ISO 23045:2008

Overview

ISO 23045:2008 - "Building environment design - Guidelines to assess energy efficiency of new buildings" provides practical guidance for assessing and improving the energy efficiency of new buildings. It complements ISO 16813 (building environment design principles) and ISO 16818 (energy-efficiency terminology). The standard is aimed at the whole design process, from conceptual stages to final design and commissioning, and applies specifically to space air‑conditioning equipment and heating plant, as well as associated systems such as lighting, domestic hot water and ventilation.

Key topics

• Scope and purpose
  • Guidelines to collect and provide required data at each design stage and to meet energy‑efficiency definitions prepared by building designers.
  • Applies to new buildings and assumes indoor comfort, freeze protection or IAQ requirements are met.
• Design process integration
  • Four design stages covered: conceptual, schematic, detailed and final design, with recommended inputs and outputs at each stage.
  • Emphasis on iterative, global approaches that consider interactions between building fabric and systems (HVAC, lighting, controls).
• Energy performance indicators
  • Methods to express energy efficiency for the building envelope, integrated building systems and secondary indicators to support assessment and labeling.
• Project data requirements
  • Comprehensive project information: location (latitude, longitude, elevation), site context (shading, orientation), building geometry, materiality, occupancy schedules and set‑points.
  • Hour‑by‑hour weather data and parameters recommended for annual assessments.
• Systems and loads
  • Systems to consider: heating, cooling, ventilation, lighting, domestic/service water heating and related controls.
  • Informative annexes provide guidance on thermal loads from occupants, lighting and equipment, and fuel energy values.
• Renewables and commissioning
  • Guidance on integrating renewable sources (solar, ground/water, wind) and on commissioning to ensure design targets are met.

Applications

• Useful to architects, building designers, HVAC engineers, energy modelers, energy assessors, consultants and owners involved in the design of new buildings.
• Supports:
  • Early stage energy target setting and labelling.
  • Preparation of input data for energy simulation and calculation tools.
  • Trade‑off analysis between passive measures and active systems.
  • Defining commissioning requirements and operational parameters to achieve intended energy performance.
• Applicable across projects seeking demonstrable energy performance, compliance with client or market labeling schemes, and integration of renewable energy strategies.

Related standards

• ISO 16813 - Building environment design: general principles for indoor environment.
• ISO 16818 - Building environment design: energy efficiency terminology.

Keywords: ISO 23045:2008, energy efficiency, building design, new buildings, HVAC, building envelope, energy performance indicators, renewable energy, commissioning.