Efficiency of heating hot water?

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Silly Car
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Efficiency of heating hot water?

Post by Silly Car »

Just musing st the moment...

Large household with 5 adults all showering daily has led to a number of occasions where I have ended up with a cold shower as I’m typically the last up / last to get showered after a day’s toil.

Hot water is supplied by massive (250l) fully insulated hot water tank fed from a conventional gas boiler with a digital thermostat and two port valve controlling it.

What would the pitfalls be of having the hot water set to run continuously throughout the day, clearly still controlled by the thermostat, so that the system heats up the water as it is used rather than at set times (or when boosted)?

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Re: Efficiency of heating hot water?

Post by David »

We do that withbour current condensing boiler and have even with stored systems. I doubt you would see much change in your bills...the argument is that its easier to keep it warm than heat it from cold. You can still use all the eater though...moght be easier to kill one or two of the other users.

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Re: Efficiency of heating hot water?

Post by Silly Car »

David wrote:
Wed Jun 17, 2020 4:52 pm
We do that withbour current condensing boiler and have even with stored systems. I doubt you would see much change in your bills...the argument is that its easier to keep it warm than heat it from cold. You can still use all the eater though...moght be easier to kill one or two of the other users.
Given the due lack oF consideration by one or two of the occupants*, the issue may naturally resolve itself when they (in)voluntarily move out...

In respect of the water, that was along my thoughts, we are heating the same amount of cold water, it would just happening as the tank is replenished rather than at fixed times throughout the day.

*namely the daughters rather than the daughter’s boyfriend or the wife.

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Re: Efficiency of heating hot water?

Post by Horse »

MSE says:

True or false? The energy mythbuster
We hear a lot of suggestions for saving energy that are simply not true. Here are some of them ...
It’s better to leave the hot water heater on all the time, rather than turning it on and off.
This is a very common myth. But in fact, you really don’t need to be heating your water all the time. Your immersion heater or boiler will heat up hot water which is stored in a tank. As long as the tank has a good insulating jacket, it will keep the water hot all day, without needing to be constantly reheated.

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Re: Efficiency of heating hot water?

Post by David »

But then a teenager stands in the shower till its all gone....

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Re: Efficiency of heating hot water?

Post by Horse »

David wrote:
Thu Jun 18, 2020 8:08 am
But then a teenager stands in the shower till its all gone....
We have a gas combi boiler - so 'endless hot water' and an electric shower. Sorted :)

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Re: Efficiency of heating hot water?

Post by iansoady »

Shower every day? What a waste of water......
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Re: Efficiency of heating hot water?

Post by Silly Car »

David wrote:
Thu Jun 18, 2020 8:08 am
But then a teenager stands in the shower till its all gone....
That is exactly the problem, all of the ‘kids’ (aged 23) are used to combi boilers / electric shower so never:

A. Think that the hot water might run out
B. Think about letting ‘the grown ups’ know they’ve used the last of the hot water

The latter is the greater piss boiler (DYSWIDT?)

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Re: Efficiency of heating hot water?

Post by Mussels »

The only downside to leaving the water on is that boilers are less efficient while they heat up so frequent stop starts will use a bit more gas than heating the whole tank in one go.
Given the amount of hot water you go through in a day I doubt you'd notice any difference in your bills.