Air Source Heating: Technical Terms Explained

So, you already know that air source heating is better for the environment, your bank balance, and giving your home a more controlled heating system. But, what does all the technical jargon mean? Don’t worry, because we have you covered with our glossary of all the technical terms.

Air Source Heat Pump

Similar to how an air conditioning unit works, just the other way around, an air source heat pump changes cold air into warm air. The heat pump is located outside of a property or building and absorbs the air, compresses it, increases the temperature, and then transfers the warm air through to radiators and underfloor heating.

Air Quality Emissions Certificate

Biomass boilers must obtain an air quality emissions certificate to be used within the Renewable Heat Incentive (RHI) scheme. The boiler must be tested by an accredited laboratory to receive the certificate.

Biomass Boiler

Instead of using gas like a conventional boiler, a biomass boiler produces heat and hot water by burning sustainable wood pellets.

Biomass Suppliers List

A list of all registered suppliers of biomass wood fuel who meet the Renewable Heat Incentive requirements.

Carbon Footprint

The amount of greenhouse gases emitted into the atmosphere produced by human actions. Usually expressed in tons of carbon dioxide (CO2).


Found in the middle of the heat pump system, a compressor circulates the refrigerant found in the air between heat exchanger coils. The coils then allow the refrigerant to evaporate and absorb heat to then be released to heat a property or building.

Defrost Cycle

Occasionally a layer of ice may appear on top of the heat pump unit and an automatic defrost cycle will remove it.

Domestic Renewable Heat Incentive

A UK Government scheme to encourage homeowners, self-builders, and private or social landlords to use renewable heat technologies and to be paid for their usage.

Economy 7 Tariff

Also known as a differential tariff, economy 7 is a plan by your electricity supplier to help you use less and pay less for your electricity consumption. The normal rate for electricity is applied during the day, however, cheaper rates are applied for seven hours during the evening.

Economy 10 Tariff

The economy 10 tariff is the same concept as the economy 7 tariff. However, cheaper rates are applied for ten hours instead of seven.

Energy Performance Certificate (EPC)

A certificate which outlines the energy efficiency of a property and recommends solutions of how the property’s energy efficiency could be improved.

Energy Saving Trust (EST)

An independent non-profit organisation that runs various programmes and schemes to help improve energy efficiency.

Fossil Fuels

Fuels that are used from natural processes such as coal, oil, and natural gases.

Geothermal Energy

The heat from the earth which is green and sustainable.

Ground Source Heat Pump

Similar to how an air source pump works, a ground pump extracts heat from the ground to be compressed and transferred into a property.

Microgeneration Certification Scheme (MCS) Certificate

A quality assurance scheme which has been put in place to ensure products and installation companies are adhering to guidelines at a high standard. This certificate is a requirement to be eligible for the RHI scheme.

Non-Domestic Renewable Heat Incentive

The same scheme as the Domestic Renewable Heat Incentive but targeted to help businesses, public sector, and non-profit organisations.


The Office of Gas and Electricity Markets – the Government regulator for all gas and electricity markets in Great Britain.

Renewable Energy Association (REA)

A representative of all renewable energy producers who help to promote the use of all types of renewable energy within the UK.

Renewable Energy Consumer Code (RECC)

Set up by the REA, the code is a sign that a company has agreed to abide by the standards set out in the consumer code. It is to help guarantee that consumers experience high quality energy systems for their properties.


A fluid used in the heat pump cycle.

Renewable Energy

Energy that is generated and produced from natural sources such as sunlight, wind, water, and geothermal heat.

Underfloor Heating

The heated floor surface radiates heat throughout space to generate warmth.

We hope the explanation of a few terms has helped you with your understanding of air source heating. If you have any questions check out our blog, which has more information on all things eco-friendly and air source heating related – you can also call us on 0330 021 8128.

Feb 27 2019