Gas and electricity customers will receive automatic compensation of £30 from May if their switch to a new provider goes wrong, Ofgem has said.
The regulator said the new rules should give "peace of mind" to those shopping around. More than six million people switched energy firms last year.
Payments will be made if the switch is not completed within 15 working days.
A mistaken switch or a failure by the old supplier to provide a final bill within six weeks will also qualify.
