Billed as a "three-day switch", the move also includes a standard 14-day cooling-off period before the clock starts ticking on the switching process.
And industry-watchers think the change could put new pressure on suppliers to keep a lid on prices.
Mark Todd of independent price comparison website EnergyHelpline.com said: "The more people switch, the more pressure there will be on suppliers to charge competitive rates. Currently, an average UK home only switches energy [provider] once every eight years. If competition is to work well, this rate needs to double."
Meanwhile, the UK's "Big Six" energy companies are receiving a record number of complaints, consumer group Which? said last week after examining figures from the suppliers. Customers made 1.7 million complaints in the first quarter of 2014, up from 1.48 million in the same period last year.
Npower was the worst offender, with 83 complaints for every 1000 customers, up from 49 per 1000 at the same time last year. It took over bottom place from EDF, which had 46 complaints per 1000 customers, down from 77 per 1000 last year.
SSE's tally doubled from 13 complaints per 1000 customers to 27, on a par with E.On and British Gas. ScottishPower received the fewest complaints, at 13 per 1000 customers.
Which? executive director Richard Lloyd said: "Yet again, millions of customers are being let down by poor service from the Big Six energy companies."
Industry body Energy UK, said: "In an industry which serves 27 million households, sometimes things can go wrong. Most issues just take just a call to fix, even though all problems - large and small - are lumped together."
Meanwhile, Todd said his research shows wholesale energy prices have dropped dramatically since last autumn, when the most recent round of price rises kicked in. He said: "Wholesale gas prices are down 12% and electricity is down 17%. By our calculations, suppliers could therefore pass through a price reduction of £77, 6%, to a typical household bill … from £1,315 to £1,238 a year."
But will it happen? According to Francis, energy companies claim they are not seeing their profits rise as a result of the price falls because wholesale costs are only one factor in the mix affecting end prices.
However, she added: "But they do account for nearly 50% of our bills, which is significant. If wholesale prices had been moving in the opposite direction, I think we'd be bracing ourselves for higher bills. There is little wonder there is so little trust in the energy market."
MoneySupermarket.com commented: "There is choice out there and the likes of smaller providers such as First Utility, Extra Energy and OVO Energy are offering cheaper deals which could knock around £127 off the average household's annual energy bill."
Meanwhile, four households out of 10 in Scotland are concerned their energy bills are not accurate, according to new research. A hefty 44% are worried they are paying for more energy than they consume, while 39% do not know what they currently pay and 38% do not understand their energy bill.
The research by Populus for Smart Meter GB, the body overseeing the roll-out of smart meters to every home over the next six years, also found more than half of Scots bill-payers (53%) did not trust any energy supplier.
Some 45% of consumers have expressed an interest in having a smart meter installed. The roll-out involves all the electricity and gas suppliers and networks.
Sacha Deshmukh, chief executive of Smart Meter GB, said: "In an era when we are able to compare, record and track our household spending more easily than ever before, two in five of us have no idea whether we're paying too much for our energy. That is why it is so important that government is driving forward the programme rolling out smart meters."