Immersion Heater

[Ilovelindor]

Exciting topic I know!

Our house is electric only. Not connected to gas mains. We do not have central heating, each room has electric wall heaters. Our hot water is immersion heater/boiler only. The shower runs off the hot water.

What do people find is best with their immersion? On all the time? On a couple of hours a day? I'm experimenting with how often to have ours on, but don't seem to be using much less electricity and I am just ending up with cold water. It was on 2 hours this morning and all the hot water seems to have been used on two sinks and DH's shower!

I heat mine over night when my electric is cheaper. This last 3 days for me and Dd.

We have Economy 7 so ours is on overnight when electricity is cheaper.

My immersion is heated by the gas central heating and I put it on for 45 mins/hour in the morning. This gives us 2 showers and a bowl of washing up water. I then put it on again for 45mins/hour in the evening if needed for others to shower....there are 3 adults, 1 teenager and 2 younger kids in the house. If noone wants to shower/bath in the evening, I don't put it on.
When I moved into the property last year, it took us a while to figure out the heating/water set up and the previous owners had set it to just be on heating water constantly....cost me £80 in electric for 1 month!
Immersion tanks should have thermostats so in theory will cut the heater element off if the water is up to temp, but personally I think it's cheaper to heat what you need rather than constantly (as if the water temp cools slightly it will click on to heat and then can take time for that heat to reach the thermostat), but am interested to see if someone can properly clarify this!

the cheapest way is to heat it just before you need it. So if you shower in the morning put it on an hour before the shower and turn it off before you get in the shower.

If you leave them on all the time it just eats electricity.
make sure the tank is really well insulated as well

We only put our immersion tank on if we are having a bath which could be weekly in the winter. I have only had it on a few times during the summer. We have electric showers though.

Ours stays off unless we'd like a bath, in which case we turn it on an hour or so before to heat up and then it goes back off again. We've been doing it that way for years. We do have electric showers and a dishwasher however. So cold water on tap isn't needed.

During the summer ours is on for the last hour of the economy 7 period. Longer if somebody wants a bath.

but am interested to see if someone can properly clarify this!

As far as I am aware, the tank thermostat (if fitted) controls the gas boiler only. The electric immersion heater has its own separate built-in thermostat.

I’m in a similar situation and moved into this place at the very end of April this yr.

When I first moved in it was on all the time and my electric bill was c.£100pcm. The water was always boiling and plentiful.

After the predicted rises I started to only put it on as needed from roughly start of July onwards, short amount (30-45mins) most days and longer for a bath (sometimes forgetting to turn it off for an additional hour or so, but it’s on roughly 10-15% compared to 24/7).

The water is fine but feels frugal as sometimes it’s a bit tepid or if you really fancy a shower or bath then there can be a wait for water etc and trying to remember to turn it on/off and the result of this on my bill was that it’s been…….

Exactly the same!!! C.£100pcm

So I’m not convinced it makes much difference!

Nb. My shower isn’t electric - it runs off immersion as well.

I have an oil tank but it was empty when I moved in and I haven’t yet filled it or used it yet. So am currently 100% electric and immersion for hot water. (Also have dishwasher so it’s just for bathing etc).

ThistleSifter are you sure that is your actual usage or just what your direct debit is per month?

It’s usage as the amounts have been generated following meter readings I’ve provided; I don’t have direct debit and just transfer the money, so am accurately charged per every kWh I’ve used plus standing charge. @SarahMused

I also bought a portable 100w solar panel and battery which I’ve exclusively been charging my phones and power packs from since c.July, so I expected those things (immersion + solar) combined to be more effective.

I did that free gousto box on here then £100 credit in referral so an endless stream of meals arriving until last week … so been cooking more recently lol - I love cooking but often have a salad or something easy/quick if it’s just me. Although the oven is LPG so not sure how much electric it uses (if any?!??) so that may explain it either way.

For context i wfh full time but live by myself atm, I don’t have electric heating, only oil (empty tank atm) and a log burner. It’s a 3 bed house. I have a tv but just occasionally watch Netflix/YouTube. Use hairdryer daily. Shower daily. 1-2 deep hot long (& topped up) baths a week/when I fancy it. 1 Mac and 2 digital radios are on 24/7. Lots of lamps with proper Edison bulbs. But I wouldn’t say I was a heavy user at all but may be wrong!

Don’t really use a kettle but do use a big coffee machine which runs c.3 x day 😅
No tumble dryer but probably average a washing machine load/day
Dishwasher which runs at least once/day.
Two Hepa air purifiers running 24/7

Thats pretty much everything electric I use aside from water and doesn’t fluctuate.

My mum always keeps hers on as it’s the actual heating of the water that takes the energy, so heating from a higher point/maintaining the heat seems to be equally as effective as the water running cold and then the boiler working much harder.

So having tried both ways the cost is the same as my hot water usage didn’t change as I didn’t start having shorter showers or anything, but one way makes it harder to live, the other way feels like hot water panacea.

There's probably an optimum middle ground but either extreme (always on vs hardly on) seems to be roughly the same.

I am on E7 and have put a timer on the immersion heater circuit.

It heats up for 20 mins at 5am and is enough for my daily shower, and a small amount of washing up. I've checked on the smart meter display and I use roughly 1 kWh of electric overnight each night, this includes immersion, fridge freezer, broadband router, etc.

I am really frugal with electric during summer months as during winter I have ancient storage heaters that can cost £5 upwards each day <faints>

I am on E7 and have put a timer on the immersion heater circuit.

Ours is linked to the Hive heating controller that schedules off and on times. It also means that I can boost it from my phone if necessary.