Energy ratings from A to G are based on EU standards and are used to rate energy efficiency and energy saving potential. "A-Rated" indicates the highest performing and best at energy saving. An "A-Rated" appliance will be the most energy efficient and could save money and reduce impact on the environment.

Account holder

The account holder of a British Gas business account. The account holder can be an individual or business name and will appear on the front of an energy bill. See an example of a British Gas business bill.

Account number

The unique number for your British Gas business account. It will be displayed on the front of your bill or invoice. See an example of a British Gas business bill.

Actual bill

This is a bill based on an actual meter reading, as opposed to an estimated reading. An actual bill will accurately reflect your energy consumption for a defined period. To get actual bills, submit regular meter readings or use a smart meter.

Aggregations and de-aggregation in the gas industry

It used to be common practice to combine two or more gas meter points (MPRNs) to create an aggregated supply point. At the end of 2015, an industry change implemented a new NEXUS operating system which means there should be no more than one meter point for each supply point.

Industry modification 428, ‘De-aggregation of gas sites’, established this rule and has removed the practice of aggregating meter points into supply points for the purposes of calculating transportation charges. It’s no longer possible to add a meter point to an existing multi-metered supply point, or to combine single meter points together to create a new multi meter supply point.

Air conditioning

Using a refrigeration unit (powered by electricity or gas) to cool or dehumidify air in an enclosed space such as your business premises. Configuring air conditioning to optimum efficiency could help save energy.

Alternative fuel

A fuel which can be used as an alternative to fossil fuels such as oil and coal. Alternative fuels include biofuels, liquefied petroleum gas (LPG) and fuel cells. They are considered to have less environmental impact than fossil fuels.


A unit of electrical current.

Automated Meter Reading (AMR)

Reading or data collected automatically from meters and used for billing purposes. A British Gas business smart meter takes remote AMRs for use in actual bills. It also provides data for the analysis of energy consumption across different sites and locations.

Annual energy consumption

Your annual energy consumption over a 12-month period. Your business energy consumption is usually shown on the front of an energy bill in kilowatt-hours (kWh). To calculate your annual consumption, multiply the figure by 12.



Banking Automated Credit System (BACs)

The electronic transfer of funds. This is one of the ways you can pay your British Gas business bill.

Billing address

The address where bills and invoices are sent. This is not necessarily the address where energy has been used.

Billing period

The period when you'll be charged for energy consumption. This is the time between meter readings. It doesn't refer to the time when the bill was sent or when payment is due to be received. Your billing period will usually be set out in your contract terms. If no actual meter reading can be obtained, an estimated meter reading will be used for your bill.


Fuels produced from biodegradable material. Biodiesel fuels, for example, are typically made from oils such as soybeans, rapeseed, or sunflowers, or from animal tallow. Biogases can be produced from methane-rich sources such as landfill or sewage.


Biomass is degradable biological material which can be used to generate biofuels.


Device used to generate steam for power and processing, or hot water for heating and other business uses.

Boiler fuel

The energy used to power a boiler. Optimising the energy efficiency of a boiler could help save energy and reduce costs.


An intermediary arranging the sale and purchase of energy supplies and other services between customers and energy suppliers.



Calorific value

The amount of heat generated when a given mass of fuel is completely burned. You can calculate energy use in kilowatt-hours (kWh) by converting it from its calorific value. See ‘Combined energy conversion formula’ for converting gas units into kWh.

Carbon dioxide (CO2)

A gas produced by fossil-fuel combustion, as well as other natural processes. It’s a normal part of the Earth's atmosphere. CO2 is considered a greenhouse gas as it traps heat in the atmosphere and contributes to global warming.

Carbon conversion factor

Used to calculate the amount of carbon dioxide (CO2) produced from energy use. According to the Carbon Trust, natural gas has a conversion factor of 0.185 e.g. 1,000 kWh of gas used is responsible for the production of 185kg CO2 (0.185 x 1000 kWh).

Carbon footprint

The impact human activities have on the environment. This is measured by the amount of greenhouse gases (usually carbon dioxide) produced by a particular activity.

Carbon intensity

The amount of carbon by weight (e.g. grams) emitted per unit of energy consumed (e.g. kilowatt hours).

Carbon monoxide (CO)

Carbon monoxide is produced from the partial combustion of carbon-containing compounds such as gas. It’s silent, colourless, odourless and potentially lethal. To minimise the risk of carbon monoxide exposure you should use Gas Safe registered engineers to install and service your gas appliances, such as your boiler. All businesses have a responsibility to ensure appliances meet the Gas Safety (Installation and Use) Regulations 1998 and the Health and Safety at Work Act 1974.

Carbon Trust

An independent company funded by the government to help the UK move to a low carbon economy. It works with organisations to reduce carbon emissions and develop commercial low carbon technologies.


Centrica is the parent company of British Gas business. It’s a top 30 FTSE 100 company with growing energy businesses in the UK, North America and Europe.

Climate change

Used to indicate significant change from one climatic condition to another. It’s also often used to refer to global warming.

Climate Change Levy (CCL)

A government charge on UK non-domestic fuel. It was introduced in 2001 to encourage businesses to use less energy and to contribute to the reduction of carbon dioxide emissions.

Combined energy

Refers to more than one energy type. For example, a British Gas business quote for combined energy would be a quote for both gas and electricity. Also referred to as dual fuel.

Combined heat and power (CHP)

Producing two forms of energy, such as heat and electricity, from a single source. For example, the steam produced from boiling water could also be used for industrial heating. A CHP system can be more efficient and offer energy savings as waste heat is not discarded and carbon dioxide emissions are reduced.

Connections and metering

The British Gas business service which connects a new or increased energy supply to business premises. The service provides expertise to organise every aspect, meaning that a business doesn't waste its own time on sorting out a new connection.

Contract price

The price for your energy consumption, as agreed in your contract. This could be a fixed or flexible price depending on your type of contract.


The Council for Registered Gas Installers (CORGI) used to be the national watchdog for gas safety in the United Kingdom. It was replaced by the Gas Safe Register in 2009/10. You should use a Gas Safe registered engineer for any gas, plumbing, heating or electrical work.

Correction factor (CF)

Used to convert gas units into kilowatt-hours (kWh). The correction factor (1.02264) takes into account changes in the volume of gas based on temperature and pressure. See ‘Conversion formula’ for converting gas units into kWh.

Conversion factor

To convert gas units into kilowatt-hours (kWh), two conversion factors are needed: an imperial to metric conversion factor (2.83) and a kilowatt-hour conversion factor (3.6). See ‘Conversion formula’ for converting gas units into kWh.

Conversion formula

Used to convert gas units into kilowatt-hours (kWh). The formula is as follows: gas units used x correction factor (1.02264) x imperial to metric conversion factor (2.83) x calorific value (38.9) divided by kilowatt-hour conversion factor (3.6) = kWh in cubic feet. To calculate a bill, multiply kWh in cubic feet by the unit price in your agreed contract.

Cubic foot (cf)

A unit of measurement for natural gas.

Customer reference number

A unique reference number used for your British Gas business account. It will be displayed on the front of your bill or invoice, and on any other correspondence related to your account (e.g. bill enquiries).



Dial meter

An older type of electricity meter. The meter display has a series of dials similar to a clock face, except that dials move both clockwise and anti-clockwise.

Diaphragm meter

A gas meter used in small commercial and industrial applications. These meters usually have a long working life and require little maintenance.

Digital meter

An electricity meter with a digital reading display screen.

Distribution network operator (DNO)

One of the 14 regional distributors responsible for maintaining the electrical network in the UK. Any new connection must be organised through your local DNO (British Gas business can help you do this). All DNO charges are regulated by Ofgem.

Dual fuel

Indicates the supply of more than one energy type e.g. gas and electricity. Also known as combined energy.



Electricity Central Online Enquiry Service (ECOES)

An online service provided jointly by electricity distribution and supply companies. ECOES notifies the relevant suppliers if you switch your electricity supply.


The release of gases into the atmosphere. Often refers to the emission of greenhouse gases, such as carbon dioxide, during fuel combustion.

Energy consumption

Use of energy as a source of heat or power. Your energy consumption will be measured by your gas or electricity meter and you’ll be billed for the amount you’ve used.

Energy efficiency

Reducing energy consumption while still maintaining similar levels of output or performance. This is usually achieved by reducing wasted energy or increasing the power efficiency of appliances. There are many things (big and small) you can do to save energy or improve energy efficiency.

Energy management

The monitoring and analysis of energy consumption. This can involve comparing usage, reducing wastage or optimising energy efficiency. British Gas business smart meters are one clever way of helping manage your energy consumption.

Energy supplier

The company supplying electricity, natural gas, fuel oil, kerosene, or LPG (liquefied petroleum gas) to your business.

Energy trading

The buying and selling of energy to take advantage of fluctuations in the energy market. Depending on your contract type and business size, British Gas business energy trading teams can help you to benefit from energy trading.


The independent gas and electricity watchdog. It provides free and impartial advice to customers.

Estimated bill

A bill based on an estimated meter reading (as opposed to an actual reading). This bill will reflect your estimated energy consumption for a defined period. We use estimated readings if we don’t have an up-to-date reading or if our meter readers cannot gain access to the premises. Remember that you can quickly and easily submit your own meter reading online.

EU Emissions Trading Scheme (EU ETS)

A European Union scheme to reduce emissions of carbon dioxide and other greenhouse gases in order to meet targets set out in the Kyoto Protocol.

Evergreen contract

A contract which is renewed at regular intervals. At the renewal date you can let the contract continue or give notice to leave.


The search for energy sources to ensure a sustainable and diverse supply of energy for the future. This can involve both exploration for fossil fuels and for alternative fuel sources, such as wind energy.




A passageway or pipe for directing products of combustion to the atmosphere.

Fluorescent lights

Usually made from long, narrow, white glass tubes coated with fluorescent material, fluorescent lights use less energy and have a longer life than traditional filament light bulbs.

Fossil fuels

Fuels such as coal, oil and gas which have been formed from the decomposition of ancient plant and animal matter.


The obstruction of the flow of energy from the fire or flue in a boiler. Fouling in boilers can have a significant effect on energy efficiency.

Fuel cell

A device capable of converting the chemical energy of a fuel directly into electrical energy. The chemicals used are usually very simple, often just hydrogen and oxygen. As the conversion involves an electrochemical process, not combustion, the process is often considered to be more energy efficient and to have less of an environmental impact.

Fuel mix

The mix of fuels used to generate electricity. Electricity can be sourced from a variety of sources e.g. coal, gas, nuclear and renewable.



Gas Safety (Installation and Use) Regulations 1998

Government regulations controlling the installation and use of gas supplies and appliances. It aims to prevent injury to consumers and the public from carbon monoxide (CO) poisoning, fire and explosion.

Gigawatt (gW)

Electrical unit of power equal to one billion watts or one thousand megawatts.

Gigawatthour (gWh)

A unit of measurement for electrical energy equal to one billion watt hours.

Global warming

An increase in the Earth's surface temperature. Global warming has occurred in the past as the result of natural influences, but the term is today most often used to refer to warming resulting from the emissions of greenhouse gases.

Green electricity

Electricity generated from renewable sources which are considered to have a low environmental impact e.g. wind or solar power.

Greenhouse gases

Gases such as carbon dioxide which trap heat in the atmosphere and contribute to global warming. Also known as the greenhouse effect.


The electricity transmission system for the UK.

Gross floor area

The total building area contained within the external walls of premises. If your floor area is quoted as net lettable area, then multiply by 1.33 to obtain the gross floor area.



Half-hourly data

A half-hourly meter records the amount of electricity used in a business premises in every half-hour period of the day. The meter automatically sends this data to your energy supplier.

If you’re an existing business customer you can request up to 12 months of half-hourly data.

Half-hourly online

A secure online management tool that displays your half-hourly energy usage data. It enables your organisation to accurately monitor your energy consumption and identify where efficiency could be improved.

Heating oil

A flammable, petroleum-based, liquid fuel, often used in furnaces.




A material or substance to prevent the flow of heat from one surface to another. Different types of insulation can include foam, loose fill, dead air space, lagging for hot-water pipes, or blanket insulation for boilers. Effective insulation can improve the energy efficiency of your business.

Interruptible energy supply

A contract where the supplier has the right to interrupt the energy supply to the customer, usually in return for a discount on price.



Joule (j)

A unit of measurement for energy, equal to one watt-second.



Kilowatt (kW)

A unit of measurement for power. A kilowatt equals one thousand watts.

Kilowatt hour (kWh)

A unit of measurement for electrical energy, equivalent to the power of one kilowatt operating for one hour. A bill from your current supplier will show your usage in kWh. To calculate your annual consumption, multiply the figure by 12.

Kilovolt ampere (kVa)

A unit of measurement for apparent power, equal to one thousand volt-amperes. To work out your peak energy usage in kVa, you’ll need to phone your energy distribution company.

Kyoto Protocol

The Kyoto Protocol is an agreement made under the United Nations Framework Convention on Climate Change (UNFCCC). The Protocol is the result of negotiations in Kyoto, Japan, in 1997. It sets binding greenhouse gas emissions targets for countries that have signed and ratified the agreement (such as the UK).



Landfill gas

Gas that’s generated from the decomposition of organic material at landfill disposal sites.


The lowest quality of coal, used almost exclusively as fuel for power generation. Also known as brown coal.

Limited Liability Partnership (LLP)

A business partnership in which the liability of all of the partners is limited to the capital they have invested.

Liquefied natural gas (LNG)

Natural gas that’s been liquefied by reducing temperature or increasing pressure. Its liquefied state means it takes up less space and can be stored and transported more easily.

Liquefied petroleum gas (LPG)

A natural hydrocarbon fuel largely made up of propane and butane. A gas at atmospheric pressure, it is liquefied by reducing temperature or increasing pressure. Its liquefied state means it takes up less space and can be stored and transported more easily.



Megawatt (MW)

Electrical unit of power equal to one million watts.

Megawatt hour (MWh)

A unit of measurement for electrical energy equal to one thousand kilowatt hours or one million watt hours.

Meter Point Administration Number (MPAN)

A 21-digit number for your electricity supply. You’ll see it displayed in a table or a row on your current electricity bill. It usually starts with the letter ‘S’.

Meter Point Reference (MPR)

A unique number for your gas supply that could be up to 10 digits long. You’ll find this number on your current gas bill.

Meter reading

Used to determine energy consumption and for issuing a bill for energy usage for a given period. Meter readings can be submitted online or by phone.

Meter Serial Number (MSN)

A unique number used to identify a meter. The MSN will be displayed on the front of most meters.

Micro business

You’re a micro business if you meet any one of the following conditions:

  • Use less than 100,000 kWh of electricity a year
  • Use less than 293,000 kWh of gas a year
  • Have fewer than 10 employees (or their full-time equivalent) and your yearly turnover, or yearly balance sheet, is not more than two million Euros

The consumption threshold applies to the fuel being supplied.

Micro generation

The small-scale production of energy via mini wind turbines, solar panels or mini generators.



National Grid

Owner and operator of the gas and electricity network in the UK.

Natural gas

Gas consisting of methane and ethane. Occurs naturally in the Earth's crust.

Non-Fossil Purchasing Agency (NFPA)

Created to enable Regional Electricity Companies (RECs) to meet renewable energy targets. It holds regular auctions for the purchase of renewable energy certificates, where energy has been sourced from renewable sources such as landfill gas, small-scale hydro and wind power.

Nuclear energy

Energy produced from a nuclear chain reaction of fissionable materials. Generated heat can be used to produce steam, drive turbines and generate electricity.




Gas removed from the National Transmission System (NTS) to meet customer demand.


The Office of Gas and Electricity Markets is the regulatory body for the electricity and gas industries. It protects consumer interests and ensures they get value and choice, by promoting competition and regulating monopolies.



Parent company

An affiliated company that exercises ultimate control over a business entity, either directly or indirectly. Centrica is the parent company of British Gas business.

Photocell switch

A switch which automatically turns lights on and off at dusk and dawn, meaning that no timer is needed. A photocell switch could improve energy efficiency when used in external lighting.

PP10 / PP11 certification

Certification to claim an exemption or a discount from the Climate Change Levy (CCL). PP10 / PP11 certification must be completed and sent to HM Revenue & Customs and the energy supplier.



Quoted company

A company whose shares can be bought or sold on a Stock Exchange.



Reactive power

The power returned to an electrical source by the reactive components of a circuit. Reactive power is measured in Volt-Amperes-Reactive (VAR). It’s considered ‘unproductive’ or ‘useless’ power because the energy is stored in the electrical circuit rather than being consumed. This energy is released and returned to the power source rather than being used to provide energy to appliances.

Recovered energy

Heat or energy which has been recovered from a process when it would otherwise have been lost. Setting up a power plant to recover lost heat could save wasted energy and cut costs.

Refrigeration plant

A cooling plant used for air conditioning, manufacturing processes and the storage of perishable goods. Configuring a refrigeration plant to run at its optimum efficiency can help save energy.

Renewable energy

Energy from natural sources which can be replaced as it’s used. Includes wind, solar and tidal energy. Using energy from renewable resources is considered to have less environmental impact and to help create a sustainable future for energy supplies.




A Shipperless supply is when there’s a gas meter on site but it hasn’t been registered correctly within the industry.

Smart meters

Meters which send readings automatically and remotely at regular intervals. Advantages of smart meters include that physical meter reads can be less frequent and that automatic readings can be used for more accurate, up-to-date billing. Frequent capture of energy consumption data can be used to analyse energy performance, compare energy usage patterns and predict future business needs using online management tools.

Sodium light

A light that works by using an internal sodium discharge, which emits a yellow-orange light. Low pressure sodium lamps are considered to be more energy efficient and less light polluting than conventional lighting. They are commonly used for night-time security and street lighting.

Solar power

Energy gained from the radiant energy of the sun. It can be converted into other forms of energy, such as heat and electricity.

Spray taps

Spray taps produce a wide spray of water, offering a greater coverage than conventional taps for easy and quick cleaning. When used for washing this can save water and energy.

Standing charge

A fixed cost paid in addition to usage charges for gas and electricity. Standing charges cover costs like meter reading, maintenance, connection to the energy network and, in the case of gas, emergency services.

Supply address

The address where energy is supplied and used. This may be different to the billing address where bills and invoices are sent.

Supply number

A unique reference number identifying the electricity meter at your property. It contains information which may be required by a new supplier e.g. the meter type. It’s usually shown on the front of your energy bill.


Sustainability is concerned with ensuring the long-term and responsible use of natural resources. This includes investing in renewable and alternative energy sources to secure future energy supplies, plus minimising impact on the environment from fossil-fuel resources.


The process of switching from one energy supplier to another.



Terawatt (TW)

Electrical unit of power equal to one thousand gigawatts.


The company owning the facilities (e.g. the pipeline) by which gas or liquefied natural gas (LNG) is physically transferred to your premises.


A rotary machine which is driven by water, steam, air or gas to generate energy.



Unit price

The price paid per unit of energy used (e.g. in kilowatt hours). The unit price includes costs such as transportation but excludes standing charges, government taxes such as VAT or the Climate Change Levy, or any other third party costs.

United Nations Framework Convention on Climate Change (UNFCCC)

An international treaty aimed at reducing global warming. The Kyoto Protocol of 1997, which is a legally binding agreement to reduce greenhouse gas emissions worldwide, is an addition to the UNFCCC.

Ultrasonic meter

A meter which measures gas flow using ultrasound pulses and continually checks for malfunctions, interference, tampering or service requirements.



Value Added Tax (VAT)

A government tax charged on most business-to-business and business-to-consumer transactions in the UK, including electricity and gas supplies.


A unit of electric potential. Electrical outlets in business premises are usually measured in volts.



Waste recycling

The collection of waste materials for re-use. This means that fewer new products and consumables need to be produced, saving raw materials and reducing energy consumption. British Gas business is set recycling targets by the Centrica Group.

Water power

A renewable energy source where energy is generated from a water source, such as hydro-electric, wave or tidal power.

Watt (W)

A unit of electrical measurement equal to one ampere under a pressure of one volt.

Watthour (Wh)

A unit of electrical measurement equal to one watt of power supplied to, or taken from, an electric circuit steadily for one hour.

Wind farm

A group of wind turbines (up to several hundred) for generating electrical energy. They are erected in areas of high and steady wind strength, both offshore and onshore.

Wind power

Energy generated by using wind to turn turbines and generate electricity. Wind energy is pollution-free and renewable. It is considered to be an economically viable and scaleable renewable energy source.

World Environment Day (WED)

Established by the United Nations and commemorated on 5th June every year. WED is used to stimulate worldwide awareness of environmental issues and to promote action.




An area within the interior space of a building to be cooled, heated, or ventilated, often using a thermostat to control temperature fluctuations. Zone isolation can help with energy efficiency as required conditions can be isolated to an individual zone.

Related help

Useful pages