I did the sums on the back of an envelope first and on the spreadsheet second, and they disagreed by £4, which for a woman who used to balance a branch till to the penny is a personal affront. It turned out I had counted 31 days in June. By Friday evening, with the in-home display on the windowsill showing 0.09 kW and the house finally quiet, I had the right answer. We fixed our energy on 1 November. It is now 26 June, which seemed a fair moment to ask whether that was the right call.
What I compared
The fix is 24.6p a unit for electricity with a standing charge of 49p a day, and 6.1p a unit for gas with 29p a day. Against that, I priced the same readings at the variable rates our supplier published for each period, which moved in January and again in April, a little lower on the second occasion. The period is 1 November to 25 June, which is 237 days, and in it we used about 9,200 kWh of gas and about 2,100 kWh of electricity. I'm using the smart meter's own figures, not estimates: on the last day of every month I stand in the kitchen and photograph the in-home display, and the eight photos live in a folder next to a spreadsheet tab called Fix.
- On the fix: about £1,258
- On the variable price: about £1,316
- Difference: about £58
So by my rough sums we're £58 better off than the variable price would have left us. That's about £7 a month, or 24p a day. It is not a lot, and I'm aware that I'm measuring against a price I never paid, using rates I read off a page. If the variable rate had fallen sharply last winter I'd have lost, and I knew that in October. A fix cuts both ways.
My first pass was a lot rosier. I priced the whole period at last spring's variable rates and got a gap of £154, which felt too good to be true, and was. Those weren't the rates we'd have been on. So I threw that sum away and priced each month at the rate that applied that month. The honest figure is the smaller one.
What it taught me about our usage
The thing I hadn't felt in my stomach until I added up the months is how lopsided our year is. January used 1,850 kWh of gas and 312 of electricity. Priced on the fix, that one month came to about £214 of energy, against a direct debit of £142. June is running at about £87. The direct debit has been a bit less than we use in the winter and a good deal more in the summer, and the account has moved up and down like a see-saw. As of Tuesday it stands £68.40 in credit.
The standing charges are the bit I can't touch. At 78p a day, they come to £284.70 a year, whether we're home, or in a cottage near Hawes, or out all day on the moor. That's roughly a sixth of what we spend, and it doesn't care how many loads of washing I put through. I've decided not to be cross about it. It's a line on a bill, and I've drawn a box round it on the sheet.
The other thing I noticed is how much of the winter was gas. The thermostat stayed on 19, the radiators were bled and the front door had its draught strip, and still January's gas was six times the electricity by units. In pounds it was only about a third more, £122 against £92, because a unit of electricity costs four times a unit of gas. That surprised me.
So, the right call?
Narrowly, yes. The £58 is a comfort, but the bigger thing is that the direct debit has sat at £142 since November and there hasn't been a letter. In April, when everything else on the sheet moved, this line didn't. I like a line that doesn't move. I'd make the same decision again, with the same shrug.
It's one family's one winter, and I don't think it tells anyone else anything. The fix runs to 31 October.
The sums: £1,258 on the fix and £1,316 on the variable rates, a £58 gap over 237 days, or 24p a day.
