Small firms need more help with their energy contracts as many are confused over new rules brought in by Ofgem, according to business price comparison service Make It Cheaper.

Different interpretations of the new rules - which give small businesses the right to opt out of seeing their contract be rolled-over by energy companies - by the main business energy suppliers means no two contract termination 'windows' are the same.

These windows - in which businesses must serve notice to avoid having their contracts automatically renewed - are as narrow as 30 days and may have already closed as much as 90 days before the contract end date.

Data shows that over 80% of businesses do not know when their energy contracts come to an end and so usually end up being 'rolled' by their existing supplier.

"The key to switching, regardless of any variation of the rules, is to find out when your current contract ends and how much notice you need to give in order to be eligible for the best rates," said Jonathan Elliott, managing director of Make It Cheaper.