ISO 7730-2025 PDF

Full title and description

ISO 7730:2025 — Ergonomics of the thermal environment — Analytical determination and interpretation of thermal comfort using calculation of the PMV and PPD indices and local thermal comfort criteria. This edition defines analytical methods for predicting mean thermal sensation and the percentage of people likely to be dissatisfied (PMV/PPD), and sets criteria for both whole-body and local thermal comfort in moderate indoor environments where thermal comfort is desirable.

Abstract

This standard specifies a procedure to evaluate general thermal comfort and the degree of thermal dissatisfaction in moderately varying indoor environments. It describes calculation and interpretation of the Predicted Mean Vote (PMV) and Predicted Percentage of Dissatisfied (PPD) indices, and provides local thermal comfort criteria (for vertical air temperature differences, radiant asymmetry, local cooling from air movement, and floor temperature). The standard is intended for the design and assessment of workplaces and other indoor spaces where thermal comfort is required.

General information

• Status: Published (International Standard).
• Publication date: 2025-09 (Edition 4, 2025).
• Publisher: International Organization for Standardization (ISO).
• ICS / categories: 13.180 (Ergonomics of the thermal environment).
• Edition / version: Edition 4 (2025).
• Number of pages: 35.

Scope

Applies to healthy men and women exposed to indoor environments where thermal comfort is desirable and where moderate deviations from neutral conditions may occur. The standard gives analytical methods to determine PMV and PPD and sets acceptability criteria for whole-body and local thermal comfort in the design of new environments or assessment of existing ones. Although developed for work environments, it is applicable to a wide range of indoor spaces.

Key topics and requirements

• Definitions and calculation methods for PMV (Predicted Mean Vote) and PPD (Predicted Percentage of Dissatisfied).
• Local thermal comfort criteria addressing vertical air temperature differences, radiant asymmetry, floor surface temperature, and local air movement (draft risk).
• Comfort categories (A/B/C/… or numerical bands) linking PMV ranges to maximum allowable PPD (for example Category II commonly uses PMV ≈ ±0.5 with PPD ≤ 10%).
• Required input parameters for PMV/PPD calculations: air temperature, mean radiant temperature, air velocity, relative humidity, metabolic rate (activity), clothing insulation and (where relevant) work performed.
• Guidance on acceptable operative temperature bands, spatial and temporal variability, and measurement practice consistent with ISO 7726 instrumentation recommendations.
• Notes on interpretation: PMV is on a –3 to +3 scale (cold to hot) and PPD is a derived non‑linear function of PMV that predicts expected dissatisfied percentage in a large group.

Typical use and users

Used by building designers, HVAC engineers, indoor environmental quality consultants, occupational health and safety professionals, ergonomists, researchers, and standards bodies to: assess or specify thermal comfort performance of indoor spaces; size and control HVAC systems; support energy/comfort tradeoffs; and validate simulation or measurement-based comfort studies. It is applied in offices, schools, healthcare facilities, industrial workplaces and other indoor environments.

Related standards

Commonly used alongside ISO 7726 (Instruments for measuring and monitoring the physical quantities of the thermal environment), ISO 9920 (estimation of clothing thermal insulation and evaporative resistance), and regional standards such as ASHRAE 55 and relevant EN adaptations (e.g., EN ISO versions). ISO 7726:2025 provides complementary requirements on instrumentation and measurement methods referenced in ISO 7730.

Keywords

thermal comfort; PMV; PPD; predicted mean vote; predicted percentage of dissatisfied; local thermal comfort; operative temperature; ergonomics; indoor environment; HVAC; ISO 7730:2025.

FAQ

Q: What is this standard?

A: ISO 7730:2025 is an international standard that defines analytical methods to predict and interpret thermal comfort using PMV and PPD indices and sets criteria for whole‑body and local thermal comfort in moderate indoor environments.

Q: What does it cover?

A: It covers the calculation and interpretation of PMV and PPD, local comfort criteria (vertical air temperature gradients, radiant asymmetry, draft, floor temperature), acceptable comfort categories and guidance on applying these criteria for design and assessment of indoor environments.

Q: Who typically uses it?

A: HVAC and building services engineers, ergonomists, indoor environmental quality consultants, occupational health professionals, researchers, and standards committees use ISO 7730 to set or verify comfort targets and to support simulation or measurement-based assessments.

Q: Is it current or superseded?

A: The 2005 edition of ISO 7730 was withdrawn and superseded by ISO 7730:2025 (Edition 4). The 2025 edition is the current published international standard.

Q: Is it part of a series?

A: Yes — ISO 7730 is part of the ergonomics/thermal environment set of standards (ICS 13.180) and is commonly used together with ISO 7726 (instrumentation), ISO 9920 (clothing insulation), and related national and regional standards (for example ASHRAE 55 and EN adaptations).

Q: What are the key keywords?

A: PMV, PPD, thermal comfort, operative temperature, local discomfort, ergonomic design, HVAC performance, ISO 7730:2025.