Having moved into a flat, I have an immersion heater which is connected to Economy 7. I want to fit a timer so I can set it just to just come on during the night rate. I have no experience of knowledge of timers - obviously the feed wire needs to be able to be wired into the switch, the switch needs to be able to be screwed to the pattress, and the immersion heater feed needs to be wired to the other side of the timer.
Simple?
So what sort of timer should I buy?
We fit these at work, and they are very reliable:
This is probably as simple and cheap as the come, without being of dubious quality:
Surely if it's "connected to Economy 7" it'll already be controlled. Perhaps you mean that your flat has an Economy 7 supply but the immersion is connected to the general supply.
Max Demian <max snipped-for-privacy@bigfoot.com wrote in news: snipped-for-privacy@brightview.co.uk:
Surely unless a Storage heater circuit then it is merly a dial tarrif meter.
I had E7 in my last property. The whole house went onto it between midnight and 7AM, approximately. But the immersion heater was simply plugged into a 13A socket in the airing cupboard, so was only on E7 during the night. The rest of the day it was on at the standard rate, unless it was switched on/off manually, and someone remembered... I just used a plug-in timer, one of these
It is normal to connect the immersion to the general supply so you can "boost" the hot water during the day... If it wasn't on the general supply and you used all the stored hot water you'd have to wait for the off peak period to get more hot water...
OP is looking for an immersion heater controller this incorporates a time switch to switch it on during the offpeak period and a "boost" button that switches it on for say an hour when pushed.
I have E7. Everything is on it. The meter just records on the appropriate dials at the appropriate times.
Useful for several things, including self cleaning oven, running the washing machine, dishwasher overnight.
A pin timer or segment timer. Digital electronic timers are less easy to use & less reliable.
NT
Well when I had Economy 7 there was an immersion at the bottom of the tank on offpeak, and another one at the top of the tank I could have on any time I liked. The offpeak one was all I needed, but I did have an electric shower, so the tank was only needed for hand and face washing and washing up.
I used an earlier version of one of those when I had Economy 7. However one day I worked out that I did not use enough off peak electricity for the tariff to be worth while so I change to a normal tariff.
Pretty much
At risk of stating the obvious, its worth getting one designed for immersion control. That way with the better ones you get things like a "boost" capability where you can turn the immersion on manually for a fixed period of time at any time. So if you realised you need more hot water before the next nightly re-heat you can do it easily and not have to worry about manually turning it off again.
Mechanical ones are simple and easy to use but dumb (usually don't have battery backup to keep running in a power cut, or know what to swap to and from daylight saving time etc). They are typically 24 hour only. Many of them also make a certain amount of noise can sometimes be heard in a quiet room or get transmitted though the fabric of the building.
Digital ones give more toys and flexibility, and posher ones allow for different time settings on different days - which may or may not matter depending on circumstances.
In my case, the main E7/normal tariff control was a big mechanical clock adjacent to the CU. It was always set on GMT - never changed for BST, so in the summer E7 was on from 1AM to 8AM (or do I mean 11PM to
6AM - whatever). Anyway, it was important NOT to change the timer settings on things like dishwashers, washing machines, immersion heater etc.
It _is_ worth doing the calculation, because, in case the OP doesn't realise, the daytime rate is a little more expensive than the 'normal' tariff, and unless you use a lot of E7 electricity and not so much at the daytime rate, being on E7 can work out more expensive. Mine was borderline, so ICBA to change it.
Same here and the lack of battery backup with a mechnical timer means you have to remember to at least keep an eye on it to make sure culmlative power cuts haven't "adjusted" it's on time to oustide the cheap rate period.
A proper E7 immersion control is the best solution and I suspect you can get ones that deal with the two heaters situation as well. ie have a "boost" that only powers the top heater and thus only heat the top of the tank or "full boost" that powers the bottom heater and thus heats the whole tank.
I thought Economy 7 had two separate meters and all the economy 7 stuff was wired back to the E7 meter while the stuff you want on 24h/day went to the normal meter. In effect 2 different mains circuits with the E7 appliances only getting power from the meter when E7 rate kicks in sometime around 02:00? We have a hot-water tank with 2 immersion heaters, the upper one connected to the normal 24/7 mains and the bottom one coming on as above, same for the storage heater(s) presumably the "modern" approach is to switch the whole house to E7 rate rather than specific appliances?
Usually with that kind of setup, the E7 timer is what defines the cheap rate period since its control output is also fed to the meter, and controls which register the consumption is recorded against. They are supposed to keep on going during power cuts, but don't always.
(we had one that just decided to stop one day, and leave it permanently peak rate).
Yup, and if your wiring is split so that you have some parts only energised during the cheap rate period, then wire the immersion heater controller to the "always on" bit so that you have have boost during the day.
Thanks for the explanation Roger, I hadn't really thought about it before. Much appreciated. Cheers - Pete
When you say its economy 7, is it connected to the economy 7 supply, as this is in fact off during the day, so any timer used has to have a battery backed up clock if you want it to be on for different times during the off peak hours, ie just say for an hour, the than all the time economy 7 is live controlled by its thermostat only. However if you have it supplied from the normal supply, which mine is it can of course be controlled to come on any time, including during economy 7 times. I like this as it allows me to boost it should I need to at more expensive of course. Brian
I have a E7/daytime tariff meter.
I did a excel exercise to work out the breakeven point between e7 tariff/daytime tariff vs Standard tariff given the pence per kWh for each tariff.
I plotted a graph where the x -axis showed the % to E7 to total electricity running from 0% to 100% and a straight line plot of the standard 24 hour tariff.
The graph showed that if 33% or more of your total electricity was during E7 hours it was cheaper than 24/7 standard tariff.
I have kept an eye on my two sets of meter readings and for the past 9 years, 33% of my electricity consumption has been during E7 hours so my bills literally sit on the breakeven point so both tariffs worked out the same in the final billing!
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