Son buying all-electric flat. What should he do with immersion heater?

System

This discussion was created from comments split from: All electric flat w/ Electric heaters (Not night storage). Best option for hot water?.

19DENBO48

Hi, My son is buying a 15 years old single bedroom flat that is all electric, at present it has an immersion water heater supplying kitchen sink-bathroom sink and a thermostatic over bath shower, would he be better removing the unvented immersion and having an instant hot water heater or boiler fitted, only one at a time of the outlets will be drawing water at any one time...Thank you. 

Rodders53

Unvented (i,e mains perssure) Hot Water system is miles better than any instant hot water system as none of the latter will supply enough water to give a satisfying shower in winter.

Keep it!

QrizB

19DENBO48 said:

Hi, My son is buying a 15 years old single bedroom flat that is all electric, at present it has an immersion water heater supplying kitchen sink-bathroom sink and a thermostatic over bath shower, would he be better removing the unvented immersion and having an instant hot water heater or boiler fitted, only one at a time of the outlets will be drawing water at any one time...Thank you. 

How is the flat heated?

If it's with storage heaters (and hopefully it is) he'll have an Economy 7 electricity supply and having a storage tank with an immersion heater is likely to be cheaper to run than an instantaneous heater.

If it isn't storage heaters, what is it? He might want to look for a different flat, or to budget for replacement heating ...

tacpot12

Only if his water use is very small should he consider an instananeous water heater, e.g. he washes all his dishes using a dishwasher and takes short showers. Only then would it be worth changing what he has. 

The unvented cylinder is likely to be well insulated, so will not lose too much heat. 

A time-of-use tarriff might allow him to heat a full tank of hot water and do his washing and tumble drying when electricity is cheap, leaving just cooking as being the main use of expensive day-time electricity. 

An air fryer might save him a lot of electricity compared to a full-size oven if he is cooking for one.

19DENBO48

QrizB said:

19DENBO48 said:

Hi, My son is buying a 15 years old single bedroom flat that is all electric, at present it has an immersion water heater supplying kitchen sink-bathroom sink and a thermostatic over bath shower, would he be better removing the unvented immersion and having an instant hot water heater or boiler fitted, only one at a time of the outlets will be drawing water at any one time...Thank you. 

How is the flat heated?

If it's with storage heaters (and hopefully it is) he'll have an Economy 7 electricity supply and having a storage tank with an immersion heater is likely to be cheaper to run than an instantaneous heater.

If it isn't storage heaters, what is it? He might want to look for a different flat, or to budget for replacement heating ...

That flat still has the original Dimplex panel heaters fitted when the modern 3 storey block was built in 2009

QrizB

19DENBO48 said:

QrizB said:

19DENBO48 said:

Hi, My son is buying a 15 years old single bedroom flat that is all electric, at present it has an immersion water heater supplying kitchen sink-bathroom sink and a thermostatic over bath shower, would he be better removing the unvented immersion and having an instant hot water heater or boiler fitted, only one at a time of the outlets will be drawing water at any one time...Thank you. 

How is the flat heated?

If it's with storage heaters (and hopefully it is) he'll have an Economy 7 electricity supply and having a storage tank with an immersion heater is likely to be cheaper to run than an instantaneous heater.

If it isn't storage heaters, what is it? He might want to look for a different flat, or to budget for replacement heating ...

That flat still has the original Dimplex panel heaters fitted when the modern 3 storey block was built in 2009

Panel heaters are what @Gerry1 calls "cripplingly expensive" as a heating system.

Is there any chance he can buy a different flat instead? If not, he might need to budget £5k to have them replaced with storage heaters, or alternatively pay perhaps £500-1000 a year more in electricity than he otherwise would. Or just be cold in the winter!

See eg. this thread for someone in a similar position:

https://forums.moneysavingexpert.com/discussion/6581967/where-can-i-get-advice-on-my-heating-options

Scot_39

I saw many one bed flats with e7 for HW and live panel heaters - last year when looking late 23 with niece - but thier EPC estimated heating needs were fairly low.

People tend to under focus on the costs of hot water - it is non trivial if have a low heating demand.

My immersion heater - takes upto c3kW even on low use days - my shower sadly not from the tank - another 1.5-2kWh. So 4-5kWh per day including one shower - so 1500-1800kWh pa - that's larger than (my lower than average admittedly) heating cost for a 2 bed home. The Ofgem median TDCV for all electric is now only 3900kWh pa.

Bring any amount of off peak storage tpye heating into the equation - and multirate electric would swing the balance to cheaper than conventional SR.

Edit : even running the heaters for 1-2 hrs at the end of e7 night window would last a good few hours - and again shift load to night rate.

Although it is possible that some of the pseudo e10 type deals at likes of challanger tomato - lifestyle ??? - could work well too - with 2 or three low ratd periods suitable timings.But maybe not if relying on alcs meter switching.  Most of tge cheaper installs I saw were 4 port meters and timers on immersion.

But for e7 to pay - in a modern 1 bed flat - would probably easily get away with one large NSH - one medium lot 20 / HHR storage panel in hallway would push it even further (doors onto kitchen, bedroom and bathroom).

Maybe even just one large initially - but for comfort I'd do 2 - and heat the LR warmer than rest of flat.

The most referred to in many posts here - Elnur / Dimplex largest model HHRs with flexible programming etc retail about £900-1000 on line - but you would have to get a quote for installation and wiring mods.

Living room and if can afford it to get it done and out the way - before decorate etc - maybe a second mid size in hall - with passive air circ heating from it doing the bathroom, bedroom, kitchen.

If two full blown HHR models a stretch - digital controlled lot 20 - like Dimplex slimline or Creda TSRE cna be £200-£300 cheaper for the largest size models.  

I would certainly consider those lower priced units for my hallways - as only need something to provide a consistent low base temperature 24.7.

And then get onto a decent e7 tariff - or the more recent snug octopus with its cheaper night rate (with 1 hr in winter afternoon boost) to drive them and the hot water tank.  Unlike SR - there can be a few pensce difference between off peak rates in same region across suppliers (Ofgem set a total price cap - suppliers set a see-saw tpye balance around it between offpeak and peak unit rates - so lower off peak - comes with higher peak - but if use enough on lower off peak - you still win)

The pay back will come not only on bills but potentially future resale - a single modern storage heater is reportedly from some posts here often enough to lift EPC ratings sligthly etc over the panel based alternative. 

As buying its unlikely to be a short term commitment - will get some pay back - even if some of the payback has to wait until "trades up" the property ladder in later life.