Switch energy before the shock bills

With winter energy usage double that of summer, now is the time to switch to a cheaper tariff.

Small energy supplier Ovo Energy, almost a cult to many of its existing customers, put up prices for new customers on its fixed tariffs by a mere 6% from 26 October, the last of the suppliers of note to raise prices this year.

And just days later, the clocks have gone back. An extra hour's sleep is our compensation for the cold and dark to come, but it's also a reminder to switch energy, and switching as we start to use our heating and lighting more is not a bad time to do so.

Switch now, not after price rises are announced

As time goes by, the supplier gradually – or sometimes not so gradually – starts increasing prices for existing customers, but newer customers on online tariffs might get a period of stability first.

It's hard to see the full picture, but the evidence I have managed to gather so far indicates that at least a few suppliers – although perhaps not all of them, and certainly not all of them all of the time – try not to anger the newest online customers by putting up prices for customers on the newest tariffs, even if they have otherwise just announced a general price increase.

If you compare tariffs online, you generally can only buy the newest tariffs, since they tend to be replaced every few weeks or months. This means that with a bit of luck your tariff shouldn't be increased before at least half the winter has been and gone. Since we use around twice as much energy in the colder months than in the warmer ones, this should lead to considerable savings at just the right time.

Switching in autumn or early winter is probably a better idea than the strategy of waiting for the big six suppliers to all announce price changes, and then switch. I've explained why the second strategy doesn't work in the 2009 article Recent energy-price reductions were a sham, demonstrating that those following the standard guidance to wait actually lost money. In the two years since then, I've seen the same thing happen again, whether suppliers are raising or lowering prices.

Whether to fix

Fixes might not be the best idea at this time unless there's one in your area close to the top price. At present, there are a few tariffs that might qualify where you are, including EDF Fix for 2012 or ScottishPower Online Fixed Price Energy January 2013.

If you're worried suppliers might actually announce price reductions after you fix, you probably shouldn't be. The cheapest variable tariffs often don't fall with major announcements, or so my burgeoning collection of spreadsheets from the past three years seems to indicate. Therefore, assuming you don't want to switch for another year or so, you might not lose out by fixing on one of the cheaper tariffs even if prices for those on standard (aka expensive) tariffs come down within a year.

Choosing a variable tariff is not just about price

The cheapest (i.e. the newest) variable tariffs are, on average, hundreds of pounds less expensive than standard tariffs, and you can also expect them to be considerably cheaper than variable ones that have been around for a few years, which get nudged and yanked upwards in price.

When switching to a new variable tariff now, pay attention to annual discounts, particularly if you switch more than once per year.

Annual discounts are included in the savings results of all online energy comparison tools. They do this for consistency, which is desirable, but how they have chosen to do it causes problems; for example, most suppliers don't pro-rata annual discounts. Instead, they pay them once you reach the anniversary only. Unless you switch just after the 12-month anniversary, you will lose the entire discount, which could be £50 to £200, and that might wipe out all or most of the benefit of switching away from standard tariffs.

Some discounts are guaranteed to stay widely lower than the supplier's much more expensive standard tariffs for a year or more. ScottishPower's Online Energy Saver 16 is an example, which promises for many users at least 12% lower prices than its standard tariffs for more than a year. This prevents the supplier pushing up your prices much faster than standard tariffs during the period.

Another point is exit charges. These are usually charged if you leave within 13 months or even longer periods. However, if you leave because you're moving home, the charge is often waived. Regulator OFGEM also made it clear to me recently that you should tell the supplier to waive the exit charge if you are leaving an ordinary variable tariff because the supplier has just raised the price, but you have to switch quickly after the announcement in those cases.

Keep track of what you're doing

For around 30 minutes work a year, you could save dozens or hundreds of pounds. That's better than doing an hour's work for most of us. But your effort doesn't just involve switching, but a tiny bit of admin too.

In addition to the 5-20 minutes it might take you to compare and switch, you should put the end date of your new energy deal in your calendar, because after that point you might receive another particularly big jump in your tariff price – on top of whatever other increases might have occurred in the year. Suppliers have ways to bury increases in your contract that allow them to increase the price without warning you too, so it may not hit you that you're being ripped off until the next bill arrives.

You should also note in your calendar the anniversary dates of large discounts, as well dates when you can leave without paying an exit penalty. Anyone who wants to be good with money should have a financial calendar. Plenty of online calendars from major websites like MSN and google have calendars that allow you to set email reminders of events.

More: lovemoney.com's gas and electricity tool clearly explains the discounts in the results page of your search. Just click on the tariff name for more details.