"Dennis@home" wrote in message
web.com...
On 20/01/2015 17:13, Dave Plowman (News) wrote:
In article ,
harryagain wrote:

"Dave Liquorice" wrote in message
ll.co.uk...
On Tue, 20 Jan 2015 09:18:19 -0000, harryagain wrote:

The big debate with hot water storage vessels in Summer is "Is it
cheaper to turn on the CH or use an immersion heater?"

Why would one turn on the CH to heat the HW? Something very wrong
with the control system if you have to do that.

Costs? Gas 5p/unit 80% effcient = 6.25p lecky is 10p/unit or more...

The debate is about heating a boiler, water and pipework (plus losses
from pipework) up from cold to get a bit of hot water as compared with
just heating the water in the HW store with the immersion heater.

I doubt many would be happy with 'a bit of hot water' given most
households will use pretty well the same amount regardless of season. So
you'd let either the boiler or the immersion heat the full tank - same as
usual.

If the boiler is already running for heating the house then obviously
it's cheaper to use it. But in Summer the economics are questionable.

Don't agree they are. You'd need enormous losses in the pipework to the
cylinder. Modern boilers contain very little water and heat quickly.



You would think that an expert like harry would have insulation on the
circuits anyway. Mine has 35 mm of foam around all the primary circuit and
quite a lot of the heating.

You forget ****-fer-brains that my house needs no central heating system at
all.
When I need hot water it is all by electricity and heated within 300mm of
the point of use.
The electricity is mostly from the PV system.