Consumers are being urged not to lock into fixed energy bills, but instead wait until January when prices for gas and electricity are expected to come down.

Capped tariffs offer protection from rising prices by setting the rate you pay over a specified time, and so are cost-effective if you can sign up before prices rise.

In the past year, household energy bills have risen by a staggering 42 per cent, meaning those who took out a fixed plan at the start of 2008 will have avoided some of the extra costs.

The cheapest fixed plan on offer now is EDF Energy Price Freeze 2009, costing £1,169 for the average home. But experts are predicting that tariffs for gas and electricity could drop by as much as 20 per cent in the new year, and warn that those who fix a price now will miss out on the decrease.

Jo Ganly at uSwitch.com, also points out that although capped rates offer security, some charge exit penalties for customers who switch out of them before the fixed time period is up. EDF Energy charges an early termination fee of £20 for electricity and £30 for gas.

Instead, consumers are being advised to shop around for the best rates on offer.

This week, EDF Energy reduced its online plan for customers by 7 per cent.

Confused.com says it hopes the move will spark a price war in the energy market, although, as yet, other suppliers have remained vague over their plans to lower prices.

The rate at which energy bills have risen over 2008 has made them into an increasingly important political topic.

Suppliers have blamed the rise in wholesale prices, but consumer prices have remained high in spite of recent falls in wholesale gas and electricity prices as a result of falling oil prices.

Now, the government has waded in to demand that suppliers lower gas and electricity charges for consumers or risk increased regulation.

Last week, Ed Miliband, the energy secretary, said the government was prepared to legislate against gas and electricity companies if they did not make cuts to household energy bills.

The companies claim that because they buy gas and electricity on forward markets, changes to wholesale prices are not immediately seen in retail prices. But they have started to reduce rates.

Following a report by regulator Ofgem into fair pricing, Centrica and Scottish and Southern Energy reduced their prices for customers with pre-payment meters, who often have poor credit scores and are unable to get billed meters.

Consumer sites have cautioned that even if prices do fall, household bills will still be considerably higher than they were a year ago. They say customers should be more alert than ever to possible ways of cutting energy bills.

As well as reducing consumption of energy and checking estimated bills, up to 20 per cent can be saved on your bill by switching energy supplier, according to Martin Lewis at moneysavingexpert.com.

Comparison sites on the internet such as moneysupermarket.com, uSwitch, Moneyexpert and the FT’s Compare and Apply online tool allow customers to compare prices for tariffs, although not all sites list all suppliers.

Some, such as uswitch and energyhelpline.com, also provide cashback of between £15 and £60 to customers who switch. For example, by going through consumer site Moneysavingexpert.com to energyhelpline.com, customers can earn £15. However, bigger savings can be made by using cashback sites such as quidco.com, which offers £60 to those who switch both gas and electricity.

Before signing up to the deal at the top of best-buy tables, consumers should also consider using one supplier to provide both their gas and electricity, which can save money. EDF Energy offers a standard monthly duel fuel plan, costing £1,211 for the average home. If customers agree to receive bills by e-mail rather than through the post there are further savings to be made. Online tariffs, such as the npower Sign Online Dual Fuel tariff at £1,063, are about 10 per cent cheaper than standard rates.

But before signing any new deal, experts recommend talking to your existing supplier to see if it will match competitors’ rates and offer any other incentives.