The main international guidelines and standards on thermal comfort are:

·         International Standard ISO 7730. This standard is based on Fanger’s Predicted Mean Vote (PMV), which predicts the mean thermal sensation of a group of people, and the Predicted Percentage of people Dissatisfied with the environment (PPD).

·         ASHRAE 55 defines conditions that are being considered satisfactory for a specific percentage of users, including calculation methodologies for thermal comfort based on PMV/PPD

·         CEN 15251: Criteria for the indoor environment including thermal, indoor air quality, light and noise. The CEN standard defines minimum ventilation requirements, minimum and maximum indoor temperatures that can be used for energy calculation, assessment and certification. It is different than prescribed standards because it makes a difference between mechanically ventilated systems and naturally ventilated systems. For buildings without mechanical ventilation /cooling, alternative methods are proposed.

These guidelines and standards specify comfort in a broader sense that is easier to refer to and often stem from numerous more detailed and sophisticated guidelines and standards (normative references) such as:

·         ISO 7243, Hot Environments – Estimation of the heat stress on working man, based on the WBGT Index (wet bulb globe temperature)

·         ISO 7726, Ergonomics of the thermal environment — Instruments for measuring physical quantities

·         ISO 7933, Ergonomics of the thermal environment — Analytical determination and interpretation of heat stress using calculation of the predicted heat strain

·         ISO 8996, Ergonomics of the thermal environment — Determination of metabolic rate

·         ISO 9920, Ergonomics of the thermal environment — Estimation of the thermal insulation and evaporative resistance of a clothing ensemble

·         ISO 10551, Ergonomics of the thermal environment — Assessment of the influence of the thermal environment using subjective judgement scales

·         ISO 11399, Ergonomics of the thermal environment — Principles and application of relevant International Standards

·         ISO TR 11079, Ergonomics of the thermal environment — Analytical determination and interpretation of cold stress using calculation of the required clothing insulation (IREQ) and the assessment of local cooling effects

·         ISO 13731, Ergonomics of the thermal environment — Vocabulary and symbols

·         ISO/TS 13732-2, Ergonomics of the thermal environment — Methods for the assessment of human responses to contact with surfaces — Part 2: Human contact with surfaces at moderate temperature

·         ISO/TS 14415:, Ergonomics of the thermal environment — Application of International Standards to people with special requirements

·         Humphreys, M.A. and Nicol, J.F. (1998) Understanding the Adaptive Approach to Thermal Comfort, ASHRAE Transactions 104 (1) pp 991-1004

·         DeDear (2004), Thermal Comfort in Practice. Indoor Air Journal. Vol 14. Supplement 7, pp 32-39.

·         McCartney K.J and Nicol J.F. (2002) Developing an Adaptive Control Algorithm for Europe: Results of the SCATs Project. Energy and Buildings 34(6) pp 623-635

The general tendency on summer comfort should be to use the best available practical means, including alternative techniques, to control the indoor environment and provide stable indoor conditions in order to avoid discomfort, using the least possible energy.