British Gas, EDF Energy, E.ON, Npower, Scottish Power, and SSE provide about 90% of the gas and electricity used in the UK.
But they do not always offer the best energy deals.
Most people could save money by switching from the so-called Big Six suppliers to a smaller energy company.
Who are the Big Six?
British Gas, EDF Energy, E.ON, Npower, Scottish Power, and SSE are the country's largest energy companies, or Big Six gas and electricity suppliers.
Does big mean best?
Not necessarily. While these six companies supply almost all UK households, smaller suppliers often offer cheaper deals.
They also tend to have higher customer service ratings.
That’s why our energy comparison service shows you tariffs from all the suppliers in the UK, not just the Big Six.
Who are the smaller energy suppliers?
Over the last five years or so, the number of energy companies in the UK has shot up.
The smaller, “challenger” suppliers include:
- First Utility
- Ovo Energy
- Utility Warehouse
- Good Energy
- Octopus Energy
Which company provides the cheapest electricity?
No one electricity supplier offers the cheapest deal for everyone.
The best deal for your home will depend on factors such as where you live, how much energy you use, and when you use it.
Which company provides the cheapest gas?
As with electricity, the cheapest gas supply for your home will depend on your individual circumstances.
The quickest and easiest way to find out is to compare deals on MoneySuperMarket.
What are the benefits of the Big Six?
Some people feel safer sticking with an energy company they know.
But Ofgem regulates all the UK’s energy suppliers, so smaller companies follow exactly the same rules as the Big Six.
Even if a smaller provider goes out of business, you will not lose any money and there will be no disruption to your gas and/or electricity supply (see below).
What are the benefits of changing to a smaller supplier?
As well as offering cheaper deals for many people, smaller energy companies often come out top for customer service.
Smaller green energy specialists, such as Ecotricity and Green Star Energy, also tend to offer the most competitive, environmentally friendly tariffs.
Are there any disadvantages to switching to a smaller supplier?
There are generally no disadvantages to switching to a smaller supplier.
However, if you receive the Warm Home Discount (a £140 payment towards your energy bills), it’s worth checking small suppliers pay this.
Only energy firms with at least 250,000 customers have to offer it, although some smaller firms still do.
What happens if a smaller supplier goes bust?
You will not be left without gas or electricity if your supplier goes bust.
Under regulator Ofgem’s rules, you will simply be switched to a new supplier if your existing company can no longer provide energy.
Your tariff may change, but you will not lose any in-credit balance you have. Find out more about your rights.
How long does it take to change energy supplier?
Your supply is not interrupted when you switch energy companies. And no work needs to be done on your home.
It’s the same gas and electricity coming through the same pipes and wires – just at a cheaper price!
Switching should therefore take no longer than 21 days, including a two-week “cooling-off” period during which you can cancel free of charge.
How do I change energy suppliers?
Finding a cheaper energy deal takes just a few minutes using MoneySuperMarket.
To do this, you will need:
- Your postcode
- A recent bill showing your supplier, your tariff, and how much energy you use*
- Your bank details (to set up a new direct debit)
- An up-to-date meter reading so your existing supplier can send you a final bill
*Our energy usage estimation tool can help if you don’t know this.
Can I switch energy suppliers if I am in arrears?
You can switch energy suppliers if you have been in debt for less than 28 days.
If you have owed money for longer than that, you'll need to repay it first.
The exception is if you have a prepayment meter, in which case you can switch as long as you owe less than £500 for gas and/or £500 for electricity.