Why is my electricity usage at night so high?

Thomas1000

I live in a small two bedroom bungalow,and from 1986 until 2016 it was heated by night storage heaters,untill spring 2016,when an air source heat pump system was installed.

I did not realise just how much more I was paying for energy.The whole place is electric only,and if there was a cold winter I was using 65 kWh on the coldest days - the heaters were on Eco 7.In a year I would use 11500 kWh,which is an average per day of 31.5 kWh.

The new system uses just an average of 15.2 kWh per day through the year.I don't trust the Eco 7 system,and suspect it may get confused with power cuts.( An engineer from one of the companies told me this himself).

The distribution costs for off peak energy seem to be increasing,and I'm glad I changed to a single rate tariff.What will happen when all those electric cars start to be charged at night?

sevenhills

slangrish wrote: »

I have Economy 7 meter and am currently on Solarplicity's Standard Variable Tariff
September 2018.

Would a fixed tariff be cheaper, do you also need to be on an economy 7 tariff to match your meter?

EachPenny

Welcome to the forum.

Thomas1000 wrote: »

I live in a small two bedroom bungalow,and from 1986 until 2016 it was heated by night storage heaters,untill spring 2016,when an air source heat pump system was installed.

I did not realise just how much more I was paying for energy.The whole place is electric only,and if there was a cold winter I was using 65 kWh on the coldest days - the heaters were on Eco 7.In a year I would use 11500 kWh,which is an average per day of 31.5 kWh.

The new system uses just an average of 15.2 kWh per day through the year.

What was the capital cost of the new air source heat pump system, and how many years life do you expect to get out of it? That (worked out on a cost/day), plus the ongoing maintenance costs needs to be added to the daily consumption cost in order to work out your true saving (if any).

E.g. In rough terms if your unit cost was 10p per kWh, you are saving £1.60/day or £584/year. That means you will only break even (ignoring the costs of maintenance) if you paid less than £5840 for the system and it lasts for 10 years. If you paid more than £5840 for the system (and include the cost of maintenance) then you will need it to last more than 10 years, just to break even. Do you expect to still be living in the same house in 10 years time?

Thomas1000 wrote: »

I don't trust the Eco 7 system,and suspect it may get confused with power cuts.( An engineer from one of the companies told me this himself).

If this 'engineer' carried out any work on your supply then you might want to contact the company and ask for someone to come out and check the system, as his apparent lack of knowledge of how the things work would make me have doubts about the quality of his workmanship.

Old E7 meters are either switched by a radio signal or a timeswitch. The timeswitches have a 'spring reserve' which keeps them running accurately for (typically) 72 hours or so. Therefore only a power cut exceeding 72 hours (typically) would result in the timeswitch becoming 'confused'. A cut of that duration would be an infrequent and major event. Meters switched by radio signal will simply revert to the correct operation by themselves. Modern meters use digital clocks with battery backup (or remote switching) and would continue operating accurately for weeks with a power cut.

Old mechanical timeswitches could be out of sync with E7 times for other reasons (long-term drift, not set correctly to start with, tampering etc) but they will still operate consistently, they won't be 'confused'.

All the householder needs to do is to check when their E7 hours are and make sure all their appliances are timed to operate in the correct time period. Given that standard E7 hours are set at a time of typical minimum demand, it follows that an out of sync meter creates the potential for any error to be to the benefit of householders.

Thomas1000 wrote: »

The distribution costs for off peak energy seem to be increasing,and I'm glad I changed to a single rate tariff.What will happen when all those electric cars start to be charged at night?

By then nearly everyone will have a 'Smart' meter, and Time of use tariffs (TOU) will be the norm. Your switch to a single-rate tariff will have been in vain.

macman

EachPenny wrote: »

But the OP is using roughly 66% at night (somehow) and is benefitting from having E7 as a result.

The actual consumption is more important than what appliances are installed and being used.

They are using 66% based on one winter bill. What needs to be calculated is the night rate percentage based on a full year's usage, which will be far lower.

slangrish

thanks, i'm not sure i'd know how to locate the thermostat so might need to ask a plumber friend to investigate further.

to my knowledge Solarplicity only now has two tariffs - fixed and standard variable, both of which have the same rates.

EachPenny

macman wrote: »

They are using 66% based on one winter bill. What needs to be calculated is the night rate percentage based on a full year's usage, which will be far lower.

But the OP says they don't have the heating on. In which case, other than extra lighting, their winter consumption shouldn't be much higher than average.

macman

But to make any sense of this we need to see the annual figures.
OP, the immersion heater stat is fixed to the tank, usually where the cable entry from the switch is. Maybe under the cover plate. It's an electrical job, no real plumbing skill needed.

macman

You can't use this board to offer or solicit referrals. Use the referrals board, as you have done for all your other offers.

coffeehound

Surely there must be a meter fault here? A 3 kW immersion heater could only use 72 kWh per day at worst, so does not account for the usage*. OP have you checked the meter serial number against the one on the bill?

* well it could, but is unlikely

From previous threads on here, it could be: wrong meter, faulty meter, paying for (a lot of) communal lighting, multiple properties wired into the same meter..

.

slangrish

will check on the meter as other than hot water for showers and coffee machine in the morning, there's nothing massive happening. like i say, we don't use heating in our flat and have a pretty standard flat with white goods, etc. i'm baffled why the night usage is what it is when we're only here and using stuff after work until 10-11pm.