Switching energy supplier takes about 21 days and costs nothing. But before you do it, a few minutes of preparation will make sure you actually end up better off rather than just different.

1. Your current unit rate and standing charge

You need both of these to compare properly. The unit rate is what you pay per kWh of electricity or gas. The standing charge is the fixed daily fee you pay just to be connected, regardless of how much you use.

Find them on a recent bill or in your online account. Without these two numbers you are comparing blind.

2. Whether you have an exit fee

Standard variable tariffs usually have no exit fee, so you can leave any time. Fixed tariffs often do, typically between £50 and £150 per fuel. Always check before you switch or you could wipe out any saving before you have even started.

If you are mid-contract on a fix, work out whether the saving on the new tariff outweighs the exit fee over the remaining months.

3. Your annual usage in kWh

Most comparison sites ask for this figure because it gives you a like-for-like cost comparison rather than just a headline unit rate. A tariff with a cheap unit rate but a high standing charge could end up costing more if you are a low user.

Find your annual kWh figure on your bill or smart meter account. If you do not have it, most suppliers will estimate based on your property type.

4. Whether the new tariff has a smart meter requirement

Some tariffs, including Agile Octopus, require a smart meter to work properly. Without one your supplier cannot read your half-hourly usage, which means you cannot access time-of-use pricing.

If you do not have a smart meter, most suppliers will arrange a free installation as part of the switch. It usually takes a couple of weeks to book in.

5. The standing charge on the new tariff

A low unit rate with a high standing charge can end up costing more than it looks, especially if you are a low energy user. Always factor in both numbers when comparing.

For context, the Ofgem average standing charge for electricity for April to June 2026 is 57.21p per day. That is over £208 a year before you have used a single unit. Some tariffs sit above this, some below. Always check.

Worth knowing

Once you have done your homework, switching itself is straightforward. Your new supplier handles everything and there is no disruption to your supply. If you want to try Agile Octopus, use my referral link and we both get £50 credit when you switch.