All unit costs and calculations correct at the time of publication.

Home energy jargon: A-Z

If you want to take better control of your home energy – whether by switching to a better tariff or investing in renewables – unfortunately you’re likely to need to master at least some of the mountains of jargon.

Here’s a run-down of some common terminology you might come across.

Agile Tariffs

A new type of home energy tariff that enables you to shift your electricity use to when it’s cheapest and can even pay you to use electricity. 

Big six

The name for the UK's six largest power suppliers: British Gas, EDF, E.ON, Npower, Scottish Power and SSE.

Bill shock

The term given to the sudden increase in electricity bills faced by new owners of electric cars (however, it's more than offset by savings made at the pump). 

Biomass heating systems

An alternative type of home heating system, these burn organic material - such as logs, pellets or chips - in a stove or boiler to provide heat and hot water. Biomass heating systems aren’t entirely green, as they do produce pollutants. But they are more efficient than open fires and other burnt fuels.

Combi boiler

A combi, or combination, boiler is so-called because it does two things: heats water and also provides heating. This type of boiler doesn’t need a hot water cylinder and may be more efficient than a regular boiler, which does have a cylinder.

Condensing boiler

A more efficient type of boiler, which makes better use of the heat generated from burning fuels, such as gas or oil. All gas-fired boilers fitted after the 1st April 2005, and all oil-fired boilers fitted after 1st April 2007 are condensing boilers.

Dual fuel tariffs

A tariff, designed for convenience, where you get gas and electricity from the same energy supplier and receive one bill.


Eco-anxiety or climate anxiety is the name given to the increased anxiety or despair that people feel about the environment and their perceived helplessness to make a difference.

Energy Company Obligation (ECO)

An incentive to support energy efficiency improvements in low income and vulnerable households. The obligation is on the largest energy suppliers to support household install energy improvements.

Energy efficiency 

In the home, energy efficiency means using less energy to achieve the same result, whether it’s keeping your house warm or using your computer. There are various steps you can take, for example, by insulating a house, less energy is used in heating and cooling. This will lead to financial savings and help the environment.

Energy Performance Certificate (EPC) 

This is a compulsory report for all home sellers or landlords. The four-page report contains information about a property’s energy use and costs, as well as recommendations about how to go about reducing them. It gives the building a rating from A to G, with A the most energy efficient and G the least.

Energy Switch Guarantee

Switching to a cheaper tariff is one of the simplest ways of saving money on your home energy bills. The Energy Switch Guarantee is a commitment that promises a speedy and safe switch from one energy provider to another.

Estimated bills

Energy suppliers estimate your energy usage and then claim monthly or quarterly amounts based on this. This can result in you making under or over payments. 

Exit fee

If you’re on a fixed term energy contract and want to leave early, you may be charged an ‘exit fee’. If you’re in the last 49 days of your deal, you don’t have to pay this fee.

Export tariffs

This is a new type of tariff to tie in with the introduction of the Smart Export Guarantee (see below). 

Fixed or capped energy tariffs

An energy tariff where the unit cost of your electricity or gas is fixed for a certain time period, usually a year, protecting you from price increases. But you won’t benefit if energy prices are cut.

Green Deal

This started as a government-backed scheme but was unsuccessful. It has evolved into a system of loads offered by the Green Deal Finance Company to help households and landlords invest in renewable energy or energy efficient products. 

Green energy 

Energy from a renewable energy source – one that won’t run out – such as wind, hydro and solar.

'Green' energy tariffs

An increasing number of green suppliers offer tariffs providing renewable electricity. Some companies only buy renewable electricity, and so all their customers are on a green tariff.

Heat pumps 

Heat pumps use existing warmth in the air or ground to warm up radiators, underfloor heating systems, or water in your home.  Air source heat pumps (ASHPs) absorb heat from the outside air and ground source heat pumps (GSHPs) extract natural heat from the ground. 

Home batteries

A battery, or energy-storage system, which stores the electricity captured by solar panels during the day, for use at another time. The result can be lower fuel bills and reduced carbon emissions, as you’re not as reliant on electricity from the grid. 

Hydro power

Hydro or hydroelectric power is the energy derived from flowing water, using a turbine. This is a renewable energy source.

Kilowatt hour (kWh) 

A measure of how much energy you’re using, which you’ll see on gas and electricity bills. One kilowatt hour is 1 kilowatt (1,000 watts) of electricity used for one hour. 


An LED, or light-emitting diode, is a more environmentally friendly alternative to traditional lighting. They’re long-lasting and more durable than other bulbs, as they aren’t made of glass and don’t have a filament.


Loop is an energy-saving assistant that shows you how you use electricity and then helps you to make smart decisions about using less. You save money on your electricity and you help to save the planet.

Micro-CHP boilers

Micro combined heat and power (micro-CHP) is a technology that generates heat and electricity at the same time and is used in new, more efficient boilers. 


The government regulator for gas and electricity suppliers. It acts in the interests of consumers.


A standard of highly energy-efficient home building characterised by features such as very high levels of insulation, a mechanical ventilation system and airtight building fabric.

Phantom load

Some devices constantly sap energy in the background, when you’re not using them or have even switched them off. This is the ‘Phantom Load’. This includes appliances such as a freezer, which must be kept on continuously, as well as devices that are left on standby and can be turned off.

Prepayment tariffs

Households on prepayment meters pay in advance for gas and electricity using prepay tokens, cards or a key. 

Renewable energy

Energy generated from natural sources that can’t be used up, including wind, hydro and solar.

Renewable Heat Incentive

A government payment intended to encourage uptake of renewable heat systems. It pays out for every unit of energy that your home generates using a renewable heating system like a heat pump, wood boiler or solar water heating. 

Smart Export Guarantee (SEG) 

An incentive providing payments to homes and businesses that install new solar panels - and other forms of renewable energy generation with a capacity up to 5MW - for exporting electricity to the grid. It effectively replaces Feed-in Tariffs (FIT), an old government subsidy scheme, which closed to new entrants from March 2019.

Smart meters

A new generation of gas and electricity meter, which are intended to bring an end to manual meter readings, while helping people take control of their energy use and adopt energy-saving habits.

Smart plugs

Internet-connected devices that enable you to switch appliances on and off remotely or place them on a timer.

Smart thermostats

These connect your heating to the internet, so you can control it remotely with your smartphone.

Solar panels

Solar panels convert solar energy from the sun into electricity, even on cloudy days. Photovoltaic, or PV, cells are grouped together in panels which are usually mounted on your roof. 

Solar thermal

A renewable energy source, using panels on your roof and heat from the sun to heat water, which is stored in a hot water cylinder. 

Standard or variable tariffs

With these tariffs, the price of your energy will rise or fall with the market. This is your supplier’s default (normally expensive) option.

Standby saver

These devices cut power to appliances when they go into standby mode.

Time-of-use electricity tariffs 

These tariffs offer cheaper energy during specified off-peak, low demand times of day. 

The two most common time of use tariffs are: Economy 7 tariffs, which provide cheaper electricity for seven hours each day, usually between midnight and 7am; and Economy 10, which offer ten hours of ‘off-peak’ energy.

Vehicle to Grid

An evolving technology enabling households to automatically charge an electric car when demand on the national grid is low, and then sell the energy back to the grid when demand is high. So, you save money, and also help to reduce pressure on the grid.

Virtual power plants

An interlinked system, where solar panels, batteries and electric vehicles are all linked together to cut energy bills, reduce carbon emissions, and help manage the electricity system more efficiently. 

Wind power

Wind turbines harness the power of the wind and generate renewable electricity. Domestic-sized wind turbines are generally either free standing or mounted on roofs.

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With Loop, you can find out how you use electricity, then make smart decisions about using less - click here to find out more. We have a risk-free, no-quibble, money-back guarantee as standard, so what's to lose...apart from some £££ from your bills and some weight from your carbon footprint?

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