Overview
EN ISO 10077-1:2017 (ISO 10077-1:2017, corrected 2020-02) is the CEN-endorsed part of the ISO 10077 series that establishes general methods for the calculation of thermal transmittance (U‑value) of windows, pedestrian doors and shutters. It specifies the inputs, calculation procedure, required outputs and reporting format for assemblies made of glazed and/or opaque panels fitted in frames, with or without shutters. The standard is part of the EPB (energy performance of buildings) set and supports EU energy performance requirements (EPBD).
Key topics and requirements
- Scope and output: Defines what assemblies are covered and the required output data (e.g., thermal transmittance values and related results to be reported).
- Calculation method: Describes the general calculation approach, applicable time intervals and the procedure for obtaining steady-state and quasi‑steady results.
- Input data:
- Geometrical characteristics (profiles, glazing areas, junctions)
- Thermal characteristics (material conductivities, glazing system properties)
- Linear thermal transmittance: Treatment of frame/glazing junctions and glazing bars is covered through linear transmittance (Ψ) considerations.
- Annexes (normative/informative): Provide templates, regional references, recommended surface resistances and detailed methods for air spaces, frames, glazing and combined window transmittance.
- Reporting: Clause 7 specifies the contents of the test/calculation report and required drawings and presentation of results.
- Interoperability: References and aligns with related documents (for example EN 12412-2, ISO 10292 and other ISO/TR entries) to ensure consistent input determination and EPB compatibility.
Practical applications and users
EN ISO 10077-1:2017 is used to:
- Calculate U‑values and linear thermal transmittances for product data sheets, energy simulations and compliance checks.
- Support product development and thermal optimization of frames, glazing and junctions.
- Provide the basis for certification, labelling and performance declarations required in building energy codes and certification schemes.
Typical users:
- Window and door manufacturers and R&D teams
- Energy assessors and building modelers
- Façade and thermal performance engineers
- Certification bodies, testing laboratories and regulatory authorities
- Architects and consultants specifying building components
Related standards
- ISO 10077 series (other parts covering detailed methods)
- EN 12412-2 (glazing thermal boundary conditions referenced)
- ISO 10292 (U-value determination references)
- ISO/TR 52022-2 (related technical reports)
Keywords: EN ISO 10077-1:2017, thermal transmittance, U-value, windows doors shutters, calculation method, thermal performance, EPBD, energy performance of buildings.