air-conditioning system — a combination of the components required to provide a form of indoor air treatment, by which temperature is controlled or can be lowered 15.

boiler — the combined boiler body-burner unit, designed to transmit to fluids the heat released from burning 16.

building — a roofed construction having walls, for which energy is used to condition the indoor climate 1.

building element — a technical building system or an element of the building envelope 9.

building envelope — the integrated elements of a building which separate its interior from the outdoor environment 7.

building unit — a section, floor or apartment within a building which is designed or altered to be used separately 8.

cogeneration — simultaneous generation in one process of thermal energy and electrical and/or mechanical energy 13.

cost-optimal level — the energy performance level which leads to the lowest cost during the estimated economic lifecycle, where: the lowest cost is determined taking into account energy-related investment costs, maintenance and operating costs (including energy costs and savings, the category of building concerned, earnings from energy produced), where applicable, and disposal costs, where applicable; and the estimated economic lifecycle is determined by each Member State. It refers to the remaining estimated economic lifecycle of a building where energy performance requirements are set for the building as a whole, or to the estimated economic lifecycle of a building element where energy performance requirements are set for building elements. The cost-optimal level shall lie within the range of performance levels where the cost benefit analysis calculated over the estimated economic lifecycle is positive 14.

district cooling — the distribution of thermal energy in the form of steam, hot water or chilled liquids, from a central source of production through a network to multiple buildings or sites, for the use of space or process heating or cooling 19.

effective rated output — the maximum calorific output, expressed in kW, specified and guaranteed by the manufacturer as being deliverable during continuous operation while complying with the useful efficiency indicated by the manufacturer 17.

energy from renewable sources — energy from renewable non-fossil sources, namely wind, solar, aerothermal, geothermal, hydrothermal and ocean energy, hydropower, biomass, landfill gas, sewage treatment plant gas and biogases 6.

energy performance certificate — a certificate recognised by a Member State or by a legal person designated by it, which indicates the energy performance of a building or building unit, calculated according to a methodology adopted in accordance with Article 3 12.

energy performance of a building — the calculated or measured amount of energy needed to meet the energy demand associated with a typical use of the building, which includes, inter alia, energy used for heating, cooling, ventilation, hot water and lighting 4.

European standard — a standard adopted by the European Committee for Standardisation, the European Committee for Electrotechnical Standardisation or the European Telecommunications Standards Institute and made available for public use 11.

heat pump — a machine, a device or installation that transfers heat from natural surroundings such as air, water or ground to buildings or industrial applications by reversing the natural flow of heat such that it flows from a lower to a higher temperature. For reversible heat pumps, it may also move heat from the building to the natural surroundings 18.

major renovation — the renovation of a building where: the total cost of the renovation relating to the building envelope or the technical building systems is higher than 25 % of the value of the building, excluding the value of the land upon which the building is situated; or more than 25 % of the surface of the building envelope undergoes renovation; Member States may choose to apply option (a) or (b) 10.

nearly zero-energy building — a building that has a very high energy performance, as determined in accordance with Annex I. The nearly zero or very low amount of energy required should be covered to a very significant extent by energy from renewable sources, including energy from renewable sources produced on-site or nearby 2.

primary energy — energy from renewable and non-renewable sources which has not undergone any conversion or transformation process 5.

technical building system — technical equipment for the heating, cooling, ventilation, hot water, lighting or for a combination thereof, of a building or building unit 3.