Hot water immersion left on 24h's

[trevorbayliss]

Does anyone know if leaving on an unvented hot water immersion 24h's a day is poor economically compared to using a timer ?

I have a new gledhill 150L cylinder and we were thinking it would be fine to just leave it on all the time. The reason being is that the cylinder will self regulate and cut out when it gets to a certain temp. The heatloss per 24h is low so is there an issue ? I spoke to the tech people and they said it was designed to work like this, but I've been reading some stories about people who have very high bills from running their immersions.

My set up is one element only, no boost.

I do have a timer, but wasnt planning to make use of it. I suppose i will find out for myself what the bills will be like, but thought i would ask on here what peoples experiences are. Looking at using 2 showers per day plus maybe some HW for washing bits in the kitchen sink, but we will use a dish washer mostly.

 

[Harry Bloomfield]

Left on, due to heat loss, it will cost more than if it were just brought to temperature just before it is needed. How much you might be able to save, depends upon the level of heat loss. The best way to measure it, is to measure the consumption for a full 24 hours, beginning a few hours after it has settled at temperature, with no hot water used for the entire 24 hour period.

 

[JohnD]

Does anyone know if leaving on an unvented hot water immersion 24h's a day is poor economically compared to using a timer ?

I have a new gledhill 150L cylinder and we were thinking it would be fine to just leave it on all the time. The reason being is that the cylinder will self regulate and cut out when it gets to a certain temp. The heatloss per 24h is low so is there an issue ? I spoke to the tech people and they said it was designed to work like this, but I've been reading some stories about people who have very high bills from running their immersions.

My set up is one element only, no boost.

I do have a timer, but wasnt planning to make use of it. I suppose i will find out for myself what the bills will be like, but thought i would ask on here what peoples experiences are. Looking at using 2 showers per day plus maybe some HW for washing bits in the kitchen sink, but we will use a dish washer mostly.

If it is fully hot, about 1.5kWh per day of heat will leak out to warm your airing cupboard and your house. I don't know your tariff. My electricity costs about 15p per kWh, I believe the capped tariff is about 32p

If you reduce the average amount of stored hot water by 10%, I suppose you will save a few pence a day.

Do you have any scope to heat the cylinder with gas, or with off-peak electricity? Either would be much cheaper.

 

[trevorbayliss]

No I can’t heat with gas or off peak electric. Kw price after April time is going to be about 50p kw. Currently I pay 34kw. Old fixed rates of 15p are long gone for many.

I think having read various experiences on the net I need to heat for 2h in the morning and do a one hour top up in the eve. I think that should be better than being on constantly

 

[JohnD]

Insulate any exposed HW pipes, especially any going upwards from the cylinder, will also reduce losses.

 

[Old Salt]

With all energy costs the best way to work out which is the best method for you is to take a meter reading, run the system for a couple of days, take a further reading. Make your changes then take another reading. Run the system again for a couple of days and then take a reading. It doesn't matter whether its gas, electric or oil, boilers, lighting, hot water or anything else.

Work out which way works best for you. The only provisio is that the environment needs to be roughly equal for both set ups. So similar usage, ambient temperatures, weather conditions etc. You can make as many alterations as you want until you settle on what works for you.

Remember its not only the cost, you need to take into account but convenience as well.