Newbie Question - Water Heater on or off?

Sorry about the late relply Mike. It's as Jill says, 30 minutes would be ample time

Kerry

Can you explain please?

Me too, I'm very interested

OK here goes.

Anything that is hotter than its surroundings will dissipate heat into the atmosphere. You can lessen this with insulation but there is no such thing as 100% insulation.

The greater the temperature difference between the object and its surroundings the greater the heat dissipation will be.

The temperature of your hot water container will go down when it is switched off so will dissipate less heat at such times and therefore use less energy than if on all the time.

Basic rule of Physics is: Energy put in equals energy got out.

Having said that I never turn mine off when on site as the electricity price is fixed and I would probably forget to switch it back on in time.

I read Astro76's post on page 3 with a certain amount of disbelief!  But no one else has remarked on it!   Astro did you really mean to say that you are using grey water to top up your toilet flush????

Fine in theory but how long do you expect to be able to use the flush before something jams in the pipes and causes a blockage?   

The fact that no one else has commented on it suggests that Ive got hold of the wrong end of the flush!

TF

I saw that TF and wondered if he only showers into the aquaroll - my kitchen waste would not be good!  BUT seeing so many onsite who use watering cans to fill the loo flush - and LEAVe them under the caravan - I have seen the number of insects that collect in watering cans and they are BAD news!    I use an old 5 litre water bottle and keep the stopper firmly ON! 

I saw that TF and wondered if he only showers into the aquaroll - my kitchen waste would not be good!  BUT seeing so many onsite who use watering cans to fill the loo flush - and LEAVe them under the caravan - I have seen the number of insects that collect in watering cans and they are BAD news!    I use an old 5 litre water bottle and keep the stopper firmly ON! 

Pippah, I'm one of the watering can under the van brigade. I'm pleased to read your comment and now certainly see your point. I will put it away from now on.

Harry - I happened to notice a friend's watering can last year - it had about 30 beetles in it and a few other insects!  Mind you there was quite a lot of water in it too ready to fill the flush again. 

Can you explain please?

Me too, I'm very interested

OK here goes.

Anything that is hotter than its surroundings will dissipate heat into the atmosphere. You can lessen this with insulation but there is no such thing as 100% insulation.

The greater the temperature difference between the object and its surroundings the greater the heat dissipation will be.

The temperature of your hot water container will go down when it is switched off so will dissipate less heat at such times and therefore use less energy than if on all the time.

Basic rule of Physics is: Energy put in equals energy got out.

Having said that I never turn mine off when on site as the electricity price is fixed and I would probably forget to switch it back on in time.

We are discussing which costs the most, leaving it on relying on the insulation to keep it warm until the thermostat kicks in turning on the power for a short time verses turning it off and reheating from cold.

The laws of conservation of energy equally to both senarios.(We would be in trouble if it didn't)  But which uses the least power over a 24 hour period. Trials on domestic systems suggest leaving it on and the numbers get more convincing the better the insulation

As soon as we have put the water on and got the at through the taps, we switch on the water heater and it stops on until we leave the site.  That way we have hot water when we need it.

David

Can you explain please?

Me too, I'm very interested

OK here goes.

Anything that is hotter than its surroundings will dissipate heat into the atmosphere. You can lessen this with insulation but there is no such thing as 100% insulation.

The greater the temperature difference between the object and its surroundings the greater the heat dissipation will be.

The temperature of your hot water container will go down when it is switched off so will dissipate less heat at such times and therefore use less energy than if on all the time.

Basic rule of Physics is: Energy put in equals energy got out.

Having said that I never turn mine off when on site as the electricity price is fixed and I would probably forget to switch it back on in time.

We are discussing which costs the most, leaving it on relying on the insulation to keep it warm until the thermostat kicks in turning on the power for a short time verses turning it off and reheating from cold.

The laws of conservation of energy equally to both senarios.(We would be in trouble if it didn't)  But which uses the least power over a 24 hour period. Trials on domestic systems suggest leaving it on and the numbers get more convincing the better the insulation

That depends totally on how often it runs. This time of year our room heating comes on for half an hour twice a day. However the two rooms we use normally have the doors close dwhereas often back door is left open occasionally, 

The greater the temperature difference between the object and its surroundings the greater the heat dissipation will be.

If my memory serves me correct ( and it is a long time since my school days  ) this is "Newtons Law of Cooling"