On 12/03/2018 10:54, Dan S. MacAbre wrote:

Now that the weather is warming up, I'm considering replacing our HW
storage tank (it's about 30 years old, and is getting a bit crusty
around some of the pipe connectors). Before I do, I suppose I ought to
ask if (in everyone's opinion) I should just replace it like-for-like?
Or is there some other direction I ought to be heading in, like
mains-pressure hot water, or just using instant hot-water taps
everywhere instead? Or something else?

If you are keeping the current boiler, then your options basically come
down to either stored hot water, or some kind of thermal store / heat
bank arrangement.

The setup you have now is simple enough and can work well - however it
has pros and cons and does not suit all properties or usage patterns.

An unvented cylinder will adds a bit of complexity close to the cylinder
- but does away with the need for a cistern in the loft. It has the
advantage of delivering mains pressure (or close to it water to all the
hot taps - so good for showers without the need for pumps etc). You can
still have an immersion backup. To work well though you would need to
make sure you have a decent flow rate from your mains cold supply.

Have a look at the lists of pros/cons etc he

http://wiki.diyfaq.org.uk/index.php/Unvented_DHW

The thermal store options are similar - basically a big tank of hot
water - however its used indirectly to heat the incoming cold water on
demand. A slightly different set of pro's an cons, but handy for example
if you want to incorporate several heat sources like solid fuel and
solar as well as a boiler / immersion.

http://wiki.diyfaq.org.uk/index.php/...and_Heat_Banks

You can buy them ready to go or cobble one together from parts:

http://wiki.diyfaq.org.uk/index.php/DIY_Heat_Bank





--
Cheers,

John.

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