Do these electric calculations look correct.

[ss]

Does this figure look correc,t using a 7.5KW shower 10 minutes a day costs only £2.43 per quarter, appears to be too cheap a running cost.

Watts 750 Watts/1000 0.75 hours used 5 kw x hours 3.75 unit price 22.29p kwh pence 2.6748 divide 100 £0.03 cost week £0.19 cost 91 days £2.43

[Bill Taylor]

Looks wrong to me, although I don't understand your calc.

10 minutes per day is 15.2 hours over 91 days.

Multiply by 7.5 gives 114 units.

Multiply by 22.29p gives £25.35.

Those are very expensive units!

[Phil]

s only ?2.43 per quarter, appears to be too cheap a running cost. W atts 750 Watts/1000 0.75 hours used 5 kw x hours 3.75 unit price 22.29p kwh pence 2.6748 divide 100 ?0.03 cost week ?0.19 cost 91 days ?2.43

7.5kW is 7500W (ie. watts/1000 = 7.5)

[ss]

Thanks guys I used 750 instead of 7500. The unit price is the high rate which drops to 13.73 and averages 15p overall. I put the high rate in my spreadsheet and it calculates at an average for me.

Thanks

[dom]

Mistake on the first line. Should be 7500W.

[The Natural Philosopher]

Try 7500

[John Williamson]

Well, the power consumed is out by a factor of 10, for a start. It's

7500 watts, plus or minus the tolerances. So £24.30 or so is the right answer.

[Roger Mills]

It sounds as if you're on a tariff with no standing charge - where you pay more for the first so many units per quarter, and a lower rate for the rest.

Unless you're ever in the situation where you don't use all of your dear units, it may be better to calculate the *effective* standing charge[1] and write that off. You can then calculate the *marginal* cost of using any given appliance, based on the price of the cheaper units.

[1] (high unit price - low unit price) x Quarterly No. of dear units

[Dave Liquorice]

Is that E7 or one of those stupid "no standing charge" tarrifs where you pay the standing charge by a higher rate for the first n units/quarter?

Either way those still strike me as high prices:

E7 here is 16.08 p/unit day 6.08 p/unit night, 18p/day standing charge (EDF Blue Price Promise Feb 15).

Ordinary "normal use" is 11.143 p/unit, 20.95p/day standing charge (iSupplyEnergy iFix201405)

Ordinary "low use" 15.06p/unit 10p/day standing charge (Npower Go Save).

Norweb area plus VAT @ 5%.

[Brian Gaff]

Have you not dropped a 0 off your wattage?

Brian

[A.Lee]

That looks a hard way of calculating electric costs.

7.5kW x 5 hours = 37.5 units. 37.5 units x 22.3pence = £8.36 for 5 hours of use.

Thats basic, the shower is unlikely to use 7500w, but it gets you into a rough idea of cost.

[ss]

Got it sorted now (dropped a zero) Thanks for the input.

[harryagain]

It goes likw this, A unit is a Kwh.

7.5 Kw x 10/60 = 1,25Kwh per day If Kwh price is 0.223 Cost per day = 1.25 x 0.223 = 0.28/day Cost /week 7 x 0.28= 1.95 Cost/91 days=91 x 0.28=5.32

[ss]

Yes thats correct, I have done the sums and I am better off with this tariff as I shut the house down for 8 weeks in the year for hols.

[Bob Minchin]

+£20

[Roger Mills]

and a bit more

According to my calculator, 91 x 0.28 = 25.48!

[Jim K]

f*ck me is that how you costed up the bat(tery)-mobile?

Jim K

[harryagain]

Ah yes. Must have had a senior moment.