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Do you think you could beat our tariff test?

Energy tariffs in petrol pump style

We found only one in 10 people could identify the cheapest deal when presented with a range of standard energy tariffs. When shown the tariffs in a simpler form the number shot up to nine out of 10.

Imagine pulling up to a petrol station and instead of seeing that the cost of your petrol is going to be around 142p per litre, you’re presented with a baffling array of figures that are all displayed and calculated differently.

You could have a fixed charge and then add the price per litre on top, or you could have different levels of price per litre determined by how much you fill up. Once you’ve decided this, you then need to work out if you’d be better off on a ‘standard’ deal, or if fixed or variable deals are the way to go. Think it’s a good idea? I thought not. Just imagine the queues!

Gas and electricity pricing

So why do we have this complicated, confusing system for our gas and electricity? The latest investigation from Which? shows that only 8% of people could work out the cheapest tariff when presented with six energy deals. The energy suppliers have each adapted their tariff and pricing structures for their own deals so what we’ve been left with is a market that’s now so complicated it’s nearly impossible to find the cheapest deal.

So, it’s hardly surprising that most people don’t even bother trying to find out the best deal for them, even though some could save hundreds of pounds each year.

We think that consumers have the right to simple, easy-to-compare gas and electricity prices. Why can’t it be simpler? If it was more like petrol pricing, and we had one unit rate we could easily compare all gas and electricity deals at a glance.

Price rises bump up bills

With headlines warning us of higher energy bills, and British Gas and Npower announcing price rises this week, it’s even more urgent that we can work out what the cheapest energy deal is.

Ofgem, the energy regulator, has spent two years reviewing tariffs to try to help you switch to get a better deal. It has promised to be bold and force energy suppliers to cut down on the unnecessary complexity. The question is, will it make the ‘bold’, but necessary, reforms or will it simply cave in under the pressure from industry?

If we don’t get the results we’re looking for, we’ll be demanding that the government steps in to simplify the market once and for all.

Roger Pask says:
31 October 2012

I organised a switch through USwitch web-site and filled in the forms including current usage both day and night (3600 kWh p.a.) and was immediately given a number of options which would ‘save me money’. I signed up to shift from Scottish Power to EDF on the basis of the recommendations. In a subsequent email from the web-site I noticed that the savings trumpeted had an asterisk. Digging around in the small print I discovered that the savings were on the basis of my using only a spurious 2032 kWh which bore no relationship to what I had told them and in fact offered an increase in costs as far as I could see. I complained. They then said ‘OK Switch to this instead’ – a seemingly random response to yet another supplier.
If these web sites are misleading potential switchers – telling them they could save money if you used less (rocket science) but letting them think they are offering genuine benefit – and then pocketing money from the big 6 for organising a switch; then they also need taking to task along with the rest of what is, apparently, an increasingly grubby industry.

Clive says:
3 November 2012

I am not able to benefit from duel fuel tarrifs as I am on LPG and mains electricity. I only wish I could pay mains gas prices. My gas usage (2 people, 3 bed house) is around 3500 litres a year and at the present price I will be paying about £170 per month. I have just moved my electricity to a fixed rate (before the price rises) and pay just over £40 per month.
Can you please tell me how I can compare therms or energy efficiency between LPG and electric? The price for gas is 58.90pence per litre and electric is based on units. In other words, should I heat my boiler with with my immersion heater or should I continue to use the gas (condensing) boiler and should I try to use one fuel over another whenever possible?


LPG has always been the most expensive fuel, but of course you also have the storage tank too. Oil has an undeserved reputation for high price, but of course, you need a tank etc.
To compare prices accurately you must work in terms of calorific value for each fuel. By law this has to be provided for each fuel, but you’ll need good arithmetic to convert them all to comparable units. suggegest kW hours. ! litre of oil at present 70p yeilds about 10 kW hrs depending on boiler


Clive, as I understand it the calorific value of LPG is around 25 MJ/litre. As 1 MJ (Mega Joule) is equivalent to 0.28kWh, 1 litre of gas = 7 kWh. 1 kWh (kWatt hour) is one unit of electricity. So your litre at 59p is equivalent to 7 units at say 14p = 98p of electricity. Assuming your boiler is a high efficiency one I’d stick with gas, providing your water temperature is controlled as well with either fuel. Hope your tank is also well insulated.

Andrew Sangster says:
4 November 2012

Comparing the different tariffs isn’t difficult, but it is time consuming and life is too short to spend time regularly trawling through the options, even with the help of the excellent web services such as Which’s (I used it recently to shift supplier). I don’t mind there being tariffs that provide a lower average charge for different levels of usage, or there being discounts for online billing or loyalty, but there should be a straightforward way of viewing the charges from each supplier in a standard format. At the moment you have to go through a full quote even to see the kwh charges. So, don’t push for oversimplification, but do push for a standard format that has to be readily accessible.

Colin says:
7 November 2012

I can fully endorse the move for simplifying tariffs and more transparency, but I am worried that those of us on specialised, favourable tariffs (I am on one for ‘wet’ electric central heating where the central heating only is on its own dedicated tariff with highly competitive rates) get overlooked and could end up with vastly increased bills because we are put on one of the fewer simplified tariffs designed for the mainstream.


If your wet heating uses off-peak electricity to store heat for use during the rest of the day then you should keep a lower tariff – the generators need load during the night to make economical use of their plant, and the incentive should be lower unit charges.
There is not be much scope to use off-peak other than heating, washing, dishwashers. In my case. and I suspect many others, the possible load is not sufficient to make Economy 7 viable – I need 40-50% of my load in the small hours to make it cheaper (on Economy 7, daytime units cost more than a standard tariff).
We should all be encouraged/educated to use higher-power appliances off peak where possible to use this excess capacity – but there needs to be an incentive. Just abolish Economy 7, keep the normal daytime tariff and apply an off-peak tariff for whatever units are used by everyone.


Ah ha! Garbage in – garbage out…
TARIFF ERRORS on the WHICH? Switch service render price comparisons meaningless.

I have used the Which? Switch service over the last couple of years to check the latest deals on gas and electricity. With their help, I’m now with Ovo Energy on a dual fuel fixed tariff that’s due to
expire in mid November 2012.

Thanks to Ovo’s clear pricing, my total annual consumption data, energy costs and tariff rates are
very easy to work out and codify. Having carefully entered accurate details about my current tariff
and energy consumption data on the Which? Switch comparison site, I noticed that their tariff data
(i.e. the fixed charge rates for gas and electricity and the standing charges) are inaccurate. In effect, these data errors translate into estimates of my total energy consumption that are £58 dearer than they really are.

Now, being £60 adrift isn’t a big deal in the greater order of things, but when you take into account
that three energy suppliers are competing for my custom within a margin of about £50, you
will appreciate that the Which? Switch calculator is only as good as the data held in it.


Hi Peter,

I work on Which? Switch and first of all I’m sorry to hear you’ve had problems with a quote from the service!

The way that Ovo structure their tariffs means that we have a lot of different versions with different prices and similar names. I think the most likely reason for the difference you’re seeing is that you’ve selected a different version of their tariff from the dropdown on the current situation. Can I ask when you signed up? Because they regularly release new versions of their fixed tariffs without changing the name, we have to list each new version by the dates it was available to sign up for new customers, which can mean the list looks a little clumsy.

We regularly check our pricing against both suppliers’ ‘average bills’ and other comparison websites, and as part of our accreditation from Consumer Focus we are audited for our accuracy on a quarterly basis- so we really do our best to make sure the quote you get is as accurate as possible.

Again, I’m very sorry you’ve had problems with the service. If you have any further issues then you can always email wsqueries@which.co.uk and we’ll investigate any problems.


The cost savings predicted by an energy switch calculator are critically dependent on the accuracy of the tariff data they hold. Recently, I put a few energy switch services to the test, including Which Switch, uSwitch, and energylinx. All of these comparison sites displayed either incorrect information about the unit rates (p/kWh) for the gas and electicity that I am currently paying for or incorrect standing charge rates (pence per day). In some cases both the unit rates and the standing charges were incorrect. All of my figures were adjusted for the 5% VAT.

At best, these errors, no matter how small, will give a false impression about the savings that a consumer can enjoy, if any savings really exist at all. At worst, they will create more cunfusion and mislead.

larry Levin says:
14 November 2012

Uswtich discounts and “savings” are an illusion, the discounts assume that prices the spread between one provider and another does not change.

Mike P says:
11 November 2012

It worries me that only 8% of people could work out the best deal from your examples in the November Which. Is our education system so bad?
I don’t have a maths degree, but it took me just 10mins to work out the correct answer.


@ Mike P.

As a maths graduate, who did teach maths for several years, I have to tell you that the number of people who can do even the most basic maths without step-by-step instruction on each occasion they do it, is very small.

The greatest problem is that we have at least a generation of Grandparents, a generation of parents and a generation of students, who are all resistant to learning any maths and who are frightened of maths.

The most common cry from parents when I was teaching maths was “Oh (s)he̵