glossary
Welcome to our glossary of useful terms and expressions related to sustainability in the m&e sector.
You can search for definitions and explanations using our alphabetical links below or simply by scrolling through.
We hope you find these helpful and you will see as you navigate other pages on the site that each time a glossary term occurs there is a live link to its definition here.
Please contact the site editor Ewen Rose if there are other subjects you think we should include.
- Air leakage rate
- The uncontrolled movement of air in and out of a building, usually measured in cubic metres per hour per square metre of façade (see air pressure testing).
- Air permeability
- The rate of air flow passing through a known area under a prescribed air pressure.
- Air pressure testing
- Testing to measure the air leakage rate from a building, usually based on a standard 50 Pa reference pressure difference.
- Air source heat pumps
- Systems designed to extract low grade heat from the air surrounding a building and converting it into usable heat in the winter or, in reverse cycles, cooling in summer.
- Alternative Energy
- Energy derived from non-fossil fuel sources.
- Asset rating
- An energy efficiency rating given to new buildings based on their modelled energy use.
- Balance of System (BoS)
- Parts of the photovoltaic system other than the PV array, including: switches, controls, meters, power-conditioner and storage components if any.
- Biodegradable
- The ability of a substance to naturally degrade and return its nutrients to the earth.
- Biodegradable waste
- Waste that can be broken down by a natural process of decomposition with bacteria or other organisms.
- Biodiversity
- The variety of lifeforms that make up the ecosystems of the planet and how they interact. A system made up of a community of animals, plants and bacteria and its interrelated physical and chemical environment
- Biomass fuel
- Organic matter, such as wood, crops, or vegetation, that may be converted to an energy source. Common types of biomass fuel are wood chips and wood pellets.
- BREEAM
- Building Research Establishment Environmental Assessment Method – a way of assessing the environmental performance of buildings.
- Brown Water
- Water that has been used at least once, but that can be recycled without health risks and used in non-potable functions such as toilet flushing.
- Building Emissions Rate
- The level at which a building contributes to global warming and climate change by direct leakage of harmful gases or indirect generation of carbon dioxide from power generation.
- Carbon cap
- The limit set on a country, organisation or individual for carbon emission under any future carbon trading scheme.
- Carbon capture
- Removal of CO2 from fossil fuels during or after combustion, usually by extracting the CO2 from the flue gases.
- Carbon credit
- A credit or permit arising from a greenhouse gas emissions reduction scheme, such as emissions trading.
- Carbon dioxide
- A greenhouse gases produced during the combustion of fossil fuels. The gas is also produced by the combustion of non-fossil fuels and by plants and animals as part of respiration.
- Carbon emissions trading scheme
An EU-wide scheme whereby greenhouse gas emissions are controlled by setting a cap on total emissions and using a market-based approach via trading of emissions allowances.
- Carbon footprint
- A building's carbon footprint is the measure of the carbon emissions resulting from the use of that building, measured in units of carbon dioxide.
- Carbon Index rating (CI)
- A measure of the carbon dioxide emissions of a dwelling. Measured on a scale of zero to 10 with higher numbers corresponding to lower the emissions.
- Carbon neutral
- When applied to a building it means that the running of such a building is not responsible for any net carbon emissions. This is usually achieved through a combination of energy efficiency and the use of renewable energy but can also include offsetting the carbon emissions for example through tree planting offset schemes (see also zero carbon).
- Carbon storage
- The long-term storage of carbon or CO2 in the forests, soils, ocean, or underground in depleted oil and gas reservoirs, coal seams, and saline aquifers. Also referred to as engineered carbon sequestration.
- Carbon Tax
- A proposed tax based on the use of carbon by individuals and companies. Or see Climate Change Levy (CCL).
- Carbon Trust
- An independent not for profit company set up by the Government with support from business to encourage and promote the development of low carbon technologies. Key to this aim is its support for UK businesses in reducing carbon emissions through funding, supporting technological innovation and by encouraging more efficient working practices.
- CFC
- (Chlorofluorocarbon) Any of various halocarbon compounds consisting of carbon, hydrogen, chlorine, and fluorine, once used widely as aerosol propellants and refrigerants. Chlorofluorocarbons are believed to cause depletion of the atmospheric ozone layer.
- CheSS
- The Central Heating System Specification was produced in response to a request from the Heating Strategy Group of the Energy Efficiency Partnership for Homes. It gives current recommendations for good practice for the energy efficiency of domestic wet central heating systems.
- Climate change
- Since climates change as part of the natural cycle this phrase is usually taken to mean anthropogenic climate change, i.e. climate change caused by human activities such as burning fossil fuels and land use.
- Climate Change Levy (CCL)
- An additional tax on businesses added to their energy bills. The revenue raised by this tax is to be redistributed back to businesses by reducing the level of National Insurance contributions, so that the measure is described as 'revenue neutral'.
- Co-generation
- Another term for combined heat and power (see below) – used more commonly in some other European countries and the USA.
- Code for Sustainable Buildings (CSB)
- An evolving voluntary scheme being developed by government and industry. The aim of the CSB is the active promotion of more sustainable building practices.
- Code for Sustainable Homes
A system of sustainable building standards for homes, based on voluntary compliance, but expected to form the basis of the next revision to the Building Regulations.
- Combined Heat and Power (CHP)
- The simultaneous generation of usable heat and electrical power. CHP improves energy efficiency by using the waste heat from power generation and reducing the electrical transmission losses from the grid.
- Community heating
A term that is increasingly being used to describe district heating.
- Competent persons self-certification schemes
- Schemes to reduce the administrative burden of the Building Regulations by allowing self-certification of compliance by enterprises and individuals judged as competent.
- Contract energy management
Where an ESCO supplies energy and energy saving measures to the end user as a package. The end user pays the company for the service over a fixed period. The onus of achieving optimum efficiency is on the ESCO, though both will often agree to share financial benefits of energy savings.
- Daylighting
- The use of natural light, usually indirect, through windows, skylights, light shelves, and other techniques that minimize glare and heat. Daylighting in commercial buildings can help to improve worker productivity and a sense of wellbeing.
- Demand-side management (DSM)
- DSM is designed to help balance the amount of demand for energy with the capability of supply. It is particularly important with electricity because of the technical difficulties of storing it: DSM helps shift the loads between times of day or seasons to better utilise power resources. DSM also assists the reduction of overall demand for energy through, for example, improved energy efficient building services.
- District heating
- Heating provided from a local heating or energy centre via a network of pipes to serve a number of buildings in the locality. The size of the network can vary but in practice will usually be limited to a medium sized town or districts of a large city.
- EcoHomes
- The BREEAM method used for assessing residential buildings
- EcoHomesXB
- Developed by BRE in conjunction with the Housing Corporation, to allow stock holders of existing housing to assess and monitor the environmental performance of their stock.
- Emission standard
- The maximum amount of a pollutant that is allowed to be discharged from a polluting source such as a motor vehicle or chimney stack.
- Emissions
- A term used as shorthand to describe the emission of carbon dioxide into the atmosphere through combustion. Gases, liquids and solids that are discharged into the air, water or earth.
- Energy Efficiency Commitment (EEC)
- Formerly known as Energy Efficiency Standards of Performance (EESoP) is an obligation placed on all domestic energy suppliers to achieve a specified energy saving target through the installation of energy efficiency measures in homes across the UK. At least 50% of the benefits are focused on disadvantaged households. A similar scheme (Energy Efficiency Levy) operates in Northern Ireland.
- Energy from Waste
- Energy derived from waste, such as the use of methane collected from landfill sites and energy from waste incinerators.
- Energy performance of buildings directive (EPBD)
A European directive designed to improve the energy efficiency of buildings in Europe.
The requirements of the EPBD have been enshrined in the latest approved documents of Building Regulations Part F (Ventilation) and Part L (Conservation of fuel and power) for England and Wales.
- Energy Saving Trust (EST)
- An independent not-for-profit organisation set up and largely funded by the government to manage a number of programmes to improve energy efficiency, particularly in the domestic sector.
- Energy services company (ESCO)
- A company that supplies energy services to customers. Such services can include power and fuel supply, energy efficiency measures and energy audits.
- Enhanced Capital Allowance (ECA)
- Tax rebate scheme administered by the Carbon Trust allowing end users to offset 100% of the cost of low energy, water conservation and low carbon equipment against tax in the year it is purchased. Qualifying products are assessed and appear on the Trust's Energy Technology List.
- Environmental impact
- Any change to the environment, whether adverse or beneficial, wholly or partially resulting from an organisation's activities, products or services.
- F-Gas Regulations
- Regulations which come into force on 4 July 2007 and concern the use of fluorinated gases such as the HFC-based refrigerants. Operators of relevant systems will have a range of obligations including prompt leakage repair, leakage checking and record keeping and ensuring appropriately qualified personnel are used.
- F-Gases
- Gases containing fluorine used as refrigerants in air conditioning and subject to strict containment rules under the terms of the EU F-Gas Regulation from June 2007 (see F-Gas Regulation).
- Fossil fuel
- Any fuel that is derived from sediments of organic matter formed underground as part of geological processes. Common fossil fuels are coal, natural gas and petroleum.
- Fuel cells
- An electrochemical device (similar to a battery) that combines hydrogen and oxygen to produce electricity, heat and water. The source of hydrogen can be either pure hydrogen or a number of other fuels. Much of the development work is being carried out by the major motor manufacturers with future spin-off applications for use in buildings.
- Fuel poverty
- A household is defined to be fuel poor if more than 10% of its income needs to be spent to achieve a satisfactory indoor heating regime, after including other energy services such as cooking and lighting.
- Global warming
- The gradual increase in the earth's average temperature caused by the greenhouse effect.
- Green roofs
- Growing roof systems utilizing a specialised undercarriage for the waterproof membrane and excess water removal. Various types of vegetation are set into a special growing medium and help to replace displaced vegetation in the building footprint as well as greatly reducing the heat island effect. Green roofs can create pleasant gardens and help regulate stormwater flow.
- Greenhouse effect
- The heating that occurs when gases such as carbon dioxide trap heat escaping from the Earth and radiate it back to the surface; so-called because the gases are transparent to sunlight but not to heat and thus act like the glass in a greenhouse.
The means by which a proportion of the radiated heat from the Sun is trapped within the atmosphere by 'greenhouse gases'. - Greenhouse gas
Gases in the atmosphere that absorb heat radiated by the Earth and prevent this heat being lost into space. The main greenhouse gases are water vapour, methane, halocarbons (CFCs, HFCs, etc) and carbon dioxide.
- Greywater
- Wastewater from household baths, washing machines, and other sources (excluding human waste) that is recycled especially for use in gardening or for flushing toilets.
- Ground source heat pumps
- Systems that use refrigeration technology to convert low grade heat from the ground into usable energy that can heat a building. Ground source heat pumps typically attain a CoP (Coefficient of Performance) of between 2.5 and 4. Reversible heat pumps can be used to also provide cooling in the summer.
- Halocarbons
Compounds of halogens and carbon, such as chlorofluocarbons (CFCs).
Compounds of carbon combined with one or more of the elements called halogens (fluorine, chlorine, bromine, iodine, and astatine). Halocarbons containing fluorine, chlorine and bromine contribute to ozone depletion and to the enhanced greenhouse effect.
- Home Energy Efficiency Scheme (HEES)
- Equivalent of Warm Front for homes in Wales.
- Home Information Pack
- Required from June 2007 of all house sellers to provide potential buyers with additional information including an energy performance certificate.
- ISO 14001
- The internationally recognised standard for environmental management systems, accredited by the ISO (International Standards Organisation).
- Kyoto Protocol
- A United Nations international agreement to reduce emissions of carbon dioxide and other major greenhouse gases. The protocol now covers 160 countries.
- Landfill Tax
- A tax on the disposal of waste. It aims to encourage waste producers to produce less waste, recover more value from waste, for example through recycling or composting and to use more environmentally friendly methods of waste disposal.
- Largescale building integrated photovoltaics
- Systems where the photovoltaic panels replace conventional building materials such as roof tiles or facades.
- Life cycle cost
- The overall estimated cost for a particular system over the time period corresponding to the life of the system. It includes direct and indirect initial costs plus any periodic or continuing costs of operation and maintenance.
- Low and Zero Carbon (LZC) technologies
- Building services systems that are deemed to be either carbon neutral or very highly energy efficient so leading to low carbon emissions from power generation.
- Low Carbon Buildings Programme
- A grant scheme run by the Department of Trade and Industry offering up to £1million per project to subsidise the design, installation and use of low carbon technologies including ground source heat pumps, solar thermal water heating and wind energy. It provides grants for microgeneration technologies to householders, community organisations, schools, the public and not for profit sector and private businesses.
- Market Transformation Programme (MTP)
- Government programme that aims to bring forward products, systems and services that do less harm to the environment, using less energy, water and other resources. The MTP provides strategic support to a growing set of 'product' policies that aim to encourage resource efficiency through supply-chain measures such as reliable product information, raising minimum standards and encouraging best practice.
- Methane
- A compound of carbon and hydrogen (chemical formula CH4) and the main component of natural gas.
- Micro-CHP
- CHP on a very small scale, typically below 5kW electrical output, designed for use in homes and small commercial buildings.
- Micro-wind turbines
- Very small wind turbines (usually up to 1kW output) designed to provide electric power to a home or other local site for a variety of applications.
- Microgeneration
- Small electricity generating systems, typically ranging in size up to 50kWe output. They are installed close to the point of use, either in smaller businesses or homes. Such systems include CHP and renewables such as wind generation and photovoltaics.
- Montreal Protocol
- An agreement signed in Montreal in 1987 in which signatory nations consented to limit production and consumption of ozone-damaging chemicals.
- National Calculation Methodology (NCM)
- The procedure for demonstrating compliance with Building Regulations for buildings other than dwellings is by calculating the annual energy use for a proposed building and comparing it with the energy use of a comparable 'notional' building.
- Natural Ventilation
The process of bringing ventilation air into a building through open windows or other openings, due to wind pressure or temperature differences between the outdoor and indoor air, without the assistance of mechanical power.
The provision of ventilation in buildings without the use of fans and other forms of mechanical air movement.
- Operational rating
- A measure of the energy usage (and consequent carbon emissions) by a building compared to benchmarks for that type of building – usually based on at least 18 months of historical energy use data. (For new buildings see asset rating).
- Ozone
- An unstable gas formed by the interaction of sunlight with exhaust gases from motor vehicles and from industry and by the action of sunlight on nitrogen oxides and hydrocarbons where it is a primary component of smog.
- Passive solar energy
- Situating a building and using natural techniques to provide energy. Key techniques include daylighting, south-facing windows, natural shading and ventilation, and building materials that absorb heat from the sun and slowly release it.
- Peak oil
- The peak is the point at which oil demand will exceed supply currently estimated to occur in 15 years time. Some industry estimates suggest oil wells will run dry in 37 to 42 years time.
- Planning Policy Statement 1: Delivering Sustainable Development (PPS1)
- PPS1 sets out the government's overarching planning policies on the delivery of sustainable development through the planning system. This PPS replaces Planning Policy Guidance Note 1, General Policies and Principles, published in February 1997.
- Planning Policy Statement 22: Renewable energy (PPS22)
- This sets out the government's planning policies for renewable energy, which planning authorities should have regard to when preparing local development documents and when taking planning decisions.
- Polluter Pays Principle
The principle that the cost of controlling environmental pollution should be borne by the polluter rather than imposed on society as a whole.
- Rainwater Harvesting
- Techniques for recovering rainwater and diverting for use in systems such as toilet flushing, cooling and agriculture.
- Recovery
- The term encompassing the re-employment, reuse, recycling or regeneration of waste.
- Recycling
- The segregation, collection and reprocessing of waste into the same products or different ones.
- Renewable energy
- Renewable energy sources include solar power, geothermal energy, wind, wave and tide and hydro-electricity. They are so called because they do not depend on finite resources unlike fossil fuels.
- Renewable Obligation Certificates (ROCs)
Digital certificates that hold details of exactly how a unit of electricity was made, by whom and finally who bought and used it.
Energy companies are required to generate a minimum of 10% of their output from sustainable sources: if they have not managed to produce the required amount of green energy themselves they must buy ROCs on the open market to make up the shortfall.
- Renewables Obligation
- The obligation placed on licensed electricity suppliers to deliver a specified amount of their electricity from eligible renewable sources.
- RoHS
The Restriction of the Use of certain Hazardous Substances in electrical and electronic equipment Directive came into force in July 2006.
It bans new electrical and electronic equipment containing more than agreed levels of lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyl (PBB) and polybrominated diphenyl ether (PBDE) flame retardants.
- SEDBUK (Seasonal Efficiency of Domestic Boilers in the UK)
- The average annual efficiency achieved in typical domestic conditions, making reasonable assumptions about pattern of usage, climate, control, and other influences.
- Simplified Building Energy Model (SBEM)
- The calculation software developed by the BRE to enable building services designers to meet the requirements of Part L of the Building Regulations (2006).
- Sinks (also 'Carbon sinks')
- Plants absorbing more carbon dioxide from the atmosphere than they emit.
A mechanism which removes a greenhouse gas from the atmosphere e.g. forest planting - Site waste management plan (SWMP)
Provides a structure for waste delivery and disposal at all stages during a project, identifying who is responsible for resource management, types of waste generated, and how waste will be managed and measured.
- Solar heating (also solar thermal)
- Using the energy from the sun to provide hot water for a building. Solar panels usually come in two types: flat panels or vacuum tubes.
- Standard Assessment Procedure (SAP)
- Government endorsed energy rating system for homes, giving properties a score out of 120 whereby a score of 120 is the most efficient and 0 the least.
- Sustainable development
- Development that takes account of the available materials and natural resources and does not deplete them to the detriment of future development.
- Sustainable Development Commission
The Government's independent watchdog on sustainable development. The Commission's main role is to advocate sustainable development across all sectors in the UK, review progress towards it and build consensus on the actions needed if further progress is to be achieved.
- Sustainable urban drainage systems (SUDS)
- Drainage systems, which mimic as closely as possible the natural drainage of a site so as to minimise the impact of urban development on the flooding and pollution of waterways.
- Target Emissions Rate
- The preferred rate of greenhouse gas emissions from a proposed building or refurbishment project set by the project team and client at the outset of the design process.
- Thermal mass
- The heat storing capacity of the materials used in a building. Buildings composed mainly of bricks, blocks and concrete have a high thermal mass.
- Thermographic surveys
- Surveys using a thermographic camera to view temperature differences in the building's façade and roof showing the thermal performance of its insulation or lack thereof.
- Warm Deal
- Equivalent of Warm Front for homes in Scotland. (See Warm Front).
- Warm Front
- Government funded scheme targeting the Fuel Poor, to help cover the cost of basic energy efficiency measures, e.g. loft insulation, draught proofing, cavity wall insulation and heating controls.
- Warm Homes
- Equivalent of Warm Front for homes in Northern Ireland. (See Warm Front).
- Waste and Resource Action Programme (WRAP)
- A not for profit company created in 2000 as part of the Government's waste strategies across the United Kingdom. Its main objectives are to reduce waste and increase the uptake of recycling.
- Waste Electrical and Electronic Equipment Directive (WEEE)
- A European directive aimed a minimising the impact of electrical and electronic goods on the environment, by increasing re-use and recycling and reducing the amount of waste going to landfill. It seeks to achieve this by making producers responsible for financing the collection, treatment, and recovery of waste electrical equipment, and by obliging distributors to allow consumers to return their waste equipment free of charge.
- Water Technology List
- A list of products and systems developed by DEFRA and the Inland Revenue in partnership with Envirowise to encourage more efficient water use and improvements in water quality.
- White certificate
- A term used to describe any means of exchanging quantified energy savings resulting from the introduction of energy efficiency measures.
- Whole Life Costing (WLC)
- The true economic cost of a building to cover the costs of construction and maintenance over its lifetime.
- Wind Turbines
- Technologies for capturing energy from the wind via large propeller blades linked to energy batteries.
- Zero carbon building
- A building whose net carbon emissions from energy use over a year would be equivalent to zero either through total passive design or offsetting.