Energy glossary

Ever looked at your energy bill and felt confused? It can be hard to understand your bill but Ofgem has worked hard to simplify it.

But if you’re still confused, this jargon buster can help. Arm yourself with this know-how and you'll be able to decipher the most baffling of bills.

Billing Period

This tells you what period the energy bill covers. It's usually 3 months. However it’s usually more helpful to look at the annual allowance when you’re comparing energy deals.


This is how some suppliers measure your energy and then convert the electricity and gas into kilowatt hours (kWh)

Dual Fuel

This is when one supplier manages both your electricity and gas. They usually offer a discount for this, but it may not necessarily be the cheapest option.

Actual/Estimated Reading

This tells you if your bill is based on an estimated or actual reading. It's always best to get an actual reading as this stops you under or overpaying.


Every supplier has their own tariffs and plans. This determines how much you are paying per kWh. If you're on a plan it will have a name and you'll need that information if you want to compare your deal with other companies. The most common plans are...

  • Fixed Tariff: your price for kWh is fixed for a set period
  • Variable Tariff: your rate can go up or down at any time

Look out for the name of your plan on your energy bill, and also the date it ends.

Exit Fee

Some suppliers will charge you an exit fee if you end a plan early. You should look for the end date on your bill to check if you might be tied in.

Standing Charge/No Standing Charge (NSC)

A standing charge covers the cost to provide energy to your home. Both electricity and gas have their own charge, even if you have a dual fuel account. It's basically a supply upkeep charge. Part of this charge also goes off to government incentives to reduce carbon emissions and to help the vulnerable keep warm so it doesn't all go to the supplier. All tariffs include a standing charge, but some plans may have no fee – it will still say 'standing charge' on your bill but the amount will be set at £0.


These are your Meter Point Reference Number and your Electricity Supply Number (or sometimes known as S number). Don’t worry too much about what they mean, you just sometimes need these to switch suppliers.


This will change depending on how your bill stands after they've taken into account your payments against what you've used. At some point in the year when the supplier reviews your usage you'll get an adjustment to your payments. If you're in credit you could get some money back, or your payments could decrease. If you're in debit, you can expect your payments to go up.

Personal Projection

A report from Ofgem (the energy suppliers’ regulatory board) outlines that energy suppliers must make their information clearer and helpful. One of the requirements is that along with your bill they give a Personal Projection – this predicts what the provider believes you'll use and pay over the next 12 months, based on your previous usage.


Electricity and gas VAT is fixed at 5%...for now.

Some General Terminology...

Renewable Energy

This is simply power that can be produced by natural resources that won't run out or damage the environment. Any of us can install solar panels and wind turbines (subject to planning). The energy generated is cheap (or free) but the outlay is expensive so it can take a few years to recoup it back so make sure you consider the long- and short-term costs before going ahead.

The Big Six

These are the six main energy suppliers: British Gas, EDF Energy, E.ON Energy, npower, Scottish Power and SSE.

Economy 7 & 10

A creation of the 1980s and still around, Economy 7 provides you with cheaper electric overnight. It was originally designed for homes with storage heaters that would store up energy over seven hours at night. Economy 10 gives you an extra three hours of cheaper power. If you fancy being a night owl and doing all your washing, hoovering and cooking at night then this could work... although you wouldn't be too popular with your neighbours! As these tariffs aren't as common now you could also have trouble finding a good deal.

Smart Monitors

If your current energy provider offers you one of these for free take it... some people have to pay for them. They attach to your power supply and tell you how much energy your household is consuming in real-time, as well as giving accurate usage information direct to the supply, so your bill should always be accurate.