The Huge Switch campaign from energyhelpline.com has been extended by four days so people have more time to compare electricity prices.
So far, consumers have saved over £1 million using the initiative and it has reduced typical bills to less than £1,000.
It will now close on Friday June 1st at 4pm.
Director at energyhelpline.com Mark Todd said the supplier is proud to offer these savings to gas and electricity customers.
The initiative makes it cheaper for people to switch providers and find the best deals.
Mr Todd added: "What better way to start the Jubilee weekend than with the knowledge that you have saved hundreds of pounds on next year's energy bills?"
The cheapest tariff available from Huge Switch costs £61 less than the best Co-operative Energy deal through Which?'s Big Switch campaign.
Make sure you're not paying too much for your energy - compare gas and electricity prices now at energyhelpline.com or call 0800 074 0745