Hot Water and Heating or Hot Water alone?

alijk1989

Hi,

I have had a google for an answer to this question but can't seem to see one. I am in a rented property (students) so changing the old boiler isn't an option but I have a question about cost.

At the moment we have the timer on for hot water only, twice a day, for an hour. The timer is one of the old ones with small plastic triggers that flick the hot water on and off.

With this system you can have the hot water on, on its own but you can only have the heating on if the hot water is also on. I am just wondering, some what naively I imagine, if having the heating on will actually increase the cost if its on at exactly the same time as the water? i.e. The boiler won't be on heating water for any longer.

The boiler heats water into a big storage tank as I can see if that's any use.

Thanks in Advance!

macman

Yes it will cost much more, because you are heating both the hot water in the tank and the hot water supplying the CH circuit, so the boiler will run for much longer. The boiler only fires in response to a call for heat either from the tank 'stat or the room 'stat-it doesn't run all the time that the timer is 'on'. Space heating will cost you much more than hot water heating.
If the tank is properly lagged then it will retain it's heat for many hours.

Cardew

As you say your hopes are somewhat naive.

When you put on heating, you are simply selecting more water to heat, i.e two separate 'systems'.

The hot water from the boiler is a common supply, but it splits so the HW tank is heated by one 'loop'(circuit) of water, and the radiators by another 'loop' of water.

As the 'loop' of water in the radiators cools much more quickly - it takes far more gas to heat in winter than the tank hot water loop.

Pincher

alijk1989 wrote: »

I am in a rented property (students) so changing the old boiler isn't an option but I have a question about cost.

Science or humanities?

If you are a science student, just remember your conservation of energy. If you still believe wishful thinking can create extra heat, you should seriously consider a career in advertising. Go faster stripes can boost your speed1 by 10%!

Foot Note 1: Perceived speed.

bengasman

alijk1989 wrote: »

I am just wondering, some what naively I imagine, if having the heating on will actually increase the cost if its on at exactly the same time as the water? i.e. The boiler won't be on heating water for any longer.

Of course it will be on longer and use more gas, it's like hanging a trailer behind a car.
What is it you study?

macman

Not physics I hope.