how much would i save? is it worth it?

COOLTRIKERCHICK

ok....

we have a coal fire which runs the hot water and central heating..

over the last few years we have been burning more wood in the fire to try and save money... as call has also gone up in price.

In the summer we leave the emersion heater on constantly.. as we found/thought it would be cheaper to leave it on all the time, rather than put it on when we want to heat the tank for hot water...( reason being its not heating up a full tank of water, but only keeping it to temp)

Now i am thinking, how much would i save, if i burned wood in the fire for an hour a night, to heat the water, rather than have the emersion on all the time?

we are only here during the day at the weekends, so i was thinking we could light the fire as soon as we come home from work... by hte time we had our cuppa etc, the water should be getting hot.

How much do you think we would save? ( wood is free) and is it worth it?

We got told that our electricity is going up by 11% at the end of August, we are with swalec and are on a pre-paid key ( we were thinking about changing this, but in all honesty even though we are paying a bit more for the electric.. it does save any nasty monthly/quarterly bills)

Pincher

COOLTRIKERCHICK wrote: »

How much do you think we would save? ( wood is free) and is it worth it?

What price convenience?

macman

COOLTRIKERCHICK wrote: »

ok....

we have a coal fire which runs the hot water and central heating..

over the last few years we have been burning more wood in the fire to try and save money... as call has also gone up in price.

In the summer we leave the emersion heater on constantly.. as we found/thought it would be cheaper to leave it on all the time, rather than put it on when we want to heat the tank for hot water...( reason being its not heating up a full tank of water, but only keeping it to temp)

Now i am thinking, how much would i save, if i burned wood in the fire for an hour a night, to heat the water, rather than have the emersion on all the time?

we are only here during the day at the weekends, so i was thinking we could light the fire as soon as we come home from work... by hte time we had our cuppa etc, the water should be getting hot.

How much do you think we would save? ( wood is free) and is it worth it?

We got told that our electricity is going up by 11% at the end of August, we are with swalec and are on a pre-paid key ( we were thinking about changing this, but in all honesty even though we are paying a bit more for the electric.. it does save any nasty monthly/quarterly bills)

This is completely wrong, and if you browse the forum you will find many others who were paying unnecessarily high bills because they didn't understand basic physics.
Do you leave your kettle on all the time because it will use less energy to make a cup of tea than boiling it from cold? Exactly the same principle.
The longer you leave your immersion on, the more it will cost you, end of story.

COOLTRIKERCHICK

thanks macman...

We just presume4d because the emersion was on a thermostat, ( i think)that once it hit a certain temp. it would switch off, and only kick in once the water went below a certain temp...so our way of thinking was it was cheaper to keep the emersion on, than it heat all the water in the tank from cold.

keith1950

Hi COOLTRIKERCHICK, everyone assumes that because the hot water tank is insulated keeping the immersion on at a set temperature will save money.

The point is, that to enable this, the insulation would have to be so good that there were no losses from the tank, so that once up to temperature the immersion would not switch on again until more water was used.

HappyMJ

COOLTRIKERCHICK wrote: »

thanks macman...

We just presume4d because the emersion was on a thermostat, ( i think)that once it hit a certain temp. it would switch off, and only kick in once the water went below a certain temp...so our way of thinking was it was cheaper to keep the emersion on, than it heat all the water in the tank from cold.

The amount of difference is small. If you leave the immersion on all the time it will as you say turn off and turn on as required. Maybe 2 minutes an hour to reheat the losses from the last hour. That will cost about 1.4 pennies per hour. If you made the immersion only come on for an hour in the morning and an hour in the evening it will reheat the losses from the last 11 hours. Maybe for about 20 minutes per time. At a cost of 28p per day. The annual difference to your bill will be about £20 more per year by leaving it on all the time. If you had an E7 meter the differences would be much larger maybe costing 10p per night at the cheap rate. The annual difference being £86.

The figures I have used are my own from my own tariff.

Premier_2

HappyMJ wrote: »

The amount of difference is small. If you leave the immersion on all the time it will as you say turn off and turn on as required. Maybe 2 minutes an hour to reheat the losses from the last hour. That will cost about 1.4 pennies per hour. If you made the immersion only come on for an hour in the morning and an hour in the evening it will reheat the losses from the last 11 hours. Maybe for about 20 minutes per time. At a cost of 28p per day. The annual difference to your bill will be about £20 more per year by leaving it on all the time. If you had an E7 meter the differences would be much larger maybe costing 10p per night at the cheap rate. The annual difference being £86.

The figures I have used are my own from my own tariff.

You must have an exceedingly well insulated hot water tank if you think 2 minutes per hour will keep the temperature up.

2 minutes @ 3000W is 100Wh - i.e. the same amount of energy an old fashioned 100W light bulb uses if left on. My airing cupboard (when the hot water is left on) is a lot warmer than a similar size cupboard with a light bulb on in it.

HappyMJ

Premier wrote: »

You must have an exceedingly well insulated hot water tank if you think 2 minutes per hour will keep the temperature up.

2 minutes @ 3000W is 100Wh - i.e. the same amount of energy an old fashioned 100W light bulb uses if left on. My airing cupboard (when the hot water is left on) is a lot warmer than a similar size cupboard with a light bulb on in it.

Yes it's about 100W per hour at 70 degrees. There are smaller well insulated water tanks that have a heat loss of 1kWh/24 hours. I'd say 2.4kWh/24 hours is a fair estimate to use.