If an oil boiler is replaced with electric, does the central heating system also need to be replaced

GustyGardenGalaxy

I realise that the running cost of an electric boiler is currently about 2 to 3 times the cost of oil, but that aside I'm curious about installation. Will an electric boiler 'plug into' an existing heating system (both hot water and central heating with water filled radiators) or does the whole heating system need to be replaced?

matelodave

It's more like 4-5 times the cost - it's something you'll probably regret.

However to answer you question if the radiators asized correctly, the plumbing is in good nick and the boiler has sufficient capacity to provide sufficient heat then it will probably be OK but as in all thing you need proper advice rather than the collective wisdom of a forum.

But the collective wisdom will be to avoid an electric boiler - they are probably the most expensive way you can find to heat a place.
Even Fischer and Rointe heaters would probably work out cheaper to run once you've got over the shock of the initial cost as they are individually controlled. An electric boiler will heat all the rooms unless you run around turning them on and off.

tacpot12

As per matelotdave's comments, it should be a straight-forward replacement, but there are a lot of variables. At the end of the day, any boiler is just a pipe that cold water travels down in order to become hot (and where the heating can be turned on or off, or possibly modulated).

Heating controls are one area where things might be incompatible, or they might be fine.

greatcrested

My neighbour converted to an electric boiler and rates it highly.

I believe he re-did all the plumbing and rads.

But he's a rich b*gger and I think prefers the extra cost over the 'hassle' I have topping up my oil tank once a year.

I won't be followig his example...!

Ebe_Scrooge

I've got to agree with the previous comments - replacing an oil boiler with an electric one is, in principle, a straightforward "like-for-like" swap.  Well, obviously not like-for-like, but you get my drift :-) You'd probably need to factor in the cost of the appropriately-rated wiring, but other than that it's simple.  It would be a different matter if you were looking at ground-source or air-source heat pumps.

But I fail to see why anyone would consider this (with the exception of Greatcrested's rich friend!).  In the absence of mains gas, oil is just about the cheapest and most convenient alternative there is.

roddydogs

As you posted a similar thread in July, have you not found out yet?

Cardew

You don't say the size of your house. However most oil boilers are rated at around 30kW+ and can heat water up to 80C.

Whilst they only will use the full 30kW initially to heat a cold house and heat water in a tank(assuming not a combi) they have that output. I haven't seen a domestic electric boiler with an output above 15kW.

https://www.viessmann.co.uk/heating-advice/what-size-electric-boiler

The above link gives details of electric boiler sizing and states they are only suitable for small houses flats.

Bear in mind that Electrical regulations make it mandatory that heavy duty wiring and a suitable RCB are used when installing an electrical boiler - expensive in a retro-fit! 

drsquirrel

tacpot12 said:

As per matelotdave's comments, it should be a straight-forward replacement, but there are a lot of variables. At the end of the day, any boiler is just a pipe that cold water travels down in order to become hot (and where the heating can be turned on or off, or possibly modulated).

Heating controls are one area where things might be incompatible, or they might be fine.

I'm not versed in how electric boilers work in detail, im presuming they don't have (or need) any kind of condensing on them?

Since it seems that electric could heat one rad without problem whereas I am being told that with oil (and maybe gas) condensing boilers that this is an inefficient way run. So not modulated as such? All the farting around to get oil/gas heat into a pipe when an electric element or two stuck in the water flow sounds like that's all you'd need.

(I am about to post a thread posing some questions to this as I am looking for alternatives to backup solid fuel)

Ectophile

When it comes down to it, an electric boiler is just a big immersion heater and a pump to circulate the water.  They tend to be simple and reliable.

And extremely expensive to run.  A 9kW one might be around £1.50 an hour.

drsquirrel

Ectophile said:

When it comes down to it, an electric boiler is just a big immersion heater and a pump to circulate the water.  They tend to be simple and reliable.

And extremely expensive to run.  A 9kW one might be around £1.50 an hour.

I did some digging and found internal pictures of some models and indeed they are simple, can vary the output as well. Still doesn't mean they're cheap to buy though! a 12kW unit (with the self contained pump/expansion) £1,300. A similar sized gas combi is cheaper than that, you would think its more complex. I'm sure scale of sales affects it but electric have got to be cheap to make.
What I was trying to look at was, yes it might cost more, but the maintenance and such should be a lot lower, for a very low level user it might actually make sense. Doesn't help that the main units aren't actually that cheap.

tacpot12

If I needed 12KW of electric heating, I would check to see if installing two 6KW units might save money. You would also have some redundancy if one unit fails.