A price comparison website says energy firms are battling to offer the cheapest deal on the market but there is not much between them.
According to uSwitch, Extra Energy's fixed price deal to November 2015 was currently the lowest on offer at an annual average of £976 under its calculation formula - with just £1 separating it from the next cheapest, First Utility's iSave.
Its energy spokesman, Tom Lyon, said: "With temperatures starting to fall, competition is really starting to heat up in the market.
"Extra Energy undercut First Utility's latest tariff by just a pound only a few hours after it was launched, bringing them back to pole position in the best buy tables.
"But the 'Big Six' are now raising their game and responding with more competitive deals.
"npower's new tariff at £1,000 is fixed to November next year ... meaning that 'Big Six' suppliers now offer five of the ten best deals.
"As winter approaches, there's no sign of this price battle ending and consumers look set to be the winners."
uSwitch released its report as suppliers remain under pressure over prices - with the industry regulator Ofgem keen that falls in wholesale costs are passed on to customers.
It wrote to firms in June citing a 38% annual fall in wholesale gas for next-day delivery.
Costs have fallen further since amid lower oil prices and weaker demand.
The 'Big Six' Firms, which have denied suggestions they are quick to put prices up when costs rise and slow to cut them, have argued they face growing costs to maintain and expand energy provision and pricing depends on when the wholesale energy was bought.
They also point to lower profit expectations.
There are fears of an energy crisis this winter after fires at npower's Didcot gas-fired power station earlier this month and at Ironbridge and Ferrybridge.
As cracking problems continue to be checked at Heysham and Hartlepool nuclear power stations, some 4.3 gigawatts of the UK's conventional and nuclear electricity output has been taken offline.
It amounts to 7% of the total.
There is also more energy capacity temporarily offline due to planned maintenance or statutory outages.
Meanwhile, grid operator National Grid has announced measures to keep the lights on, including a scheme which pays businesses to reduce electricity use, and ministers have insisted the lights will not go out.
