Overview
EN ISO 15927-1:2003 - Hygrothermal performance of buildings specifies procedures for the calculation and presentation of monthly means of single meteorological elements used to assess building thermal and moisture performance. Part 1 defines how to derive and report monthly (and multi‑year) averages and related statistical quantities for climate variables such as air temperature, atmospheric humidity, wind speed, precipitation, solar radiation and longwave (sky) radiation. Instrumentation and observation methods are not included (these follow WMO guidance). Numerical data should be sourced from the appropriate national meteorological service.
Key topics and technical requirements
- Scope of variables: air temperature, humidity (vapour pressure, mixing ratio, relative humidity), wind speed and direction, precipitation totals, solar irradiance/irradiation (global, direct, diffuse, reflected), and longwave atmospheric irradiance.
- Data sources: recommendations to obtain numerical values from national meteorological services; observation methods are the responsibility of the WMO.
- Periods and reporting: procedures support single-month calculations or aggregation across corresponding months in multi‑year datasets; the reporting period (specified year or multi‑year range) must be stated with results.
- Statistical measures: calculation of monthly means/totals and standard deviations (for daily means/totals about monthly or annual means); guidance on expression of results and relevant units.
- Solar and longwave guidance: informative annexes provide methods for splitting global solar irradiance into direct and diffuse components, and for estimating longwave sky irradiances and sky temperature.
- Definitions & symbols: standardized terms (e.g., mixing ratio, saturated vapour pressure, reference wind speed) and units for consistent reporting.
Applications and who uses it
EN ISO 15927-1 is used by:
- Building designers and HVAC engineers - to provide climate input data for hygrothermal and energy simulations.
- Energy modelers and researchers - for consistent monthly climate datasets used in building performance assessment and comparative studies.
- Standards bodies and consultants - to harmonize reporting of climatic parameters in design documentation, compliance checks and product assessments.
- Meteorological offices and data providers - as a format and methodological reference when supplying monthly climate statistics for building applications.
Practical uses include preparing climate inputs for hygrothermal simulations, establishing monthly boundary conditions for building energy models, and generating climate tables for design guidance (cooling/heating loads, moisture risk assessment).
Related standards
EN ISO 15927 is a multi‑part series for hygrothermal performance:
- Part 2 - data for design cooling loads and overheating risk
- Part 3 - driving rain index from hourly wind and rain
- Part 4 - data for annual heating and cooling energy assessment
- Part 5 - winter external design temperatures and wind data
- Part 6 - accumulated temperature differences for heating energy assessment
Keywords: EN ISO 15927-1:2003, hygrothermal performance, climatic data, monthly means, meteorological variables, solar irradiance, longwave radiation, building design, thermal performance, moisture performance.
