The Big Six energy suppliers have launched a campaign to reunite former customers with money left in credit in a move that has been welcomed by consumer groups and the regulator.
The MyEnergyCredit campaign will encourage customers who have switched suppliers or moved home without leaving a forwarding address to get in touch with their old company if they think they have left money behind.
Energy UK said £153 million in unclaimed credit had accumulated over the last six years, with the average balance at around £50.
The trade association said from now on, after two years any unclaimed credit would be put towards funds to help the fuel poor and vulnerable, which would amount to at least £65 million over five years.
Suppliers would "kick start" this new deal with £38 million for 2014 and 2015 combined.
Energy companies will also introduce new standards to minimise unclaimed credit balances building up in future, but "for the avoidance of doubt" any valid credit would always be refunded, however long ago the customer left.
Energy UK's chief executive Angela Knight said: "This is a great campaign launched today and we will be ramping it up throughout the autumn. This money has been left behind and we are urging former customers to come forward and make a claim.
"Customers who think they haven't left a forwarding address or a final meter reading when they moved or switched should contact their old supplier. The web site myenergycredit.com will help you do this.
"Inevitably, there will be some former customers who will not be found and so the major suppliers are announcing what will happen to credit balances from now on. In future, after two years, the credit balance will be used to help vulnerable customers - and suppliers will make it very clear what is happening.
"By 2018, these new arrangements are expected to add up to around £65 million of help to those in difficulties. The suppliers will kick start this process now by donating £38 million for the first two years combined."
Energy minister Amber Rudd said: "People should rightly be returned money that is theirs and was left behind when they moved house or switched.
"Earlier this year, the Government and Ofgem announced plans to get to the bottom of problems with outstanding credit balances and an agreement was reached with the major energy companies to ensure they automatically refund direct debits to customers who are in credit.
"It is very encouraging that Energy UK's new campaign will now work harder to reunite former customers with unclaimed credit balances too."
Ofgem chief executive Dermot Nolan said: "Today's industry announcement is an encouraging first step by the six largest energy companies to address Ofgem's call to reunite customers with their cash.
"It is good news for consumers and if you think you could be owed money we recommend that you contact your previous supplier.
"This issue is part of a wider challenge of delivering good customer service that the industry must crack if they are to rebuild customer trust and confidence. And while Ofgem welcomes the progress made to date, suppliers must now do everything within their powers to return the money and prevent a similar situation from happening again.
"Failure to deliver on the initiatives announced today could trigger further action by Ofgem, including enforcement."
In February, Ofgem told the biggest energy firms to refund former customers more than £400 million held in closed accounts.
The regulator found that the Big Six - British Gas, EDF Energy, E.On, npower, ScottishPower and SSE - were holding at least £202 million from around 3.5 million former household customers between them.
The energy firms had also retained £204 million from 300,000 closed business accounts, Ofgem said, adding that it had found "an unacceptably large" amount of money being retained rather than returned to customers, and a wide variation in company practices.
Which? executive director Richard Lloyd said: "It's unacceptable that energy companies have been sitting on millions of pounds of consumers' cash, so it's good to see moves to ensure people get their money back.
"Ofgem was right to step in to deal with this. To help restore consumer trust in the energy market, suppliers must return this money as soon as possible and be clear about what customers should do when they close their accounts.
"Any money that can't be reunited with the customer should be put towards helping vulnerable people struggling with their bills."
Look through your direct debits and ask yourself whether you are really getting value from all of them. Are you reading your magazine subscriptions? Are you attending clubs? Are you going to the gym? In many cases we have let these roll over in a vague hope that at some point they'll be useful to us again. But unless they're useful to you today, you need to ditch them.
Likewise, look through your cupboards, fridge and freezer and really think about what you buy versus what you eat. Ask yourself whether there are certain things you buy every time you shop that you appear to be stockpiling, or fresh foods that you buy out of habit that end up going mouldy more often than not.
This is particularly vital for car and home insurance. If you automatically renew instead of shopping around, you could be wasting £300 a year or more, so make a note in your diary when your renewal is due, and a week beforehand set aside some time to find the best deal.
The same goes for any service you sign up to. Many will automatically tick the auto-renewal box when you first sign up - so it's worth checking your accounts to see if you have accidentally pledged to buy the same products again next year.
We waste a small fortune by doing things at the last minute, in a hurry, or missing the deadline. Take travel, for example, if you know you are travelling in a few weeks' time you can buy your ticket far more cheaply today. Likewise, if you are ordering a present or something you need for an event, make the time to shop in advance and opt for standard delivery rather than paying for a rush job. And make a point of dealing within anything with a penalty for lateness at least a few days before the deadline expires.
Most of us shop in a state of semi-consciousness, rushing down the aisles and taking things off the shelf out of habit, without really noticing what we're buying. It's no wonder we come home with armfuls of things we don't need.
Shopping needs to be done consciously and purposely. You need to start with a list, and view each item carefully. If you tend to buy a certain brand, have you at least tried the supermarket's own brand to see if you like it as much? If you tend to buy the own-brand, have you tried the 'value' brand? Switching your brain on can save you as much as 30% on your shopping bill
You might be skeptical if someone tried to tell you that your heart starts pounding at the sight of discounted toilet rolls or a BOGOF deal on tins of beans, but actually it does. Your heart rate will increase fractionally and your blood pressure will rise slightly, as your instincts tell you this is a good thing which will help you do your hunting and gathering more effectively and feed your family for less.
In order to avoid making mistakes, we need to think carefully about every deal instead of acting on our instincts. Is this something you were going to buy anyway? Is the discounted version cheaper than the one you normally buy? Is it a multibuy that's going to last long enough for you to use it? It's always worth bearing in mind that it's only a good deal if you were actually going to buy the product at full price anyway.
Even the most organised people tend to think about supermarket shopping once a week - just before they go. They might think about their likely meals, look at what they have in the fridge, and make a list of the additional things they need. This is all very well, but assuming you do this on Saturdays, you also need to make a date to check the fridge on Wednesday too.
On Wednesday there's still a chance to prioritise those things which are going out of date, or freeze the things you're not going to get to. By Saturday they will have turned to mush in the vegetable drawer.
This is something we've all heard from organisations trying to persuade us to go green, and somewhere in the back of our minds we know we're being wasteful. It can be easy to get into the habit of turning things off by remote control and leaving the red light flashing. However, when you hear that this little habit costs the average household £80 a year, it begs the question as to whether it's really so hard to turn it off properly.
We sometimes forget we live in a free market economy, and instead we stick with the companies and services we have always used. In some cases this is a very sensible idea - because we know we are going to a trusted hairdresser who always does a good job, or a dentist who is very reliable.
However, sometimes we find ourselves sticking with a company just because we have been a customer for so long - even if they have let us down in the past.
There's no logical reason for this loyalty, and it's often costing us money. So divorce the things we stick with for good reasons from the things we think we're stuck with, and vote with your feet.
There are some things we do because they are convenient, which we get a lot out of. If there's one night a week when you don't get home until 8pm and you're too tired to cook, it would be daft not to have something easy in the house to throw in a pan or the oven. No-one is suggesting you should sacrifice the conveniences you rely on to make your life work.
However, there are all sorts of 'conveniences' you may have fallen into because you think they make a far bigger difference to your life than they do. Try an experiment. If you usually buy cheese slices or grated cheese, bags of salad, carrot in sticks or sliced 'stir fry' ingredients in a bag, try buying them in a more traditional format for one week. If chopping, slicing or grating sends you over the edge, by all means go back to what you were buying before. If not, you could end up saving £100 a year.
All of us have an area in life where we know we could be less wasteful if only we understood a bit more about it. If you want to make cheaper overseas calls, stream movies for less, make calls for free, or track down a cheaper holiday, there are clever ways of doing it all. In an ideal world we could all become experts at it all. In the real world your circle of friends and acquaintances is going to be home to someone who's an expert in each field. What's even better is these experts will enjoy sharing the benefit of their knowledge, so make them a cup of tea and let them solve your problems