The Big Switch and Save collective switching scheme being run by Norwich City Council will see people pay on average at least �156 a year less on their energy bills.
A total of 1,768 households signed up and an auction saw the Norwich group joined with four other British collectives to get the best deal.
Ovo Energy are offering to supply energy to online billing-only customers. Dual fuel customers will save on average �176 a year and electricity-only customers �165 a year.
While Co-operative Energy are offering to supply to paper billing customers. Dual fuel customers stand to save on average �156 a year and electricity-only customers �182 a year.
The city council's environmental strategy manager, Richard Willson, who is responsible for the project, said: 'This is a fantastic result. We have shown beyond a doubt that this scheme really can save a meaningful amount of money for people living in the city.
'The only thing left to do now - and it's the most important thing of all - is to make that final switch.
'Once you have received your offer and established you can save money, you need to respond either by letter or online by the deadline to actually make the saving a reality.'
The deadline for offline acceptances - accepting by letter or with assistance from the city council - is Friday, December 14 and the deadline for online acceptance is Wednesday, December 19.
The city council is now planning to run another collective switching scheme in the new year.
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