boiler/hot water tank and timmers ??

paulmapp8306

Linked to my "which shower" Post, id like clarification of how things work er boilers/hot water tanks/timers.

I currently have my timer on so I get an hours hot water from 7-8 in the morning. This gives me hot water through the day should I need it (for kitchen cleaning etc) and leaves enough for a bath in the afternoon/evening (the kids usually every few days rather than a shower - but me or the wife occasionally).

If I go for a pressurised tank to allow a shower bar and big bath (in a bathroom upgrade) Ill need hot water more often (for all the showers) - but how does the whole system work.

for instance, If I change the hot water times to 12 hours, will the boiler be running for 12 hours OR will it only run when some hot water is used (ie heating up the replacement water). Will the boiler run if the water in the tank cools (ie none gets used in one day).

Never really thought of this before - but from an economic POV I dont want hot water "on" all day BUT if I go for a pressurised tank and shower bar, Ill need a higher/more reliable availability of hot water against how I currenty do things (as my current shower is electric, and the low use of hot water elsewhere). If it only "costs" to refill the tank - then its much less of an issue I guess.