my prices, they are fixed till 2024. No I don't have any connection with Fischer Future Heating. Their heaters are a strange hybrid between storage and panel. Very dodgy sales practices and been in trouble with Trading Standards for making false claims backed by high pressure sales techniques. Avoid at all costs. 

TheAble

QrizB said:

Let's look at your example.

dingue said:

I use an immersen heater to supply hot water and wall mounted panel convectors in each room, 9 in total. Average annual consumption 12,000kWh.

Let's say your immersion heater uses 10kWh/day, every day. That's 3650kWh on night rate electricity. Your other 8350kWh will be on day rate.

Why would you use any day rate electricity to heat the water? Surely you'd heat the tank just overnight? At least that's what I used to do.

dingue

Indeed I do heat the water at night using a time switch. Take a look at my YouTube video (wattsupmike?) it's an old video and the prices are completely out of date but the performance figures remain true. 90% efficiency for combi boilers may be true but how efficient is the whole system? Quote me a figure and a published reference to support that figure. Good luck with your search because I have yet to find one. My theory is that the efficiency of most gas systems is very low but we never get to know that because there are too many variables. 

QrizB

TheAble said:

QrizB said:

Let's look at your example.

dingue said:

I use an immersen heater to supply hot water and wall mounted panel convectors in each room, 9 in total. Average annual consumption 12,000kWh.

Let's say your immersion heater uses 10kWh/day, every day. That's 3650kWh on night rate electricity. Your other 8350kWh will be on day rate.

Why would you use any day rate electricity to heat the water? Surely you'd heat the tank just overnight? At least that's what I used to do.

Maybe read that again?

QrizB

dingue said:

Indeed I do heat the water at night using a time switch. Take a look at my YouTube video (wattsupmike?) it's an old video and the prices are completely out of date but the performance figures remain true. 90% efficiency for combi boilers may be true but how efficient is the whole system? Quote me a figure and a published reference to support that figure. Good luck with your search because I have yet to find one. My theory is that the efficiency of most gas systems is very low but we never get to know that because there are too many variables. 

The fact is that the average gas CH user manages to heat their house and water on 12000kWh/yr of gas, paying around a quarter as much to do so as you pay using electricity.

Good luck with your energy bills.

TheAble

QrizB said:

TheAble said:

QrizB said:

Let's look at your example.

dingue said:

I use an immersen heater to supply hot water and wall mounted panel convectors in each room, 9 in total. Average annual consumption 12,000kWh.

Let's say your immersion heater uses 10kWh/day, every day. That's 3650kWh on night rate electricity. Your other 8350kWh will be on day rate.

Why would you use any day rate electricity to heat the water? Surely you'd heat the tank just overnight? At least that's what I used to do.

Maybe read that again?

Ok fair one  Misinterpreted your post.

JBMouse

Not sure if this is the correct forum for this post, so here goes:
I was on economy 7 over 10 years ago, but decided back then that I was not benefitting, I currently only use 18% of electric at night, so my then supplier  EDF changed my tariff to a single rate, but leaving the E7 meter in place, using it as a 'pseudo single rate' meter, and I had no problems. I moved supplier to Avro energy in 2019 and they also operated the meter in exactly the same way, pseudo single rate. As they ceased trading I was moved to SOLR, Octopus, and I have had constant problems with them trying to sort out my meter. I received no electricity bill for 6 months, despite emailing them, including photos of the meter, now I have just received a back dated bill but with an economy 7 tariff being applied. To make matters worse they have given me a new MPAN number showing a different code for the time switch portion of the number, I have phoned them and, long story short, they say they cannot do anything and ECOES can't or won't allow it. Am I being given the run around? I do NOT want a smart meter which is their solution  but I don't think this is correct. Can anyone shed any light on this.  Before I retired some many years ago i worked for EDF in Data Collection investigations, so I have some detailed knowledge of the systems in use, but may be out of date now.

dingue

I sympathise with your problem. I too have had incorrect billing. Suppliers just can't cope with dual rate meters confusing day and night use. I have also noticed that the difference between day and night rate has become less and less over the years together with a higher standing charge. This leads me to think that they are trying to squeeze E7 out by stealthily making it not worth the hassle. I've used E7 for over 40 years and use about 40% at night and save about 10% compared with standard single tariff. A smart meter was installed 5 years ago but refused to allow its smart function to operate - it's a dumb smart meter! That way I'm in control of the readings and so far no problems with billing.