Hot water tank/heating system, how does it work?

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Fingers crossed we should be exchanging soon. The house we are moving to has a conventional boiler and water tanks and I have only ever used combi boilers.

how do I use this system for hot water ?
I know the hot water tanks need to be heated , is this on and heated all day?

OH has a shower about 3am before work, Eldest DD has a shower around 7am, 2 youngest have a bath around 6pm, OH has another shower after work at around 7/8pm and I shower about 9/10pm (sometimes 7am ,sometimes both) .

Is the timing of our showers irrelevant or would I need to set it up to heat at all of those different times?

any tips for the best way to use welcome! Thanks!

You can leave the heating on all day but it is a waste of money (depending on how well your tank is insulated).

The most efficient way to use hot water with a tank is generate it just before you want to use it, then use it all. Then leave the tank cold until you next want to use it.

It normally takes about 1/2 hour to heat up a full tank.

If you're 3am time is correct then I would switch it on for 1/2 hour before 3am which should do for the morning, and then 1/2 hour at 5.30 pm.

But a lot of it will be about how big the tank is, and how well insulated it is. Modern tanks lose hardly any heat, so any water not used in the previous cycle will still be at the very least warm.

You probably won't save that much money messing around turning it on and off from leaving it on all the time between 6pm and 6am if the tank is well insulated, and remember that any heat in the water escapes into the house anyway in winter, so it is not wasted.

You will just need to experiment. The key thing to remember is if you screw up and there is no hot water, you should be only 1/2 hour away from getting some.

Heating the hot water tank is expensive. You also need to be aware that if you use all the hot water in the tank, you are suddenly going to find yourself in a cold shower. How many showers per tank is going to depend on the size of the tank and the length/heat of the shower - ours can do 2.

You will need to experiment but heating it ready for 3 am and ready for 6pm might be enough.

In winter you may need more as the tank refills with icy water so the second shower can be a bit cold.

We had to replace a combi with a tank when we refurbed our house. It's a large tank. It gets heated twice a day (5am and 5pm). It's well insulated though, so for example, if the water from 5am hasn't been used, it'll still be at quite a high temperature at 5pm, so won't take long to get to temperature. I was worried that I'd run out of hot water but been in over a year now and haven't yet. Our house is fairly large and has 3 storeys (the previous owners didn't have heating or hot water on the 2nd floor, so a combi worked OK for them, we've added it) and combis don't tend to be powerful enough, hence the tank (and pressure pump).

The boiler heats water in the tank. You need to check the capacity but most will last 2 showers before running cold. A full tank stays warm all day, but as you use it it tops up with cold. Just set the timer to heat up just before the bath until it can reheat afterwards, then again boost in the morning before the shower.

Thank you everyone !
OH is the one that generally has the very long hot showers but day to day these tend to be at least a couple of hours before anybody else will use the shower so hopefully that won’t be as much of an issue , we will upgrade the boiler at some point as it’s around 25-30 years old.

Are the showers electric showers or do they run off the hot water cylinder? We have electric showers so they heat their own water.

As we only need hot water for dishes and the odd bath our hot water is only on for 1 hour per day.

Is the shower definitely running off the tank? Most showers are separate IME.

I was recently told that combis are only really ok for small requirements or households with one bathroom. They seem to be on the way out as a concept. The one you have is probably quite efficient.

The tanks in your loft are feeder tanks for the hot water cylinder and the central heating. Do you have a hot water cylinder in a cupboard somewhere?

Not all showers run off the hot water cylinder so it depends whether they have electric showers or not as to whether you need the hot water on for longer.

We kept conventional boiler system when we got our new boiler, rather than getting a combi, as we have 3 bathrooms (bathroom, ensuite and downstairs toilet) and think it can affect water flow/temperature if all are used at once

Can they be put on timers? Asking for my own conventional system.

I find that because ours is pretty new, and well insulated, that the water stays hot for ages. It comes on for half hour in morning and half hour in evening to accommodate morning and evening showers and kids bath and that’s enough for our household at the moment as we don’t tend to be in them that long. (2 adults 2 primary ages kids). I managed to switch off the boiler once and we didn’t notice til the next day as the water in the tank was still pretty hot.

I usually put it on boost for about half an hour if we have guests or I occasionally want to have a nice hot bath, as it won’t be hot enough for that, especially if the kids have had a bath already.

The insulation on a new tank is pretty good. I just did the calculation on my tank.

So it would be 12C less (53C) a day after you had heated it to 65C. That assumes you hadn't taken any water out of course.

If I kept it on 24/7 at 65C I would lose about 15p a day I reckon. So that is the maximum amount of money I could possibly save in switching on and off for when I only needed it (and in reality I would probably only recover a fraction of this, and it is only in the summer that it is "lost" heat).

Of course it would also wear your boiler out faster so that is worth a fair amount.

If the hot tank isn't well insulated you can put a secondary cover on it.

We have a hot water tank. It’s on 24/7. It’s brand new, but replaced old system of the same. Neither had off switches.

Ours is 500l. It’s easily enough for 8 showers+ all one after the other.
We have three showers and one bath, and all can be going at once fine.

I wouldn’t bother turning it off.