Best way to heat water Q

Mugser

Standard copper cylinder in the hot press with dual immersion element & single water coil fed from gas fried central heating with it's own zone motorized valve. Have a Sonoff switch with a temperature probe stuck in alongside the thermostat for the MV (roughly half way point on the tank), I've a hive system for the CH & HW and the ability to schedule and trigger either sink or bath element on the immersion with a zigbee switch and a non-priority box I made up using 2 NO and 2 NC 20A relays. (wiring diagram attached for anyone interested)
In summary so, I can, using IFTTT I can trigger the hive HW boost and/or the immersion to heat the water and set a max and min temperature on the eWelink app.
So, my questions; what temperature range would be recommended to maintain water for everyday use?, (currently set from 30 to 50 degs, which I think is about right.. top of tank would be warmer than that I know) also, am I better off using gas on its own or the immersion along with it, from an efficiency point of view? (i.e. both at same time)

loyatemu

Gas is cheaper than electricity. If your cylinder is properly insulated your best bet is just leave it on most/all the time unless you're away.

spaceHopper

run it on gas with a thermostat let the boiler take care of it. I've 300 lt tank I run the boiler for 1 hour a day at 5 am to heat it and we never run out of water

2011

Mugser wrote: »

Have a Sonoff switch with a temperature probe stuck in alongside the thermostat for the MV (roughly half way point on the tank)

I did something similar. Over time I worked out that when the sensor reads 27 degrees there is enough hot water in the tank for 2 showers. This means of course that the water at the top of the tank is far hotter.

I've a hive system for the CH & HW and the ability to schedule and trigger either sink or bath element on the immersion with a zigbee switch and a non-priority box I made up using 2 NO and 2 NC 20A relays.

Using normally closed contractors in this way is not advised as it means that in the event of an issue the load will fail on load rather than fail off load. That is why we generally select normally open contactors and relays for loads. I can't really follow your diagram but it would be best to ensure that there is a hard interlock that prevents both the sink and the bath immersion elements being on at the same time.

So, my questions; what temperature range would be recommended to maintain water for everyday use?, (currently set from 30 to 50 degs, which I think is about right.. top of tank would be warmer than that I know)

Just like me you will have to learn from trial and error. Obviously if you heat too much water it is wasteful and will increase your bill.

am I better off using gas on its own or the immersion along with it, from an efficiency point of view?

From a cost point of view heating water with gas is far cheaper as others have pointed out.

To keep your bills down you should avoid using the immersion altogether unless you have no other option.