The heating went on for the first time on Sunday 12 October. By Monday evening the in-home display on the kitchen windowsill had turned from green to amber and stayed there, which is the colour it goes when it thinks you're being silly. That was the push I needed. We've been on the variable price since 2021, and I'd been telling myself for about four years that I'd compare tariffs "when it settles down". It never did, so on Monday night I sat at the kitchen table with the laptop, the bills sheet and a mug of tea, and did it properly.
Start with our own numbers
I didn't look at a single price until I'd written down what we actually use. The smart meter, which has been in since February 2024, gives a total for the last twelve months, and mine said roughly 2,980 kWh of electricity and 11,400 kWh of gas. Those two figures are the only ones that matter, because every comparison page I've ever seen leads with a typical household, and we are a particular household with a combi boiler, a heated airer and one dehumidifier.
We were paying £163 a month by direct debit, which is the number on the bills sheet. The unit rates on our latest bill were roughly 27p a unit for electricity with a 54p daily standing charge, and 7p a unit for gas with a 33p standing charge.
Reading the tariffs
The thing I'd forgotten from my years in a building society is that the headline rate is rarely the whole story. Two of the fixes I looked at had lower electricity unit rates than the one we chose, but higher daily standing charges. Multiply that standing charge by 365 and the "cheaper" tariff turned out to be about £20 a year dearer for our usage. The other thing to check, boringly, is whether there's a fee for leaving early. Ours doesn't have one, though I read that bit twice.
So here are the two annual sums, using our own usage:
- Staying variable: electricity £804.60 plus £197.10 standing charge, gas £798.00 plus £120.45 standing charge, £1,920.15 in total
- The 12-month fix we chose: electricity at 24.6p, £733.08 plus £178.85 standing charge, gas at 6.1p, £695.40 plus £105.85 standing charge, £1,713.18 in total
The gap is £206.97 on paper. The supplier's suggested direct debit on the fix is £142 a month, which is exactly £1,713 divided by twelve with a little rounding, so I trust it. We'd be paying £21 a month less than now, and the credit builds in summer and gets spent in January, the way it always does.
Why we fixed
I want to be careful here. "On paper" is doing a lot of work in that sum. It assumes our usage stays the same and it assumes the variable price stays where it is. It might not, in either direction. If the variable price drops, we'll have paid more than we needed to, and I'll notice and say so here. I'm not predicting anything. I'm describing what we chose.
The reasons were duller than the numbers. One is that I wanted the energy line on the bills sheet to be the same figure in March as in November. A year of not thinking about it has a value I can't put a number on, but it exists. The second is that Rob and I agreed, in about four minutes and with only one raised eyebrow, that if we're going to heat the house to 19 degrees all winter, we'd rather know the price. And the third is that we are not in a position to absorb a surprise in January, which is the month our gas use peaks and the month my work phone doesn't stop ringing.
So on Monday 13 October I chose a 12-month fix starting on 1 November, which runs to 31 October next year. I made a copy of the confirmation and the terms and put them in the folder in the bottom drawer, along with the insurance schedule and the boiler service sheet. The folder is getting fat and I find it satisfying.
There's already a reminder in my phone for 1 September next year, to start looking again. The fix ends on 31 October 2026, and I've told myself I won't leave it until the heating's on this time.
