Our advice is not to switch immediately, but wait until Octopus Energy has been in touch with you. They will contact you by 14 August 2018 with personalised information about your tariff.
Your switch to them will be completed around 21 August 2018. Octopus Energy will email you at this point to confirm once this has happened, and from then on you'll have full access to your Octopus Energy account. If you try to switch away from Octopus Energy before they complete the transfer of your account, the switch may not proceed or take longer to complete.
Once you have been contacted by Octopus Energy, you can then shop around or ask them to put you on a different tariff. You won’t be charged any exit fees. Waiting for them to contact you will be the smoothest way to have any credit balances you had with Iresa honoured by Octopus Energy.
For clear advice on how to shop, see our guide: How to switch and shop for a better deal.