Water Heating Question

[Doctor Evil]

You mean by the know-it-all bunch of armatures. I'm pro in the game . Read, listen learn. Nah you are incapable of learning.

What drivel!

[Doctor Evil]

I hope you are only being polite, as the advice was not useful.

[Doctor Evil]

Firstly, find out what the flow rate is. Time filling a bucket at the outside tap. If that is OK, then it will be just a mater of running separate cold supplies from the stop c*ck. One direct to the combi(s) inlet and one to the cold taps. The cold to the showers can be taken off the appropriate combi cold supply, teed off just before the combi. This limits pressure fluctuations around the combi, and will reduce effects on the showers..

[Doctor Evil]

Or just add another combi and spit the outlets amongst the combis. Musch simpler and cheaper.

[Doctor Evil]

Oh my God, here we go again.

[Doctor Evil]

Jerys latest post summed you up right.

..two combi's is the favoured choice ..a solution our snotty uni man did not voice ..the combi's shower all for ever more ..with no large cylinders in which to store ..the cylinders cost a pretty penny ..the two combi's cost hardly any

..experience of these matters of his is slight ..taking notice of him the silly they might.

..cheap showers are there for ever more ..by use two combi's and not a cylinder water store.

[Doctor Evil]

Do you have any figures to prove this half baked theory? Or have you just made it up as usual?

[Andy Hall]

A moot point since most fabrics and detergents use washes that are so cool that little or no hot water is used anyway.

Yet another instance of focussing on the corner cases and missing the plot.

[Doctor Evil]

Depends on the machine. Many take more hot water from the hot draw-off than others. Even if a machine only occasionally takes in hot water it is still well worth it as electricity is 4 times more expensive. That is a hell of a difference.

Some dishwashers can be hot or cold fill. Best hot, as it is still cheaper even though the rise is on hot.

[Christian McArdle]

Which drops to nothing, or even negative when the wash fill is only a few litres, which is probably greater than the amount of cold water that is required to be flushed from the supply line.

If you have a water meter, the cost of the wasted water may be at least as significant as the heating costs.

Yes electricity costs 3 to 4 times as much. However, the electrically heated system will be considerably more efficient, mitigating or even reversing this.

Hot fill dishwashers do not clean as effectively as cold fill. Hot fill ones use considerably more energy, as any rinsing cycles are done with hot water, rather than cold. The supply pipes get hot and cool down several times in the cycle, leading to much greater parasitic losses. That is why every single 'A' rated energy efficiency dishwasher has cold fill.

Christian.

[Doctor Evil]

Over a year it is not nothing, it all adds up.

You can have a secondary circulation pump to give instant hot water at the taps, and cut down on dead leg wastage all around. It is also nicer to have instant water at the taps.

Nonsense.

As gas heated water is 1/4 of the price, it is still cheaper.

Can be eliminated by using a secondary circulation pump.

The A rating is way out of date, as most modern machines now meet it easily enough. The most efficient appliances was way off the scale making the scale meaningless and confusing.

Efficiency does not relate to cost of running. As electricity is 4 times more expensive to run than gas, an appliance using gas to heat the water that is half as "efficient" as an all electric appliance is still cheaper to run. Also as electricity is dirty to produce with only 30% efficiency from station to point of use, the so-called "inefficient" gas using appliances also far cleaner. Get it?

[Christian McArdle]

Er, this helps save water, but means that the leg is constantly losing heat, so is bad for energy efficiency.

Christian.

[Dave Plowman (News)]

And just how is this going to get round the problem of other taps in the house - hot or cold - interacting with hot flow?

The usual IMM one size fits all answer to a question he hasn't understood.

[Dave Plowman (News)]

I'm quite sure you stand beside your washing machine while it does a cold pre-wash, then switch it off, run your twin 'combi's' both up to speed - making sure the temperature is exactly as same as the machine setting - then switch it on so you can save pence.

And I'm sure you'd fit the boiler as close to the machine as possible or vice versa. Regardless of anything else.

Any other pearls of wisdom?

[Aidan]

We're armatures?

I'm sure you are, I just can't imagine what that game might be. Can't involve motors.

[Dave Plowman (News)]

You'd be hard pressed to find a decent make new washing machine in the UK that is not cold fill only these days.

Unless you love those Merkin top loader things that waste half the world's resources.

Even more so with dishwashers.

Do you actually have either? If so, give the makes so we can all have a good laugh.

[Dave Plowman (News)]

Don't be silly. Drivel believes gas boilers are over 100% efficient.

[Doctor Evil]

You have the loop heavily lagged. It is also a great convenience too, to have instant water at the taps. Water is not cheap these days, so saving 2 to 3 litres per hand wash is highly economical.

[Doctor Evil]

Read what I wrote. I can't be bothered to explain to you as you lack comprehension.

[Doctor Evil]

No. I have a secondary circulation loop, so hot water is at every tap instantly.