Some of those struggling to pay have been forced on to more expensive prepayment meters, prompting energy regulator Ofgemto strengthen rules to protect consumers.
The government launched its Energy Price Guarantee in October 2022. It replaced the previousOfgem energy price cap, and limited a typical dual-fuel household's annual energy bill to Â£2,500.
This remained in place until the end of June 2023, when the Ofgem cap was reinstated, at which pointa typical annual energy bill fell to Â£2,074.
Under the previous price cap,typical annual bills fell to around Â£1,923 between October and December.
The energy regulator has since changed its estimates of the typical amount of gas and electricity used by households, and recalculated the cap to Â£1,834.
That willrise by 5% to Â£1,928 in January.
If you don't agree a payment plan with your supplier, they might try to force you to have prepayment meter installed, or they mayswitch an existing smart meter to prepayment mode.
In very rare cases, if you haven't paid a bill after 28 days, you might be threatened with disconnection, but you'll normally be offered a meter first.
If you've reached state pension age, your supplier can't disconnect you between 1 October and 31 March if you either:
Suppliers can pass your details to a debt collection agency - and you might be charged more to cover the cost of this.
Many suppliers also charge extra fees for late payments.
Paying by direct debit is normally the cheapest way to pay for electricity and gas. Cancelling a direct debit means future bills are likely to be higher.
Non-payment could also damage your credit rating, and make it harder to borrow money.
The regulator Ofgem reviewed the use of prepayment meters after aninvestigation by The Timesfound debt agents acting for British Gaswrongly broke into vulnerable people's homes to fit meters.
Energy suppliers were subsequently banned from forcing a pre-payment meter on a customer while Ofgem investigated. The regulator has now said companies may resume the practice but must first get its permission and a court warrant.
Ofgem believes suppliers should be allowed to retrieve their debts. However, undernew rules, suppliers must give customers more opportunity to clear their debts, contacting them at least 10 times before installing a meter. They also have to conduct a "site welfare visit". Ofgem says no company has yet passed its new stricter tests.
The rules state meters cannot be fitted for:
Those forced onto a prepayment meter will get Â£30 initial credit to reduce the risk of them losing supply.
The government has said prepayment energy chargeswill be cut, bringing them in line with direct debit rates.
Suppliers have also been told to identify households where meters were wrongfully installed, return the customer to their previous tariff and offer compensation.
Check your direct debit
Your monthly payment is based on your estimated energy use for the year, andyour supplier may reduce your bill if its estimate is higher than the amount you actually use.
You can also request a flexible monthly direct debit where you only pay for your actual consumption. This requires a smart meter or regular readings.
However, two-thirds of gas usage is during the winter months, so make sure you understand the impact of reducing payments during warmer weather.
Pay what you can
If the direct debit is fair, but you can't meet it, ask your supplier for an "able to pay plan" based on what you can afford.
By paying something every month - even if it's less than the amount due - your arrears grow more slowly, and your supplier may be less worried about your debt.
You may be able to get your name added tothe Priority Services Register (PSR), a list of households entitled to extra support.
Those eligible include pensioners, pregnant women, parents of young children, and people who are disabled.
Ofgem also recommends asking your supplier to add your name to the Network Operator Register, if you rely on your energy supply for medical reasons.
If you have different gas and electricity suppliers, you need to contact them both.
Being on the PSR doesn't cancel your arrears. But it does show that you are vulnerable, which your supplier should take into account.
Claim any relevant benefits
Theindependent MoneyHelper websitehas a useful guide to available benefits, whilePolicy in Practiceand the charitiesEntitledtoandTurn2usrun benefits calculators.
You may also be able to repay your debt directly from your benefits through the government'sFuel Direct scheme.
A number of suppliers and charitiesalso offer hardship grants.
Check you're getting extra government help
There isa range of government support to help with energy bills, available to households on means-tested benefits, pensioners and people on certain disability benefits.
The next payments for some eligible groups should have been made between 31 October and 19 November.
Adjust your boiler
If you have a combi boiler at home - you don't have a hot water cylinder and there is a (usually white) plastic pipe under the boiler - you may wish to consider turning down the heating flow temperature.
On the front - sometimes behind a flap - look for a dial or set of buttons with a radiator icon. Turn the dial to the number three, or the 12 o'clock position. If it has a digital display, select 60C.
You may also want to turn off the hot water pre-heat. Many boilers come on every few hours - night and day - to ensure there's always some hot water available.
Most homes don't need this, and turning it off saves money.
Annual energy bills will rise in January when households look to keep warm during the coldest time of year.