Why is my electricity usage at night so high?

[Deleted User]

EachPenny wrote: »

Welcome to the forum.

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?

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.

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.

Excellent knowledge of timer switch springs EachPenny but I d be surprised if these springs can last 72 hours.. A power cut of that length I would guess is completely unknown , at least in my neck of the woods..Three days ! Never !.. even in the darkest Three day week Thatcher years when my Mining colleagues were chopping down local trees to keep warm, did we have a 72 hr power cut.
I would guess that of the many thousands of timer switch s I see and have seen and checked, that at least 50 % are grossly out, 25 % within the 2 hrs which suppliers are happy with and the rest not far off . There must be another reason.I suspect the spring weakens. I do have one in my garage . Its time I had a closer look at it.
Tampering with these is rare.They have metal seals.I ve never found one tampered, thats not to say they were nt tampered as they are off the radar for normal tamper checks with meter readers. I m probably one of the few in my area who paid them any attention at all.
People can lose out for years and years with these 24 hr analogue timer switches if they are not aware of just what time their cheap 7 hr s is on, others can gain too.

Slinky

slangrish wrote: »

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.

Are you sure that what you think is the rate for the night usage is the night usage and vice versa?


We've got a house with E7, have just got it back from the tenant. Have read the meters, and double checked with a kettle boiling, rate 1 which we thought would be day rate appears to be night rate, and rate 2 which we though would be night rate, appears to be the day rate. I couldn't work out when we first bought the house, did it up before renting out, why our night rate was using more units than our day rate as we don't have storage heaters or use appliances on the night rate. It could have been reported incorrectly for years as we stayed with the same company the previous owner used and they didn't query our opening readings.

Raxiel

Slangrish, I suspect, as others have said, the day and night figures are reversed. To repeat the question of others in this thread, do you have night storage heaters?


These are electric heaters that get hot (internally) overnight and then release that heat during the day, they are not the electric panel heaters that you turn on either with a timer or on demand when you want heat.


I ask this because Letting agents have a habit of referring to the latter as storage heaters, but they aren't. On-demand heaters are a lot more expensive to run, but are much cheaper for builders to install so they go in a lot of new build flats because these are typically rented and neither the builder nor the landlord care about the electricity bill as they aren't paying it.


These flats are also often fitted out with night storage for the hot water (pulsacoil or something similar) and an economy 7 meter unless the day and night registers get reversed. When I lived in a flat like that every single neighbour I spoke to had the same situation. And most didn't care since it worked out cheaper - as long as the supplier never realised the error.

EachPenny

Houbara wrote: »

Excellent knowledge of timer switch springs EachPenny but I d be surprised if these springs can last 72 hours..

Why? People have been making 7 or 8-day spring-powered clocks for centuries. The only difference with a time-switch one is the ability for the mechanism to self-wind using electrical power (somehow ).

Houbara wrote: »

A power cut of that length I would guess is completely unknown , at least in my neck of the woods..Three days ! Never !.. even in the darkest Three day week Thatcher years when my Mining colleagues were chopping down local trees to keep warm, did we have a 72 hr power cut.

It all depends where you are in the country. Towns and cities are less vulnerable to power cuts (more underground cabling and duplication of circuits). I lived in a rural area near the end of a single circuit 11kV supply route (not at all uncommon in rural areas). In the event of storm damage, the supply engineers would open all the circuit breakers along the 11kV line and then restore the supply one section at a time until they got to the end of the route. Any damage along 11kV spurs, or in the 240v feeds was initially dealt with by isolating them - in some cases simply by cropping the cables and connecting them to an earth spike. Restoration work then prioritised repairs that reconnected the most people as quickly as possible. Small hamlets and individual homes were far down the list, unless there were other reasons for urgency.

In the 1987 Great Storm we had no electricity for 5 days (the timeswitch clock stopped around 3 days in). In 1990 we were off for two-and-a-half days. And for four days in 2013. The E7 timeswitch was only checked and reset in 1987.

Houbara wrote: »

I would guess that of the many thousands of timer switch s I see and have seen and checked, that at least 50 % are grossly out, 25 % within the 2 hrs which suppliers are happy with and the rest not far off . There must be another reason.I suspect the spring weakens. I do have one in my garage . Its time I had a closer look at it.

I don't think that is likely to be a factor in short-duration power cuts - any decent mechanical clock will be designed to keep time over a wide range of spring tensions as the spring unwinds in normal use. I've heard that in some models if the spring completely unwinds it has to be rewound manually before the auto-wind system will function. But perhaps it is time you take a look at your one and let us know what you find. (Could you do a 'BigClive'-style teardown video for us perhaps )

Houbara wrote: »

Tampering with these is rare.They have metal seals.I ve never found one tampered, thats not to say they were nt tampered as they are off the radar for normal tamper checks with meter readers. I m probably one of the few in my area who paid them any attention at all.

I think that is an important point, along with the readers not checking to see if the timeclock is correct.

I'm not going to go into details, but I reckon it would be possible to change the time leaving nothing but a very small (<1mm) mark on an inconspicuous part of the case. If the meter readers themselves don't know how the timeswitches work then they probably won't spot signs of tampering... even if they were looking.