Combi or stored hot water

jull_2

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penrhyn

If your boiler fairly modern and your tank well insulated?
If so I doubt the cost will be much different, might take you longer to fill the bath.

Cardew

Well for a start you couldn't hope to run a power shower* from a combi, the flow is not sufficient.

A modern well insulated HW tank will lose about 2kWh in 24 hours with water at 65C(they are tested to a British standard. So as you would not have a full tank of Hot water all the time, you would lose less than that, possibly 1kWh a day.

Also that 'lost' heat isn't really lost as it warms up the fabric of the house - which is why HW tanks are normally in airing cupboards.

So in practice the saving of a combi over a conventional boiler with a HW tank are not high. Impossible to give accurate figures, and another factor is the length of HW pipe runs.

* Many people on MSE use the term 'power shower' when they mean 'Electric shower'. A power shower uses HW from a HW tank and the flow is boosted to a high pressure by a pump; and they use lots of HW.

C_Mababejive

Stick with the hot water tank. Just make sure you have good insulation,good heating controls etc etc

macman

Given your incredibly low gas consumption (£20pm), what is the point in changing your boiler as long as it is working? Even if it were 20% more efficient, it would still take you around 30 years to recover the outlay.

macman

Sounds like it's kettling due to scale build up in the heat exchanger. Why don't you just get it serviced and apply some descaler instead?
The flue should be sorted immediately out if corroded, as potentially lethal-but it doesn't necessarily require a new boiler.

gas4you

From what you have been told so far by BG it does sound like you need a need boiler. But the question is have you been told the truth?

BG are notorious for scaremongering to get a new boiler installation.

How did the BG engineer now your flue liner is corroded without being able to inspect it visually.

I have removed some flue liners that have corroded, but not that many in the big picture.

Descaling your boiler will work for 1-2 years then it will be back and it also could find a weakness with the heat exchanger and create a leak.

Because you use so little gas now your saving with a new boiler will not be as much as someone who uses loads of gas.

If your hot water use is low and there are only 2 of you, then a combi could be a good solution for you in this case.

You need a good and trusted engineer on site to advise you properly.

Cardew

Seems there are two issues here:

Firstly the advisability of replacing an old but working boiler.

Secondly, if a replacement is the chosen solution, should it be a combi or a conventional boiler feeding HW to a tank.

On the first issue, I think many on here would advocate keeping it going as long as possible; the savings in running cost, especially on you low consumption, would be small.

Secondly, my firm preference is for a conventional boiler for the reasons explained in post#3

penrhyn

Strange noises when you turn on the hot tap: If its a stored water system i can't see what this has to do with the boiler, more likely that the cold tank is not filling quickly enough.
IIWY I'd invest £20 in a tube of boiler silencer gel and inject it in one of your radiators and see what effect that has over a couple of weeks.

penrhyn

You don't have radiators? So why would you want a combination boiler?

macman

D'oh!
Oh well, at least that explains the tiny gas consumption...