What does it REALLY cost to run your energy guzzling household appliances? (Less than you think)

jobbingmusician

Rosa_Damascena said:

I have concluded that the real cost is so detached from ever-rising bills and the realistic prospect of paying them, it's not worth the brain-space to do the calculations, just switch off what you can and huddle under a blanket when the daylight fades to night.

All very well, but we are talking about people really on the breadline here.  They need to know whether using their slow cooker costs 4p or 40p, and they need some good proof that the oven DOESN'T cost £7 an hour.  (Obviously I can do the latter, but I'd like data to tell them what it actually DOES cost.)

jobbingmusician

bouicca21 said:

My basic arithmetic having long since atrophied, I have taken a much easier path to calculate costs.  I have started reading the meter just before I put an appliance on, and again when said appliance is switched off.  Obviously there will be things working away in the background but I figure that finding the actual increase in consumption is a reasonable if rough guide to what an appliance costs to run and it saves all those complicated sums (plus the faff of trying to find out what each appliance is rated at).

I have only just started doing this.  Initial results: (I’ve got a fairly standard sized cooker with two ovens).  Running the bigger of the two ovens for an hour at 170 degrees used 1.3 extra units.  Running the smaller oven at 150 degrees for 35 minutes used 1 extra unit.

Tomorrow, the slow cooker!

This is useful. You don't say what the units are, though.  Are these Kw?  That would be about what I would expect.  Modern ovens use hardly any power once they have heated up, so the fact that your two ovens used broadly similar amounts of electricity is plausible.  The smaller oven *should* have had a reading very little higher (still about 1 unit) if you'd left it on for the extra 25 mins.  The cost of 1.3 kWh would be around 38p, which would be in the region I'd expect.

jobbingmusician

Tardis4 said:

Another thing to consider, which complicates it further. Most SC cookbooks say to brown any meat first, and also to use boiling water for the stock. So you are preheating what goes into the SC if you follow those recipes, and will have already used some electricity. However, some people throw everything in as is then just cook it for longer, much longer i.e. overnight and seem to get the same results. 

I totally agree.  And it will obviously reduce SC costs if the ingredients are hot, and reduce costs even more if the crockpot itself is hot.  Most of the energy the SC uses is actually in heating up that big stoneware pot.  Once the pot is nice and hot, you could in fact turn the whole thing off and transfer the pot, with its contents, to a hay box. (But by this time, when the pot is hot, you are using minimal electricity since the thermostat will ensure that the heater only comes on very infrequently to maintain the temperature).  Anyway, the cheapest way to cook your SC contents is likely to be to just throw everything in cold.  I tend to do this often just out of laziness, and you can still produce a tasty casserole after 6 hours.

jobbingmusician

otb666 said:

Surely if the cooker is jammed packed it will work harder than with one or items in it. Also if you then freeze surplus more electric used  Basic physics or Maths I dunno which.  The same thing with boiling kettle and using a flask. You are still boiling same amount.  So at end of day I just use what i need when i need it. Rather than all this over boiling and cooking  for the future.

This is actually more complicated than it at first appears.  It is clearly economic to batch cook - if you fill an oven with stuff and cook it, and then immediately use the hot oven for more stuff once the first lot is out, you are starting with a hot oven.  Your comment about a packed cooker working harder.... well yes, I appreciate that it takes more energy to get a larger volume of stuff up to temperature.  But then when it reaches temperature, the stuff itself becomes a hot thing which helps the oven to maintain its temperature. (The converse of this is why you don't run a big freezer with one thing in it.  You fill it up so that things help to keep other things cold.)  I suspect the detailed maths behind this is quite complex, but that's the simple theory.

I doubt that any of the very poor people who are scared to use an oven or even slow cooker are freezing their cooking, so the comment about freezing surplus is probably irrelevant though true.  In the Utopia in my head, people deal with their surplus by giving it to neighbours that night, and receive their next day's meal from those same neighbours.....

A quick comment to all those who are opposing the flask idea.  You should NOT boil only the water you need in an electric kettle.  There should always be some spare water so that the element doesn't boil dry - if you totally empty a hot kettle, the element is liable to die on you quite quickly.  So it is in fact economic to save some hot water in a flask.

TheAble

Boiling a litre of water in a 3kw kettle takes around 2 minutes in my experience. So that's 1p. Browning some meat, which will make for a tastier dish - another 1p, say? Minus the cost of the elec that the SC would otherwise use to heat said meat/water. Might be a bit in it but not much.

The standing charge also has to be borne in mind. Granted it's a sunk cost but if you are going to shell out 29p a day on this it doesn't make sense to me to then turn everything off and eat cold food/get the flask out (a popular topic!) for the sake of an extra couple of pence.

Effician

TheAble said:

Boiling a litre of water in a 3kw kettle takes around 2 minutes in my experience. So that's 1p. Browning some meat, which will make for a tastier dish - another 1p,

Boiling 1l of water will uses approx 0.2kWh of electric ( water at 10c to 100c) , at the new cap rate that would be about 5.5p.

Would certainly work out cheaper using stove kettle on gas hob.

More difficult to quantify the meat browning as so many variables.

maisie_cat

I did quite a few tests a few weeks ago, but cannot find my notes.
What I did take away from it was that cooking in a slow cooker 6 hrs, pressure cooker 15 mins then keep warm or using a breadmaker 3.5hrs costs around the same, 11p on my old tariff and 15p now.
That's means cooking a huge vat of something hot should not be unaffordable.
We cook lots of 1 pot meals so not much need for carbs or sides cooked separately. I reckon we use 1.5 Kwh/day average cooking including drinks, so 50p all in, the same as a tumble load. Our daily average is 7.6kwh/day or £2.50 compared to council tax £6.20 a day.

Tardis4

If we're talking about really saving money, then someone on E7 could throw everything in cold last thing before bed and cook on low overnight. Our E7 doesn't kick in until ridiculous hours though, plus you have to put up with the cooking smell all night in a tiny space like ours.

thriftwizard

@Rosa_Damascena, looking at our account online, our actual usage was about £150 plus VAT. But the bill was considerably more; our DDs more than doubled from £160 when our fix ended at the end of January. We seem to have quite a bit of credit on the account just now, which DD1's partner, an energy consultant, says is "front-loading" for next winter, anticipating the autumn price rise. However the incoming double-glazing should make quite a difference, so he's advised me to go over to a monthly variable DD, just paying for what we've actually used, so they don't have the use of our money for the best part of a year.

jobbingmusician

Effician said:

TheAble said:

Boiling a litre of water in a 3kw kettle takes around 2 minutes in my experience. So that's 1p. Browning some meat, which will make for a tastier dish - another 1p,

Boiling 1l of water will uses approx 0.2kWh of electric ( water at 10c to 100c) , at the new cap rate that would be about 5.5p.

Would certainly work out cheaper using stove kettle on gas hob.

More difficult to quantify the meat browning as so many variables.

How do you work this out?  

I agree that boiling water in a kettle takes about 2 min.  A kettle will not draw more than 3kW, and I think we can agree that the kettle is likely to be working flat out for these 2 minutes, actually drawing 3 kW. So this is 1/30th of an hour multiplied by 3Kw - a tenth of a kWh.  Which is about 3p  (2.9p at 29p a kWh), not 5.5p or 1p.    

Let me know if I am wrong, and folks, please show your workings so that we know how you are coming up with the figures you are quoting.  Most of the websites and information out there which are misleading people contain statements without showing how the figures are arrived at.  I know we are talking pennies in this precise instance, but we are also talking about people who don't have these pennies.