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Cheapest gas suppliers compared: switch & save!

Scales weighing up the 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've made 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.

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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 though 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 (VAT). In 2021 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.

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.

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 supply 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 up front.

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 worth of standing charges. For a more detailed breakdown and examples, see our guide on how to compare gas prices

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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. 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 you an idea of what an average UK spend may be, see below for the average energy consumption figures in the UK, according to industry watchdog Ofgem. You can also use our Energy Consumption Calculator to get a clearer picture based on your own energy usage habits.

Average gas usage UK
Fuel Level of consumption Consumption
Gas Low (1-2 bedrooms/flat) 8,000 kWh
Medium (3-4 bedrooms) 12,000 kWh
High (5+ bedrooms) 17,000 kWh

You should compare prices based on your own location and consumption for the most accurate price projection.

Cheapest prepayment gas tariffs

While prepayment can be a good option for those who need to budget ahead of time, customers on pay-as-you-go tariffs generally end up paying more money for the same amount of energy as those on Direct Debit plans.

Customers who cannot afford to switch to a Direct Debit plan or those with debt may find it helpful to have a smart meter fitted to keep track of their gas usage. 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 can also save a lot of hassle if you choose to move on to a Direct Debit plan further down the line. Instead of having a new credit meter installed, you can simply contact your energy provider and ask them to remotely switch your smart meter from prepayment to credit mode.

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 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 and in Citizens Advice's quarterly customer satisfaction survey.

Citizen's Advice Customer Service Ranking: Top 10
Rank Energy Supplier Rating
1 Outfox the Market 4.25
2 M&S Energy 4.2
3 E Energy 4.13
4 EDF Energy 4
5 Octopus Energy 3.95
6 Zebra Power 3.8
7 Affect Energy 3.65
8 Co-Operative Energy 3.65
9 Bulb Energy 3.55
10 So Energy 3.35

Information from Citizen's Advice Last Updated October 2021

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 customer reviews, contact information, tariff prices and more.

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The services and products mentioned on this website may only represent a small selection of the options available to you. Selectra encourages you to carry out your own research and seek advice if necessary before making any decisions. We may receive commission from selected partner providers on sales of some products and/or services mentioned within this website. Our website is free to use, and the commission we receive does not affect our opinion or the information we provide.