10 cheapest gas suppliers compared: switch & save!

Cheapest gas supplier

Working out the cheapest gas supplier can be a tough task. With so many factors at play, it can sometimes seem difficult to know where to start when seeking out the best deal for your home. Here at Selectra, we make things simple by comparing the cheapest gas suppliers on the market, so you don’t have to.

Looking for a great deal on your electricity instead?Check out our guide to the cheapest electricity suppliers and find a tariff that works for you.

Understand your bill to find the cheapest gas supplier

To work out exactly which gas supplier is cheapest, we have to first understand the various charges that make up our energy bill. Although jargon like ‘unit price’ and ‘standing charge’ may not mean much to you, understanding and comparing your tariff is really a lot more simple than you may think. Let’s take a closer look at the charges that make up your energy bill.

1. Unit rate

This is how much you will pay per unit of energy. The unit rate is measured in kilowatt-hours (kWh) and will make up the largest percentage of your bill. Even if the unit rate is fixed, your overall charge at the end of the month is based on how much energy you use. Therefore you’re likely to see higher bills in the winter and lower costs in the summer.

Gas unit rates are a lot lower than their equivalent electricity units. This is because it takes a lot more gas than electricity to achieve the same result. While the average household electricity consumption is 2,900kWh per year, it’s 12,000kWh for gas.

2. Standing charge

The standing charge is a daily fee to cover energy supply and maintenance costs, therefore keeping you connected to the national gas grid.

Unlike the unit price, the standing charge remains the same, regardless of how much gas you use.

3. VAT

The final charge applied to your gas bill is value added tax. In 2020 this stands at 5%, applicable to both gas and electricity costs. Some providers and energy comparison sites will not include this when giving you a quote, so make sure you take this into consideration when looking for the cheapest gas supplier.

Confused by your energy bills?Don't let confusion get in the way of saving money on your bills. Call us for a free assessment today. Call 01704 335 575 or get a free callback now.

What types of gas tariffs are there?

Now we know the charges that make up our bill, let’s move on to the types of tariffs you’re likely to come across when comparing gas suppliers and how they differ from one another.

Fixed gas tariffs

A fixed tariff guarantees the same standing charge and unit rate locked in for the duration of your contract, even if wholesale gas prices fluctuate. However, although these charges remain constant, keep in mind that this doesn’t mean you will be billed the same amount each month, as that depends on how much energy you use.

Usually, fixed tariffs are guaranteed for a period of one year or more and include a penalty charge if you decide to change tariff or switch provider during your contract, known as an exit fee. These can range from £15 up to £100, so it’s always worth checking this first if you are thinking of switching to a cheaper gas supplier.

The cheapest gas suppliers usually offer fixed-rate tariffs and these can often work out as the most affordable option, as you will see from our comparisons further down the page.

Variable gas tariffs

Rates on a variable tariff, on the other hand, can change from one month to the next as the wholesale cost of gas fluctuates. While you might think you’ve signed up for the cheapest gas tariff on the market initially, that may not always remain the case a few months down the line.

If the rate does change, your provider is required to notify you of significant increases at least a month before, which means you have time to change tariff or switch provider.

One way you can end up on a variable tariff without even knowing is if you let your gas plan come to an end without taking any action. In this case, your supplier will automatically move you on to a standard variable tariff.

These are usually among the most expensive rates your supplier will offer, so we recommend doing some research ahead of time and having a new tariff or energy provider lined up before your contract ends.

Prepayment gas tariffs

Prepayment tariffs allow the customer to pay upfront for their gas either online or by using a key or card. The main advantage of these tariffs is never receiving unexpected charges or bills in the post, as you only pay for the energy you use.

However, this type of plan generally comes with more expensive unit rates, as well as a standing charge which is also expected to be covered upfront.

Calculating your gas billTo calculate your annual gas bill and see how it compares against other tariffs, simply multiply your energy consumption by the unit rate and add 365 days of standing charges. For a more detailed breakdown and examples, see our guide on how to compare gas prices

Which is the cheapest gas supplier in the UK?

Magnifying glass and energy bill

Now we have a better understanding of our energy bill, let’s get down to working out which is the cheapest gas supplier on the market. Firstly, we’ll compare the 10 cheapest fixed and variable rate tariffs, before moving on to prepayment plans.

As location and energy use are the key factors in relation to how much you should be paying, it can be difficult to determine the exact cost of a particular gas tariff. However, to give an idea of what an average UK spend may be, we have worked out the annual costs for a medium-sized household of three in the South East of England using an average 12,000kWh of gas per year.

These tariffs should give you an idea of which could be the cheapest gas supplier for you. However, the only way to know for sure is by speaking to an energy expert about your own situation. Call us now for free on 0170 433 5575 to compare energy providers and find out which could save you the most money.

All tariffs below are paid by monthly Direct Debit. As mentioned above, variable tariff rates can change over time. Therefore, they may not end up working out as cheap as in our comparison table, should the wholesale price of energy change during your contract.

Top 10 cheapest gas suppliers
Supplier Tariff Fixed-rate or variable Gas annual cost Exit fees?
Zog Energy Mercury 12 fixed Fixed for 12 months £370.66 £30
Outfox the Market Pure Gas 2.0 variable Variable £372.90 No
Bristol Energy BE Simply Green Fixed for 12 months £383.70 No
iSupply Energy Discover Green Fixed for 12 months £384.07 £30
Green Star Energy Fix for Less paperless Fixed for 12 months £384.74 £30
Gulf Gas & Power Gulf Home Renewable Fixed for 13 months £384.98 £30
So Energy So Alder Green Fixed for 12 months £386.49 £5
Green Network Energy GNE Family Green Fixed for 12 months £401.78 £25
Affect Energy Affect 12M Fixed Fixed for 12 months £404.09 No
SSE Online Energy Fixed for 12 months £404.72 £30

*Information correct as of May 2020. All quotes are tariffs paid monthly by Direct Debit and based on comparison for a three bedroom house in London with an average annual gas consumption of 12,000kWh.

The results are in, and Zog Energy leads the way with its Mercury tariff coming in at just over £370 a year in our tests. In second place is Outfox the Market’s Pure Gas plan, though it should be noted that this is a variable plan, so costs could actually rise or drop throughout the year.

Cheapest prepayment gas tariffs

Next up, we looked at the 10 cheapest gas suppliers for prepayment customers. While this may be a good option for those who need to budget ahead of time, customers on pay-as-you-go tariffs generally end up overspending on energy costs compared to those on Direct Debit plans. Therefore, it’s no surprise to see higher tariff prices here.

Top 10 cheapest gas suppliers - prepayment tariffs
Supplier Tariff Fixed-rate or variable Gas Annual cost
Omni Energy Omni Prepay Variable Variable £481.84
SSE Southern Electric Standard PAYG SMETS2 Variable £524.42
Bristol Energy Standard Prepay Paperless Billing Variable £528.64
E Energy 1 Year Reward Smart Variable £538.09
Green Network Energy GNE Prepayment V1 Variable £551.68
Spark Energy Move-In Saver 9 Variable £557.22
Robin Hood Energy Evergreen Variable £557.51
Ebico Ebico PrePay Variable £557.51
Angelic Energy Pay As You Go Variable £557.51
Beam Energy Pay As You Go Variable £557.51

*Information correct as of May 2020. All quotes are prepayment tariffs based on comparison for a three bedroom house in London with an average annual gas consumption of 12,000kWh.

Customers with traditional prepayment meters may need to have a smart meter fitted instead to make the most of these deals. Energy providers are currently installing these free of charge for eligible customers as part of the government’s smart meter rollout.

Switching to a smart meter also saves a lot of hassle if you choose to move on to a Direct Debit plan further down the line. Instead of having a new meter installed, you can simply contact your energy provider and ask them to remotely switch your smart meter from prepayment to credit mode.

Could a smart meter help you save money on your gas and electricity bills?Call one of our advisers to find out how much you could save. Call us for a free assessment today. Call 01704 335 575 or get a free callback now.

Does choosing the cheapest gas supplier mean worse customer service?

Of course, when choosing a new gas supplier you’ll want to take more than just cost into account - after all, what’s the use in being with the cheapest gas supplier if its customer service is terrible?

Many of the cheaper tariffs on our list are offered by smaller suppliers. The reason they are able to do so is that they tend to operate with far lower overhead costs than traditional large energy providers, such as British Gas, E.ON and Scottish Power.

Fortunately, this doesn’t necessarily mean compromising on customer service. You may be surprised to learn that many of these smaller suppliers actually rate higher on trusted consumer websites such as Which? and Trustpilot.

To learn more about which gas supplier could be right for your home, take a look at our energy provider guides, where you’ll find reviews, tariff prices and more. Alternatively, you can give us a free call on 0170 433 5575 and speak to an energy expert about your options today.

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