E.on has launched a new tariff which charges a fixed monthly bill, regardless of how much energy you actually use - but it's not cheap.

The new tariff - E.on's Secure Bill - promises to charge users the same amount each month for a year, it provides a quote based on how much they used over the previous 12 months.

But it doesn't come cheap - in fact according to figures we've seen it works out as E.on's most expensive tariff for typical use.

Based on the average household dual-fuel bill it'd cost £1,224/yr (£102/month), whereas the cheapest fixed tariff on the market currently costs £867/yr, so E.on's new tariff works out over £350/yr more to guarantee a monthly price.

Although the concept is unusual, it is not unique as Green Star Energy has offered a similar 'unlimited' tariff since 2015.

Save £100s/yr using our free Cheap Energy Club to compare prices and find the best deal for you.

How does the tariff work?

In order to get a quote, you'll need to provide E.on with the amount of energy you used over the previous 12 months - you can usually find this on your bill.

It will then provide you with a monthly price, which is calculated based on the region that you live in.

This price is then fixed for the next year, regardless of how much energy you actually use.

In comparison, other tariffs charge a set amount per kWh unit of gas or electricity plus a daily standing charge, which means the amount you pay overall can fluctuate based on how much energy is used.

E.on's Secure Bill tariff is available to residential customers who pay by monthly direct debit, and have dual-fuel or electricity-only. It's also available to those with economy 7, though economy 10, gas-only and prepayment customers can't get it. It's also worth noting it has a £75 exit fee for each fuel (though as with all suppliers you can switch penalty-free within the last 49 days of your fix).

Customers signing up to the tariff must agree to smart meters being fitted, though if E.on can't fit one, you can still get the deal. See our Smart Meters guide for more info.

What if my energy usage dramatically changes?

E.on says that bills won't rise even if energy use increases, meaning that in theory you can use as much as you like while still paying the same price. Equally though, bills won't decrease if you use less than stated.

E.on says that it's important for customers to provide previous consumption values to accurately predict a price, and it could ask to see copies of your previous supplier's bills to confirm this. Its terms and conditions also state your price could change if it becomes aware that any information you provided at the time of your quote was inaccurate.

It has however confirmed there is no fair usage policy in place, though it has stressed that this is a new tariff and terms may be updated in the future.

We asked what happens if circumstances change, say you start a family or someone moves out of the family home. E.on said if your circumstances change during your fix and you suddenly use a lot more energy, you can remain on the tariff - as long as you gave an initial accurate figure for the previous 12 months. On the flip side if you use dramatically less because of a change in circumstance you can switch to another of E.on's tariffs penalty-free.

The tariff is also not portable, so cannot be taken with you if you move.

How does the tariff compare to others?

Based on average use, E.on's new tariff costs considerably more than the current cheapest. It's also higher than E.on's standard tariff - making it the most expensive tariff it currently offers. Based on typical use, even if you were to use 30% more energy, you'd still pay less overall by opting for the cheapest deal.

How does E.on's Secure Bill tariff compare?

Tariff Type Cost/yr
E.on Secure Bill 12 month fix £1,224
E.on standard tariff Variable £1,208
Cheapest fix on the market 12 month fix £867
Cheapest variable on the market Variable £853
Tariffs correct at 9 Aug 2018. Based on UK typical dual fuel usage and payment by monthly direct debit.

Energy prices always vary depending on where you live and how much energy you use, so to get the best tariff always do a comparison using our free Cheap Energy Club.

In order to compare if this tariff would work for you, use these prices as a benchmark against the quote from E.on, which you can only get by calling it directly.

What does E.on say?

Michael Lewis, chief executive of E.on UK, said: "E.on Secure Bill marks a significant shift towards making energy more personal by offering people the ability to set in stone how much they’ll pay each month based on an accurate reflection of how much they used in the past 12 months.

"Unlike other fixed term tariffs which are available today, Secure Bill means customers' payments won’t change during the year, regardless of how much energy they use. This gives customers complete reassurance about how much they’ll pay each month for 12 months and the ability to accurately budget for their energy."