Cost of leaving the Immersion on per hour?

vicwatson

Sorry if wrong thread, I guess it is an environmental issue and I couldn't find a thread for "electricity costs" but does anyone know what it costs per hour when Immersion is on full ?

TIA

Capt'n Midnight

It's about 18c per KWhr

I don't know your immersion rating but if you check the immersion's rating should be on it probably 3 - 7.5Kw
7.5Kw x 1 hour works out at ~ €1.35

not sure about sink/bath switch - the sink only heats the top of the tank so termostat turns it off sooner, also not sure if it's uses a lower wattage

Daegerty

You can get different elements for an immersion and they don't all have the bath/sink

My one for a 90 litre tank is 2 or 2.2kw for Bath, 2.8kw for Sink.

On Sink it would probably not even stay on for a full hour before thermostat switches it off at around 60 degrees.

So maybe 35c per hour when it's cold and maybe 10-15c every hour after that you're only replacing heat thats lost to the surroundings

7.5kW immersion would be for a massive tank not really the common every day ones you see around the place

vicwatson

Cheers lads, the tank is hard to get at but its about 2 metres high (don't know litres).

Is there a thing I can but to replace the on/off switch to put a thermostat or a switch that will knock off automatically? Forever forgetting to switch it off and it's costing me a fortune !

Do all immersions have an auto cut off? I don't think mine does anyway.

Cheers

Capt'n Midnight

Daegerty wrote: »

So maybe 35c per hour when it's cold and maybe 10-15c every hour after that you're only replacing heat thats lost to the surroundings

getting an extra lagging jacket is well worth it. It means you can have lukewarm water for twice as long.

7.5kW immersion would be for a massive tank not really the common every day ones you see around the place

worst case

yeah 2.8Kw sounds more like it all right

Daegerty

vicwatson wrote: »

Cheers lads, the tank is hard to get at but its about 2 metres high (don't know litres).

Is there a thing I can but to replace the on/off switch to put a thermostat or a switch that will knock off automatically? Forever forgetting to switch it off and it's costing me a fortune !

Do all immersions have an auto cut off? I don't think mine does anyway.

Cheers

Not all of them I'd say. If it has a thermostat it would be even harder to get at. Twould be in the little box that mains wire goes to the immersion. You'd have to open that up to check. The thermostat itself is a stick about 8" long that goes into a little tube inside that box.

Even if the little tube isn't there you can put in a new element (one that has the sink & bath function) and that would also have the tube for the thermostat. The thermostat can be got seperately for about 25e we had to get a new one once. There would be a little screwhole on top of it where you can adjust the temperature.

Failing that you can get a timer for the immersion that will have a 'boost' button to give it a quick blast for half an hour before ya take a bath. These are often used for night rate electricity so it switches on in the morning or when the night rate comes in

rayh

vicwatson wrote: »

Sorry if wrong thread, I guess it is an environmental issue and I couldn't find a thread for "electricity costs" but does anyone know what it costs per hour when Immersion is on full ?

TIA

Can I suggest that the issue is not the size of the tank or the element rating. Its the amount of water and the temperature through which you have to raise its temperature and when you have raised the temperature, the amount of heat which is then lost through poor insulation of the tank and its attendand pipework.
Electric elements are almost 100% efficient in converting electric energy to heat, so the rating will only effect the time it takes to heat the water, so therefore you cost per hour will be a function of 4 factors (1) Element Rating. (2) Timeperature rise. (3) Water Usage. (4) Heat loss from system.

Daegerty

rayh wrote: »

Can I suggest that the issue is not the size of the tank or the element rating. Its the amount of water and the temperature through which you have to raise its temperature and when you have raised the temperature, the amount of heat which is then lost through poor insulation of the tank and its attendand pipework.
Electric elements are almost 100% efficient in converting electric energy to heat, so the rating will only effect the time it takes to heat the water, so therefore you cost per hour will be a function of 4 factors (1) Element Rating. (2) Timeperature rise. (3) Water Usage. (4) Heat loss from system.

But if there is no thermostat then the element will just use about whatever it is rated at while it's on

hairy sailor

You can get a plumber to fit a timer,my old man got one a good few years ago,just turn the dial for the required time & it'll switch itself off,google it & it'll give you a idea,

rayh

Daegerty wrote: »

But if there is no thermostat then the element will just use about whatever it is rated at while it's on

Not really - heater element will continue to convert electrical energy to heat energy and if without a temperature control the ultimate water temperature will be the balance between heat energy in (element rating) and heat energy lost through usage and leakage. If this balance is above boiling point, other factors come into play.

Not withstanding this, I dont think that this line is where the original question intended and to answer we would need more information on water usage, levels of heat loss and typical electrical energy costs. Also, heating water on domestic rate electricial energy is not the most sustainable method either costwise or environmentally