Which uses the most electricity?

phlis

Hiya

I have a boiler that is only really used once a day to heat water only. Now I live in rented property and I cannot really make any modifications to the property which includes the boiler. The boiler is not insulated in any way. So my question is this.

Is it more economical to only have the boiler on for like an hour before I actually need the water or is it more economical to keep it on all the time?

Thanks everyone for your help.

Phlis

esuhl

Well... obviously it's going to be cheaper to only turn it on when you need it!!! Think about all the heat loss occurring if you leave it on all the time.

DevCoder

By boiler do you mean hot water cylinder?

If so you could buy an insulating jacket for it and then it would probably be cheaper to keep it on as it wouldn't have to heat the entire tank of cold water each time.

jhs14

It is never cheaper to leave a boiler on all the time, rather than just heating when required.

It can certainly be quicker/more comfortable to leave it on all the time, but it will always use more energy (and thus money).

HTH

Seronera

1) Ensure cylinder is well insulated 2) Turn it on when you need it (or 30 mins before you need it).

The insulation will retain enough heat to ensure that when you do turn it on you use a minimum of energy to get it up to temperature again. Leaving it on all the time is a mugs game. Its been proven time and time again. "Ye canna defy the laws of physics" (Scotty- Chief Engineering Officer...Starship Enterprise)

Ebe_Scrooge

This question comes up time and again - and the answer is always the same, have it timed to come on only when you need it. Yes it's more convenient to have it on all the time ( you'll always have hot water ) but at a cost. The most important thing is to make sure the hot water tank ( and associated pipework ) is insulated to within an inch of its life.

My favourite analogy : Do you leave the kettle on permanently boiling away, just so you can have a cup of tea without having to wait ? Of course not. At the school fete, do they have a tea urn constantly boiling ? Yes, because the speed and convenience of instant hot water is more important than the cost in that scenario.

In a domestic situation, you want to be a kettle rather than a tea urn

StuC75

Have the combination of:

Properly insulated water tank, this will help it retain the heat for longer when outside of the utilised time.

Then have it programmed to be hot for when needed - i.e. bit of time in the morning for showers then evening too..

In fact with effective insulation - less heat would be lost during the day and so may not need as much energy to reheat it later..

think of it as a flask - if you leave the liquid in a cup it will go cold within time (longer to then reheat), but keep the flask closed and it will be hot later - and so wouldn't take as much energy to return it to the boil..

Whilst your alternative would be akin to leaving the stove on all the time just in case need hot water..

JP08

I'm not so sure how much cost difference it actually makes in practice. Surely any heat leaking from your hot water tank is simply keeping the chill of the house at this time of year. Assuming both are heated by the central heating, the cost of the heat from the tank will be offset by the saving from not burning so much gas to heat the house.

Used to make the same argument about incandescent light bulbs - in winter when you are using them more, they simply help to heat the room. Though in this case the heating be electricity from the bulb is a bit dearer than that from the gas central heating.

Also systems in general that are ticking over at a steady state tend to have less wear and tear, expansion and contraction etc. Would not surprise me if a steadily used central heating system lasted longer than one with extremes of on/off usage.

StuC75

Most hot water tanks are in an airing cupboard or loft space - and not a main living space - so would doubt that the tank essentially acting as a radiator for that space is of any benefit whatsoever to anyone, unless they use that space, I know mine never radiated through the brick wall and door to warm up the bathroom..

Assuming the tank has an effective thermostat & range allowed (so not constantly cutting on&off) and the tank is lagged well, then assuming there isn't much usage during the day, then the tank would not need much further heating during the day until later - it would only matter when there was a significant amount of water being used (and so cold water comes into the system)..

JP08 wrote: »

I'm not so sure how much cost difference it actually makes in practice. Surely any heat leaking from your hot water tank is simply keeping the chill of the house at this time of year. Assuming both are heated by the central heating, the cost of the heat from the tank will be offset by the saving from not burning so much gas to heat the house.

Used to make the same argument about incandescent light bulbs - in winter when you are using them more, they simply help to heat the room. Though in this case the heating be electricity from the bulb is a bit dearer than that from the gas central heating.

Also systems in general that are ticking over at a steady state tend to have less wear and tear, expansion and contraction etc. Would not surprise me if a steadily used central heating system lasted longer than one with extremes of on/off usage.

jackyann

If you really only need hot water once a day, then indeed, much cheaper to turn it on to heat up as needed.
Can you time this conveniently? And can you time it to use remaining hot water efficiently?
Eg: have a shower, do washing up, then turn on washing machine?

BUT - see Stu's post - are there other benefits when the tank is hot - and is this an efficient use of energy?
Are you disciplined (or desperate) enough to do this?

You can only answer this by monitoring carefully.

Heedtheadvice

The argument is sometimes made to keep central heating on all the time for efficiency. It is a fallacious argument. Based upon possible condensation on to cold walls needing evaporation to dry them off when the heating is first turned on. It ignores continuous heat loss higher with higher temperatures, ventilation needs especially during the day, etc. Same applies to boiler/cylinder as regards heat loss - keep up to temp when needed only, drying condensation does not apply.

And incidentally electricity is most efficient but very costly compared to mains gas at x3 or x4 the running cost but cheaper to install initially.