Overview
ISO 15928-5:2013 - Houses - Description of performance - Part 5: Operating energy defines a standardized method for describing the operating energy performance of houses. It specifies user needs, performance descriptions and evaluation processes for energy used and energy generated by a house. The standard applies to dwellings that are standalone or linked horizontally (not vertically), and supports assessment of individual houses or groups of linked houses where services may be shared. ISO 15928-5 is a descriptive framework - it does not set performance levels or provide design methods.
Key topics and technical requirements
- Objective: Provide a consistent way to describe operating energy performance in terms of providing suitable indoor conditions and fulfilling user energy needs over the house’s design life.
- User needs: Addresses thermal comfort, functionality, efficient energy use and consideration of renewable vs non‑renewable energy.
- Performance description: Expresses probability of meeting indoor thermal comfort, illumination, hot water availability, built‑in appliance operation, and acceptable energy consumption.
- Parameters for description:
- External climate: Geographical location (climate data and procedures such as those in ISO 13790 may be used).
- Indoor conditions: specified ranges of temperature, humidity and ventilation.
- User functional requirements: hot water quantity/temperature, lighting levels, other functional parameters, and occupant numbers/characteristics.
- Energy used: quantified in megajoules (MJ) or kilowatt‑hours (kWh) per appropriate unit (time, area, capita).
- Energy generated: type and ratio of on‑site generated energy to total consumption (e.g., solar PV/thermal).
- Evaluation methods: Analysis, testing, service experience, or a combination. Evaluations should provide adequate documentation and consider linked‑house scenarios.
- Specific evaluation guidance:
- Space conditioning energy: follow ISO 13790.
- Hot water: account for distribution losses.
- Lighting: consider natural lighting utilization, interior surface finishes, and artificial lighting systems.
- Energy generation: evaluate types and amounts produced.
Applications and users
ISO 15928-5 is intended for:
- Manufacturers, developers and system suppliers describing house performance or prefabricated housing sub‑systems.
- Regulators and standards bodies seeking a neutral, WTO‑compatible framework to specify performance requirements.
- Design teams and energy assessors performing comparative evaluations, certification or product declarations where a standardized performance description is needed.
- Buyers and specifiers who require clear, comparable operating energy information.
Related standards
- ISO 13790 - Energy performance of buildings - Calculation of energy use for space heating and cooling (referenced for indoor condition evaluations)
- ISO 23045 - Guidelines to assess energy efficiency of new buildings (evaluation methods)
- ISO 16818 and ISO 6707-1 - terminology and general building terms used throughout this part
Keywords: ISO 15928-5, operating energy, houses, energy performance, performance description, indoor conditions, hot water, lighting, renewable energy, kWh, MJ.