Immersion, electric meter, and Electrisaver

ianpwilliams

Hi all, I’ve just moved into a new flat, and I have a few questions if anyone can help (I have asked my letting agent as well but thought it would be useful to get some knowledge of experiences here too if possible).

The hot water tank is an immersion heater, but it has two switches (top and bottom). I believe that this is meant for top switch for hot water for washing hands, washing up etc., and bottom switch is for baths etc., is that correct? If so I only have a shower, so will I need to use the bottom switch at all?

Also I am aware that there is a never-ending debate about whether immersion should be on for an hour or two a day, or 24 hours, and the general consensus seems to be that having it on 24 hours is s little more expensive, but not hugely so. I believe that my electricity meter (I have no gas supply) has a day and night rate (the night rate is 12:30am to 6:30am), however as there is no timer on the immersion I don’t think I’ll be available to take advantage of the night rate. Maybe I could just leave the top immersion switch on overnight each night, and off during the daytime?

Also my electricity meter apparently has two supplies, one for the storage heaters (which I am also trying to get to grips with), and one for the electric sockets. However I can only see one meter reading, even when switching through all of the displays. Also, that single reading hasn’t gone up since I moved in on Friday, which can’t be right. Has anyone else had any of these issues? There is also a boost button on the meter, does anyone know what that might do?

Finally, there is an Electrisaver panel in the kitchen, which the immersion top switch suggests is connected to it. Reading online suggests that you can use the Electrisaver to turn off whatever is connected to it after 30/60/90 minutes in case you forget, is that correct? Also there is a boost button, but I don’t know what that does. Has anyone else had experience with one of these?

I’m aware that it will be more expensive to heat my home using only electricity, so I would be very grateful for any advice or info that you can send my way.

AndyPK

its all very much dependent on how its wired.

first you need to find out whether you are on economy 7.

talk to your electricity supplier to find out what tarriff you are on, and as you say, look for 2 readings.

You really need to be on economy 7 with storage heaters.

If you are, you basically have the bottom immersion on over night, and then if you are short of hot water in the evening, press boost 15 or 30 for a top up (uses the top element)

ianpwilliams

Thanks, you were right, turns out I’m on Economy 7, and the top immersion switch runs through the Electrisaver so I can leave the top switch on all the time, and I’ll need to do the bottom switch overnight. I’ve also got storage heaters, and YouTube has informed me that I need to switch the storage heater on overnight and then use it the following evening.

Thanks for your help.

CashStrapped

OK the flat you have moved into has an E7 set-up.

This means that during the day, your electricity is pretty expensive, however at a set time during the night (usually around midnight till 7am), it switches to a night rate which far cheaper...usually around 30 - 50% less.

Over the course of your annual use, the majority of your electricity bill is made up of space and hot water heating. This can make up 60% of your annual bill.

So, your flat set-up is designed to use most of heavy use items (space heating and hot water) on the cheaper rate. It can be very cost effective if used correctly.

You should therefore use as little of the heavy use items on the day rate. No immersion boost, and no portable heaters!

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Storage Heaters

In your case, you have storage heaters and a hot water cylinder. The circuit for these should only come on after a certain time. No need for you to go round turning them on and off.

The storage heaters heat up very dense bricks inside them during the night. During the day, they slowly give off this heat, keeping the flat warm, without using the day rate electricity. How much they charge and how quick they release the heat depends on the settings.

As a rule, the Input dial should be set based on the weather for the next day. Very cold day? Set the input high. Mild day? set it low.

The Output dial should be left to the lowest setting. It should be turned up sparingly and only if you want more heat released for a short period. It should always be set back to the lowest setting, especially at night. The lowest setting should ensure enough background heat for the whole day. If you turn it up, it could release too much heat and you won't have enough stored for the evening. If you leave it turned up during the night, it will fail to store much heat as it will just release it immediately.

You do not need to turn them on and off every day/night. The circuit should activate by itself. You should only turn them off at the socket when you do not want them to charge i.e during warmer weather.

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Hot Water

The tank in an E7 property has two heating elements:

The top one only heats the top of the tank and is considered a boost. This will use expensive day rate electricity. It should not be used (or only used if really needed).

The bottom element heats the whole tank during E7 hours. The tank should be well insulated. The logic is that the whole tank is heated on the cheap rate and this should be enough to last the next day.

Some people find that they do not need a whole tank of water for just themselves. They avoid heating the tank at all and just use an electric shower and a kettle for the hot water they need. While these two items use the expensive day rate, because they are only using/heating exactly what they need, it works out cheaper than heating a whole tank or a quarter of a tank.


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Tariff

Next you have to look at your tariff. An E7 tariff has two parts. A day rate (expensive) and a night rate (cheap). As you use the flat, you should find (especially in winter months) that you use more electricity (proportionally) on the night rate. This indicates you are using the set-up correctly.

For example:

After a years worth of use, the total annual amount of electricity used was 6000kwh.

Out of this 6000kwh, 3600kwh was on the night rate and 2400kwh was on the day rate.

In this example, this would mean that 60% of my total use was on the night rate.

This is called your night use % and is important for comparison purposes.

You do not need to wait for your annual use to work it out. You can start checking what it is based on daily readings (taken at the same time each day).

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The problem with E7 all electric set-up's is that people do not bother asking how they work and how to get the best out of them. They use them inefficiently and then say they are expensive and rubbish. This is not the case.

So, if anything is unclear, do not hesitate to ask further questions.

Hopefully that rough guide helps

ianpwilliams

Thanks very much.

So I can leave the storage heater on 24hrs a day, because it will only take on heat during the nighttime rate? That!!!8217;s good to know, and I guess I can make sure that it does do that by checking the two meter readings during peak time.

And I should also leave the lower immersion switch on 24hrs a day for the same reason? And I!!!8217;ll never use the top immersion switch, or the Electrisaver as that appears to only relate to the top switch.

I!!!8217;ll take daily meter readings too to make sure I!!!8217;m using it correctly.

CashStrapped

Yes, the E7 circuit (storage heater and bottom immersion) should not activate till after a certain time, when the cheap rate starts.

You should be able to confirm this yourself very easily. With a cold water tank, during the day, turn the bottom immersion on. It should not be receiving any power to heat the tank. Simple!

Your storage heaters may have a fused spur socket with a red neon light on. They are not active unless this light is lit. The sockets may not have a light, it is just helpful if they do.

Yes, take daily meter readings at the same time each day. Do this for a week or so to get an idea of your daily use. From this you can see your overall daily use, and work out your % split as I said.

You can also ring your current supplier and ask them to supply an indication of what the property has used in the past. This will give you a good indication for comparison on a comparison site. You should check to see if your tariff is competitive.

I try to take a meter reading once a month. This also ensures your direct debit is set at an appropriate level.

ProDave

Yes leave the lower immersion switch on and it will only heat up at the off peak times.

What people fail to explain is you have two consumer units. One for all normal things like lights and sockets, that is powered all the time. You also have a smaller one for the storage heaters and bottom immersion heater. That consumer unit only gets turned on (by the suppliers metering equipment) during the off peak periods.

The electricsave only needs to be used if you have used a lot of hot water and used up all that was in the tank from last night. If you do run out of hot water, use that and it will heat just the top half of the tank, but it will be charged at the peak rate.

ianpwilliams

The storage heater is working now which is great. However, if I wanted to heat the living room over night if domeone stayed overnight in there, would it be possible to do that given that the storage heater heats up overnight and then releases the heat the next day? In those circumstances would I turn up the input so that more heat came in, and have the output slightly higher than minimum so that it released a bit of the heat, but hopefully not all of it so there would still be enough for the next day?

AndyPK

yeah you would open the output a little at night


although if they are old and leak energy you may not need to bother

ianpwilliams

Brilliant, thanks for the help everyone, much appreciated!

CashStrapped

I would just re-iterate that the output should always be on the lowest setting for the majority of the time.

Normally even modern storage heaters will leak enough heat as they charge, even on the lowest output setting. This is usually enough background heat to keep a room warm during the night.

The output should always be on the lowest setting at night. Otherwise it will leak too much heat, and there may not be enough stored by the bricks for the next day.

Turning up the output should be done sparingly, for short bursts and always returned back to the minimal setting.