Our gas-powered tankless on-demand water heater has packed up. (We do still have a great electric shower and separate gas central heating works lovely)

So if we invest in an electric water heater, (as my retired gas-man father-in-law suggests) how big a one will we need. Tankless electric is out of the question as you need big modifications to house electrics (as the curent is huuuge kw’s), so he is suggesting one with a tank. ‘We’ are 2 adults, 2 small kids and have a normal sized bath, and 2 other hot taps in the house and no plans for any more. As before, central heating and shower not an issue unless it would be better to replace 12-year old central heating boiler with a combi boiler.

Websites so far suggest 30-40 gallons which is about four times what f-i-l thinks we will need. ❓

Any advice please?

I’d look at the 12 year old boiler as a candidate for replacement in the next year or two – might be best to get quotes for replacing that with;

a) a combi
b) a traditional boiler.

and if you go for b) you might be abel to fit a tank/electric thing now and then add gas boiler heating the water later on if you tell the plumber in advance what you want to do?

you’re not going to get much of a bath out of 8 gallons of water?

you’re not going to get much of a bath out of 8 gallons of water?

…was my thought too. Assuming my favoured hot/cold ratio for baths which at very best is 3:2, a 3kw heater with 30l tank gives me 50 litres of just-about bath temp water in my 140l bathtub. And no more hot water for another couple of hours. Hmmmmm….

I agree with wwaswas. We moved into a place with a similar aged boiler and replaced it with a 28kw Bosch Worcester combi. Plenty of hot water for baths and now the heating actually works. We also gained some storage (where the hot water tank used to be). We have an electric shower btw.

It would be pain if you replaced the water heater and then your boiler goes down next year (which is likely given it’s age).

I’d also agree on the combi front. It does make an electric shower a little pointless (and, in fact, if the electric shower is pumped, you’ll have to put a dedicated tank in for it). Bath will fill slower than from a tank, but hot water will be available the whole time. I’d also think it’ll be cheaper to run, long term, than having two seperate devices heating things up

Thanks for your comments folks. Personally i think combi is the way forward, but funds may dictate electric hot water heater….

so where are we with hot water tank capacity? Is 30l ridiculous then? I can’t help thinking 100+l is more realistic.

surely once you’ve added in the cost of a tank, heating element, switch mechanism, plumbing to the tank, etc, you’ll be at the best part of the cost of a combi boiler anyway?? mine was only £1500 fitted..

plumbing/work cost not an issue as f-i-l will do all that, and place where we would put it is quite big well sited for easy plumbing using old pipes. Just that father-in-law thinks we will be fine with a 30l under/over sink type unit for much less money. Surely that is good for a couple of sinks worth of washing up, not a family bathroom?

get a combi will be dearer than an imeersion tank in fitting terms but over its lifetime it will save you more and is much more practical

Have you thought about putting a hot water cylinder where the existing gas powered water heater is and feed it from the boiler? There may be a good reason why not but it would seem a straightforward option especially if f-i-l can do the labour.

If a new boiler is out of the question on current cash terms then the 30l should be ok JUST for the sinks but then what do you do when you want a bath? Back to the old days of boiling kettles and pots of water on every ring of the cooker? 😀

Have you thought about putting a hot water cylinder where the existing gas powered water heater is and feed it from the boiler? There may be a good reason why not but it would seem a straightforward option especially if f-i-l can do the labour.

My thoughts exactly.

And as for size, we have a 250L Megaflo for 2 a family of 5 and I wouldn’t want anything smaller.

Unvented indirect hot water cylinder, only uses 3kW immersion heater, get one big enough and try to heat it on Economy 7. Then when funds permit connect it to the boiler. And as you are heating it electrically as big as you can get, 250litres should do it.

As above, go for the cheapest full stainless unvented cylinder you can get. You’ll probably get a 250 for around 600 quid. I recently fitted a kingspan flomaster, 180 litre, cost 485. I wouldn’t use one again though, the inlet is too high and it can’t be drained without suction.

Range are good value, fitted quite a few of those, everything is in the box ready.

I would forget the electric heater

Gledhill is my choice of cheap stainless unvented, Oso for the expensive taste. Used loads of Oso and had very little problem, and when I do the rep will visit and help, hence my liking of them. Fitted a few Gledhill for mates on a budget and have been impressed so far…