Martin Lewis urged households to check if their energy credit for bills as some may be due a refund worth hundreds.
In the recent Money Saving Expert (MSE) newsletter, Martin said it was the "perfect time" to check the level of energy credit on your energy account if you pay by direct debit.
Around 65% of us pay our energy bills by direct debit and energy companies are believed to be sitting on around £7billion of cash which is sat purely in credit.
The beginning of May is the "spot-on perfect" time to check as early May is the baseline for when you should have minimum credit in your account - so if you have too much then could get some back.
However, Martin explains that it isn't as simple as "if you're in credit, you're owed cash".
With direct debits, your energy supplier will take your annual costs and divide them by 12 - this smooths it out so you are not paying madly high costs during the winter months.
According to the Money Saving Expert, you should have "peak credit" in November and this will obviously depend on how much your direct debit is and how much your energy usage is.
So if you have cut back a lot and your monthly direct debit amount is too high - your credit pot will get bigger.
So if you have a lot of energy credit in May, how you can get some of its back depends on your supplier.
Only one UK supplier currently promises automatic refunds if your credit is too high on the anniversary of you joining - this is Scottish Power.
The rest, however, require you to check.
With British Gas, if you're in credit at the end of your "plan year" it will reduce your direct debit but it will not offer you a refund - you have to ask for one.
This is a similar approach to EDF, however, you will be automatically refunded £150 if you're energy credit is above this.
with E.on Next, Ovo Energy, SSE and Octopus you have to request a refund.
It should be noted that energy firms will not just give you cash back if you ask - you will have to follow steps such as supplying a recent meter reading.
You are advised to check that your meter readings are up to date before you ask your provider for your money back.
If you are in too much energy credit, your supplier may reduce your monthly payments going forward - which could help you save a bit more cash.
You can contact your energy provider over the phone, through email, over social media or through your supplier's online chat.
