Immersion Heater - actively heating all day?

DomM21

Hi there,

My friend and I have just moved into an all electric flat and it is currently a big unknown of how much the energy bill will be. We are using heating sparingly, have an electric shower and have an immersion heater. I have read many horror stories recently around immersion heaters and how much they cost to run. When we moved in a few weeks ago the immersion heater was on and we have left it this way. It only makes the kettling sound once we use hot water (only for washing up and washing hands) which makes me think it’s only actively using power at these times which makes sense as it will be heating the new replacement cold water. Is this true? Or is it actively heating all day and silent? Better prepare myself for a horrific energy bill if so!

Thanks

Gerry1

Welcome to the forum.  Unfortunately the news is not good: electricity is a very expensive way to heat a property.

However, the room heating and the electric shower will be the main offenders, less so the immersion heater.

What is the room heating. e.g. Night Storage Heaters (big and heavy and on the floor) or panel heaters (thinner and probably fixed to the wall)?

What is your electricity tariff, e.g. Economy 7 (Day & Night meter readings) or Single rate?

Did you read the meters yourself (NEVER rely on anyone doing it for you), register with the existing supplier and set up a Direct Debit?

EssexHebridean

It’ll be ticking over against the thermostat the rest of the time I suspect.

what was your opening meter reading on moving in, and what is the meter reading now? The units used will give you an idea of your costs (remember to add on the standing charge) so you can’t least be fully informed.

do you have electric heating as well, or is that using gas? 

Does the immersion heater have one switch to power it on/off, or two? 

matelodave

The thermostat will keep topping the tank up to maintain the set temperature - for most people a hour or two a day is more than sufficient, especially if you've got an electric shower which is heating water whilst you are showering.

Are you on an Economy 7 or single rate tariff - if on E7 you could save money by just having the hot water tank on for an hour or so around 6am and having shot showers (3-4 minutes max) before 7 am and after 12am (midnight) *

What sort of heating have you got, if storage heaters, then its likely that you are on E7, if they are just panel heaters then you may not have E7.

Take a piccy or two of your heaters (or tells us the make and model) and post it on here and you might get a few tips. As you are aware leccy heating is the most expensive way to heat your place barring burning £20 notes, but there are ways to mitigate the cost a bit by using it carefully and understanding what is using it and when. If you monitor it by reading the meters regularly and check that your bills are correctly based on actual meter readings and not estimates, you get a better understanding on how to control your costs.

*I've edited it to delete my mistake - apologies to all

k_man

As above, the immersion heater will use a small amount of energy keeping the tank hot. But as long as it is well insulated, this won't be much (1 - 2 kWh a day).
If the tank is central to the flat, this also isn't completely wasted as it adds to the heating of the flat (less useful overnight or in the summer).

So while there are some savings by reducing the time it is on (which makes sense if there is a timer fitted already) the potential savings are probably bigger elsewhere, especially heating

DomM21

Hi all,

Thank you very much for these helpful replies. Positive news is that in the last hour I have discovered that the immersion heater is a dual model with an off peak and on peak switch. The off peak is the switch which has been on so hopefully it has only been using the cheaper electricity at night. We do have an economy 7 tariff etc.

Heating wise it is storage heaters in the living room and hallways with electric radiators in our rooms. We have only used the electric radiators (for about an hour to an hour and a half) each day in the last week due to the cold and have left the storage heaters off.

macman

You'd do much better to use the NSH's and switch off the convectors, when possible. The convectors will cost about 250% more per kWh.
So, for the cost of running the convector for 90 mins, you could charge the NSH of an equivalent rating for nearly 4 hours.
The good news is that you are on the cheapest form of electric heating with the immersion and NSH's.

Gerry1

matelodave said:

on E7 you could save money by just having the hot water tank on for an hour or so around 6am and having shot showers (3-4 minutes max) before 7 am and after 12pm.

A shower after lunch will be at the expensive peak rate. 

The OP needs to find out the exact switching times of their E7 meter.  Don't rely on what the times ought to be, look at the meter on the wall and see when it actually changes over.  Note that in some areas there may be a two-hour gap in the middle, which can be handy for 'double dipping' last thing at night and first thing in the morning.

It's worth taking monthly readings (you should be doing this anyway) doing the sums and seeing whether a more suitable tariff is available by switching suppliers.  Single rate prices are virtually the same from nearly all suppliers (bar a few green ones) but E7 varies quite dramatically between suppliers and between regions.

matelodave

Sorry I meant 12am - apologies

EssexHebridean

Heating with night storage heaters - once you learn how to use them to best effect - doesn’t need to be as ruinously expensive as people often suggest. This is particularly true if you make the best use possible of the off peak overnight rate and load-shift everything you possibly can to it.

Do you know what the make and model of the NSH’s you have might be? 

I’m in a two bed flat - we have 4 NSH’s installed, use two (the other two are in the bedrooms, that we don’t need to heat) and currently my dual fuel DD is set at £115 per month - plus of course the EBSS £67 a month payment too. We joined our current supplier in October so started with a zero balance then - and we’re currently well in credit although a good chunk of it will be swallowed with this month’s bill I imagine. We use electricity for everything apart from cooking, which is gas. Our shower - like yours - is electric, and hot water is via an immersion which generally we just leave switched on often the off-peak circuit. We usually heat to around 18.5 - 19°C, so plenty comfortable enough. 

Scot_39

Immersion heaters are thermostatically regulated.

If you have a modern designed dual element system and E7 - then generally should only need the E7 - which I believe tends to be near the bottom of the tank - but willing to be proven wrong.

The second heater - is generally more of a boost - unless run a lot of water like a bath - shouldn't really be needed most days if ever if only talking few dishes and rinsing face / hands etc.

My single element immersion (c3.2kW roughly) activates 3 times a day - as on E10 rather than E7 - but typically - unless used a lot of water - for less than an hour in total even in winter. So maybe 2-3kW daily. 

In winter that helps heat the house a little (in summer when I can be bothered I sometimes stop it heating 1 or 2 of the three times a day - as loses a lot less heat mass - warmer water in, lower losses out etc).

People say immersion wastes a lot - on basis they don't ever use the full tankful - so there's posters here saying left their's off - and just use kettles for dishes / shaving etc etc. But then that to me seems like an inconvenience to save part of the c60-70p a day at my off peak rates.

Compared to that 2-3kW - my heating uses upto 25kWh on colder days - so savings and changes there - add up far quicker over winter.