Don't use a lot of hot water - immersion or boiler?

Betts

Hi, we are a family of 2 adults and 3 children with an old style boiler with a hot water tank. There is an immersion as back up but we have only lived in the house for a month and haven't used it yet. We are on economy 7 dual fuel with Robin Hood energy so Electricity night rate is 6.203 pkwh and gas is 3.062 pkwh.

At the moment our hot water is set to come on for a couple of hours in the morning, an hour in the afternoon and a couple of hours in the evening as this is how the last family had it programmed. Could anyone advise me as to what might suit us better and be more cost efficient? I'm used to a combi-boiler so don't really understand how long water stays hot for etc.

I don't bath my kids every day - maybe twice a week, we have a dishwasher so don't use hot water for washing up, we obviously wash ourselves but only have a shower or bath every other day so I don't think we are particularly high uses of hot water despite being a large family. I feel we are probably heating hot water we never use at the moment.

What would work best for us? using the immersion over night on economy 7 regardless of whether we are going to use the water? keeping the current boiler hot water settings? tweaking the boiler hot water settings (if so to what?)? or just using the boiler control's hot water advance button before we know we want to run a bath?

Sorry for the ignorance!
Thanks for any help

Betts

HappyMJ

Betts wrote: »

Hi, we are a family of 2 adults and 3 children with an old style boiler with a hot water tank. There is an immersion as back up but we have only lived in the house for a month and haven't used it yet. We are on economy 7 dual fuel with Robin Hood energy so Electricity night rate is 6.203 pkwh and gas is 3.062 pkwh.

At the moment our hot water is set to come on for a couple of hours in the morning, an hour in the afternoon and a couple of hours in the evening as this is how the last family had it programmed. Could anyone advise me as to what might suit us better and be more cost efficient? I'm used to a combi-boiler so don't really understand how long water stays hot for etc.

I don't bath my kids every day - maybe twice a week, we have a dishwasher so don't use hot water for washing up, we obviously wash ourselves but only have a shower or bath every other day so I don't think we are particularly high uses of hot water despite being a large family. I feel we are probably heating hot water we never use at the moment.

What would work best for us? using the immersion over night on economy 7 regardless of whether we are going to use the water? keeping the current boiler hot water settings? tweaking the boiler hot water settings (if so to what?)? or just using the boiler control's hot water advance button before we know we want to run a bath?

Sorry for the ignorance!
Thanks for any help

Betts

Me personally...

If this were my house...

I'd switch the E7 electricity tariff to a Standard tariff.

I would set the boiler to heat the water 24 hours a day. As soon as the water reaches the set temperature the boiler will turn off. When you have a bath and half the hot water is used the boiler will come on again and reheat the cylinder and it won't reheat until it's either been used or has lost enough temperature.

You can time it if you want but you run the risk of running out of hot water and having to wait an hour for more hot water. We all should wash our hands in warm water and soap after going to the toilet so running the risk of running out of hot water isn't recommended. You could wash your hands with an anti-bacterial soap under cold water.

The savings made by having timed hot water is small.

By the way this is not an "old-style" boiler. It's actually my preferred boiler choice. I don't like combi-boilers myself. There's no backup with a combi. If the boiler breaks down all you need to do now is turn the immersion on and wait for an engineer to call when they're ready. You will never have an emergency call out as you can wait.

If you've got a well insulated cylinder the water stays hot for 24 hours and stays warm for days.

matelodave

A lot depends on when you use your hot water and how well insulated your tank is.

Everytime the boiler kicks on and off it's trying to heat the tank and all the pipework between it and the tank, so it's probably only around 50% efficient so if you leave it on all day then you are wasting energy by keep topping up the tank temperature. This may be of benefit during the winter but not in the summer.

In my opinion you'd be better off working out when you use hot water and then making sure that the boiler comes on for enough time to heat sufficient water for your use - there's no advantage in keeping the tank hot all night but you need hot water when you get up so just have the boiler come on for an hour or so before you get up and perhaps an hour or so before your night time ablutions - if you run out then extend the on time a bit. You probably don't need boiling hot water during the day so it can cool down a bit before the evening reheat.

There's probably no benefit in having E7, especially if the day rate is significantly more expensive than a single rate tariff unless you can do your dishwashing, clothes washing & drying (if you use a tumble dryer) during the off peak period (ironing & vacuuming at night would also maximise your off peak use)

cranford

I am on E7 and use an immersion heater as my only water heating. Just the two of us but my night use is 4kwh (about 25p on your tarriff) for a 80x40 cm tank and some erergy for a freezer and fridge/freezer. I have a very hot setting and no need apart from the odd occasion to use the immersion heater during the day. Day use of one hour could easily be 2 kwhs or another 25p on a typical tarriff.
Having said that we have stopped tumble drying at night and have switched to a single day and night rate of 10.22 with AVRO energy and my bill will be cheaper than my previous fixed rate.. I believe that EON also do a single rate for a E7 meter

usefulmale

Like you, we are 2 adults and 3 children. Everyone has a bath twice weekly. We just used to switch our immersion on an hour before the first bath and then switched it off after the last bath. We just boil a kettle for hot water for doing the washing up.

cajef

HappyMJ wrote: »

There's no backup with a combi.

Yes there is it is called a kettle.

matelodave

usefulmale wrote: »

Like you, we are 2 adults and 3 children. Everyone has a bath twice weekly. We just used to switch our immersion on an hour before the first bath and then switched it off after the last bath. We just boil a kettle for hot water for doing the washing up.

surely the optimum would be to switch it off before the last bath otherwise you end up with a tank of hot water that slowly gets cold overnight unless it's very well lagged and gives you sufficient hot water for your morning ablutions.

tiger_eyes

You could always take the trial-and-error approach and start cutting down bit by bit on the heating time until you find you're running out of hot water every evening. Then you'll know how many hours a day you need.

[Deleted User]

HappyMJ wrote: »

There's no backup with a combi.

Yes there is, electric shower to get washed with and kettle to wash dishes with.

No need to rush and get a emergency call out.

usefulmale

matelodave wrote: »

surely the optimum would be to switch it off before the last bath otherwise you end up with a tank of hot water that slowly gets cold overnight unless it's very well lagged and gives you sufficient hot water for your morning ablutions.

Yes, it did sometimes get switched off before the last bath but hey, nobody's perfect.

The tank was very well lagged and often, the water was still hot enough for the morning facewashes.

rokwarm

Yes there is, electric shower to get washed with and kettle to wash dishes with.