But it’s not a house, it’s a one bed flat.

A 1 bed flat has the published average use of 2800kwh/year explicitly excluding heating and hot water.

Thanks once more to everyone for your help – really great. All has been passed on and I am waiting to see what she actually decides to do, and what the outcome is.

There seem to be breakers for two lots of under floor heating, one on each board. The programmer can only be connected to one of them, so it’s possible that the other (bathroom?) is on 24/7. There’s also a breaker for a towel rail – if that is on, it could easily use 5 – 10 kWH / day.

There also seem to be two breakers marked boiler- What does each of them feed?

Where is she?

Get someone round to identify properly the circuits, and sort out what heating and hot water she actually has.

What’s the rating on the towel rail and is it on all day?

Looking at the photos, i think the setup is an electric boiler and unvented cylinder.

Knowing how bad these things are set up and how most electricians are less than competent at heating wiring I would be looking at  those. Check the thermostat on the hot water cylinder as if it is too high then the water will never reach temp and the boiler will be on continuous, could be a 6kw electric boiler, on for 2 hours as you say, there’s 12kw right there if it is never satisfied, could even be a 9kw version……

Thanks again. What temp should the boiler be at?  She swears that the towel rail and heating  are switched off, but the meter doesn’t lie and SOMETHING is on! As MrsJ told her – there isn’t a ghost using your electricity.

60c

The thermostat is on the hot water cylinder and should be 55 deg. C, the boiler will need to be higher than that minimum 65 otherwise again it won’t satisfy the hot water and will be running continuously.

The thermostat on the cylinder may be behind a cover and have a scale of numbers like 1-5 instead of temperature which is a pain!

My last place was a 2 bed new build flat, electric only. We used approx 3500 kWh per year, no boiler – electric panel radiators that we rarely turned on, and an unvented water cylinder.

The unvented cylinder was set to heat overnight for a few hours. If needed, that is you’d used up all the hot water, the ‘immersion’ switch on the wall by the cylinder could be flicked on, but we were warned by the builder not to leave it on as you’ll eat through electricity.

Might not be relevant, but assuming some form of electric heating isn’t on, I’d be double checking the immersion switch for the cylinder is off.

Sometimes, unhelpfully, the 2 switches on the wall are not labelled, but both shouldn’t be on. At least that was the case in my flat.

So, to update this saga. Daughter had an electrician in and he basically confirmed what you suggested- as soon as the hot water heater is turned on the usage shoots through the roof. His diagnosis was that it’s because the boiler is old and obsolete and the only solution is to replace it. Not a surprise but not what we wanted to hear.

Next question- what should she replace it with? What types of boiler exist and what should she go for if the priorities are low electricity usage and reliability?

Electric boilers are like kettles – a heating element surrounded by the water. Unless the element is covered in limescale they’re all about the same. The only thing that makes a big difference is the insulation of the tank. Also worth making sure that none of the hot taps drip.

Reduce the timer on the hot water – maybe heat once a day – certainly reduced our gas use since winter by reducing the timer for water, when we don’t have heating on.

Were’ a heavy electricity user, but average 15-17 KWh a day (watched monthly and recorded on a spreadsheet) – 4 adults and at least one person at home every day.

His diagnosis was that it’s because the boiler is old and obsolete and the only solution is to replace it.

I’d be getting a second opinion on that, you only need to replace an obsolete boiler if there’s broken parts you really can’t replace and being old isn’t a valid reason either. Can these things be flushed/cleaned if the reason for inefficiency is loads of limescale?

A massive heater coming on will always make the instantaneous consumption shoot up, you’re probably increasing the demand by 10x in seconds. The amount of usage is due to how long that load stays on for, inefficiency is the problem, not age.

His diagnosis was that it’s because the boiler is old and obsolete and the only solution is to replace it.

Rubbish – Murray has it.

I’d be getting a second opinion on that, you only need to replace an obsolete boiler if there’s broken parts you really can’t replace and being old isn’t a valid reason either.

Very much this!

Can you clarify what the boiler heats the water for…. is it to heat water for radiators as well as water for baths, showers, etc.or is it just for the latter?

(I know there’s UFH in at least one room but that’s electric)

What does she use the hot water for?

You could avoid the need for a boiler full of hot water if she has an electric shower and an instantaneous water heater for washing her hands.

A dishwasher is a very efficient option as it only heats the water you need for the wash. You can get small counter top ones for £200 – £300.

There are much more efficient electric heaters available but they are not cheap. We put one in a shared family holiday home, I was surprised at how much heat it puts out from a rating of 1500w. Way more than the 3000w it replaced. No idea how it does though?

Just checked mine and we use an average of 12.73 kWh per day and I work from home and drink lots of tea. The power shower I know uses a lot.
My neighbours just bought a new car so I’m hoping his electricity bill is not zero.

Two thoughts:

1) An electrician is not (usually) a Gas Safe engineer. I’d perhaps file this under “false authority.”

2) When was it last serviced?

1) An electrician is not (usually) a Gas Safe engineer. I’d perhaps file this under “false authority.”

It’s an electric boiler, not a gas one.

Leaving an immersion heater on all day is as good as burning her £10 notes instead. Yes they have thermostats – but even a well insulated tank still loses some heat (which results in the thermostat turning the element back on to get back to full temperature).  It’s why an airing cupboard finishes off drying clothes- the lost heat from the tank heats the air.

And if the tank insulation isn’t great, or even worse an old style with a strapped-on jacket rather than molded onto the cylinder… £££ down the pan.

In terms of £££, most UK houses use gas for the true high-consumption uses (heating, hot water for bathing and in the tap, and many the cooker + hobs too).  Being electrical instead trebles their operating costs as E is about 3x the price per kwh than gas.

Our overall bills went up markedly a few years back when we changed the gas cooker and hob to electric (lots of reasons to like the induction hob though).

I’d perhaps file this under “false authority.”

Or not reading the thread correctly 🙂

Maybe, but she using 17kwh per DAY.

Even if she was in the shower for an hour on max heat that would probably only be about about half of that.

Yup, and having had a teenage son who could easily stand day dreaming in the shower for an hour plus it’s not beyond the realms of possibility.

Reduce the timer on the hot water – maybe heat once a day – certainly reduced our gas use since winter by reducing the timer for water, when we don’t have heating on.

Yes, unless you’re ploughing through the hot water use, the unvented hot water cylinder should only need heating for a period to bring back up to temp. Different circumstances probably but I’ll mention it anyway in case it’s of some use – I accessed the dial on the cylinder to turn the temp down (as hot water out of the taps was far too hot), and set it to turn on between midnight and 4am where it could use the Economy7 cheaper rate to heat up. We never ran out of hot water (2 adults, 150l cylinder).

Assume there isn’t something like an ‘eco’ mode available on the  boiler? I use this on our combi boiler so that the boiler doesn’t keep firing up several times all day just to keep a bit of water hot and ready.

Next question- what should she replace it with?

What controls are on the water heater? is the temp set too high, or timer set wrong for usage?

Might be worth knocking it down to 60c if it’s set higher…i.e theres no point having scalding hot water comming out of the hot taps/shower if your’e just going to mix it back down with cold water at the tap/shower head to make it comfortable!

as soon as the hot water heater is turned on the usage shoots through the roof. His diagnosis was that it’s because the boiler is old and obsolete and the only solution is to replace it

So there’s a boiler, as well as an unvented hot water cylinder?

I don’t know enough about it, but is the control of the unvented cylinder done from the boiler? (My system had a Dimplex control panel where you’d set the on/off state for the cylinder, and electric panel heaters if you wanted).

On second opinions, unvented cylinders need particular qualifications and these are stated on people’s Gas safe register profiles.

I get the point that water getting hot requires a fixed amount of energy and there’s no way round the laws of physics :-). What I’m wondering is if a new “kettle style” boiler might have less energy loss for some reason (which I can’t imagine is actually very big) and secondly if a “heat on demand” boiler might be less wasteful as she’d only be heating the water she needs?

currently she only uses it for washing herself (at home that involves soaking in the bath for hours but now I imagine it’s showering) and some minimal amount of washing up (she had a dishwasher).

EDIT – for new readers – we’re talking about a fully electric system

So, to update this saga. Daughter had an electrician in and he basically confirmed what you suggested- as soon as the hot water heater is turned on the usage shoots through the roof. His diagnosis was that it’s because the boiler is old and obsolete and the only solution is to replace it. Not a surprise but not what we wanted to hear.

Taking a step back here.
An all electric property is always going to have higher energy bills than a similar property with gas heating – electricity is about three times more expensive per KWh than gas. Hence this is something to factor in when weighing up places to rent/buy along with the other ownership/rental costs.

The boiler is a large high power device, you can think of it a bit like a supersized kettle, the power draw will be high while it is on. The relevant question here is how long is it on for per day, and why?

Next question- what should she replace it with? What types of boiler exist and what should she go for if the priorities are low electricity usage and reliability?

Generally it is wise to treat self-serving advice with some skepticism – the electrician would benefit from being paid for installing a new boiler.

A new gas boiler might be 10-15% more efficient than an older one due to the introduction of energy-saving features (condensing, etc) that reduce how much heat is lost in the exhaust gases. However, this is not the case for an electric boiler, as these just dump heat directly into the water, so you’re unlikely to get significant energy efficiencies from a new electric boiler.
Tweaking habits is more likely to sace money than a new boiler e.g.:
– For central heating (e.g. in winter) use the clock to turn on the heating only when the place is occupied rather than heating when nobody is home.
– Heat water on-demand rather than storing hot water which will leak out heat over time (an exception to this would be if there is an variable tariff).
– Change showering habits – less time, lower water flow, shorter, etc.
– Limit use of hot water for washing up e.g. use a bowl rather than free flowing water. Nowadays I mostly use cold water and only use hot for stubborn stuff.

I very much doubt an old immersion heater can be significantly worse than a new one. They are just turning power into heat, there’s nowhere for it to be lost.

Inadequate insulation on the tank is another matter (though if in the interior of the house, that heat is offsetting other electric heating anyway, assuming heat is wanted, which it probably isn’t in the summer).

If she’s using a lot of hot water (long showers!) then maybe the usage isn’t so unreasonable.

Is washing done by electric shower or from immersion heater?

Electric shower and instant hot water would cut back on unnecessary heating of water.

What tariff is she on, switching could also save £

Don’t know if they can be set up for electrical heating rather than gas (but I assume so) – one of the bast things we got when we needed a new boiler, was getting a ‘Hive’ device / app for controlling the heating.  It allows much finer control of timings etc than an older style on/-off or rotating segment timer, and thermostatic temp settings too.   It also means we can turn the heating on or off as necessary remotely, eg if we are later home than planned, use the app to delay the heating, or turn off completely if away (yes thst can be done without a Hive device/app, but not when you’ve already left home !).

To rewind a bit – one of the photos she sent has 3 isolators labelled Immersion, Boiler and Underfloor Heating. I’ve now confused myself to where I’m not sure what is the difference between “boiler” and “immersion heater”?

Boiler could be CH and HW with the immersion as a backup for HW.

It’s an electric boiler, not a gas one.

Ah, mia culpa. As you were.

Who’s Mia?

On top of all this, I’d start researching time of day electric tariffs like Octopus Agile. 1st thing is to find out if it’s possible to fit a smart meter, 2nd thing is to research whether there’s any controls for water heating that work smartly with Agile or just set the timer to heat in the expected cheapest period which I assume will mostly be 12am to 4am (tonight’s Agile prices for me probably averages something like 2ppkwh between 12-4am)

ASHP instead of the electricity boiler?

More efficient. More expensive though.

Might be worth knocking it down to 60c

Yes. For various reasons.
We run our system boiler at 60C. 55C in summer.

Who’s Mia

dunno but I knew her Manma

Can she take pictures of radiators, boiler, HW tank to help us out a bit here?

Next question is, how long are her showers?

ASHP instead of the electricity boiler?

Not possible….. it’s an apartment in a purpose built block

I’ve now confused myself to where I’m not sure what is the difference between “boiler” and “immersion heater”?

And this is why we need to know just what the setup is.  Is the room heating wet (i.e. radiators or wet UFH) or just electric panel heaters?

Assuming it’s radiators heated by the electric boiler – does the boiler also heat the water in the unvented tank?
(heating water in a boiler with electricity to then heat water in the tank would seem slightly inefficient when you could cut out the middle man)

A decent unvented tank doesn’t lose a huge amount of heat – my 210L Megaflo loses 8c over 24hrs if left alone – to reheat that would use 2kWh…… not very much really.

Incorrect you could fit a heat recovery ASHP, and I know of an internal version that you run ductwork to outside for the air intake etc. Still not cheap.

you need to check the temperatures of the stored water.