Citation: U´ scinowicz, P.; Bogdan, A. Directions of Modification of the Model of Perception of the Thermal Environment by Patients of Selected Hospital Wards. Energies 2022, 15, 3965. https://doi.org/10.3390/ en15113965 Academic Editors: Jan Kaczmarczyk, Joanna Ferdyn-Grygierek and Robert Sekret Received: 13 April 2022 Accepted: 17 May 2022 Published: 27 May 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). energies Article Directions of Modification of the Model of Perception of the Thermal Environment by Patients of Selected Hospital Wards Piotr U´ scinowicz and Anna Bogdan * Department of Air-Conditioning and Heating, Faculty of Building Services, Hydro and Environmental Engineering, Warsaw University of Technology, 00-664 Warsaw, Poland; uscinowicz.piotr@gmail.com * Correspondence: anna.bogdan@pw.edu.pl; Tel.: +48-22-234-7887 Abstract: Patients are different regarding their health conditions, illnesses and ailments, and mobility. These and other factors could affect their specific feelings about the thermal environment. Current methods of predicting thermal sensations were developed based on research on a group of healthy people. Therefore, the use of these methods with patients should be verified. This paper aimed to verify selected thermal comfort models in terms of their reliability to predict the average assessment of thermal conditions in the patient rooms and the percentage of dissatisfied patients. Thermal condition analyses were based on microclimate parameter measurements and extensive questionnaires among patients, done in parallel in the hospital’s patient rooms. The research was carried out in 23 hospitals located in the following provinces in Poland: (Warmi´ nsko-Mazurskie, Kujawsko- Pomorskie, Mazowieckie, Wielkopolskie, Lódzkie, ´ Swi˛ etokrzyskie, Lubelskie and Dolno´ sl ˛ askie). Overall, 890 patients from 14 different specialities participated in the research. Actual thermal sensations of patients differed from predictions obtained from selected thermal comfort models. A comparison of the actual thermal sensations with the PMV model indicates the shift of the comfort curve towards cooler rather than neutral conditions. A comparison of the same to the adaptive model predictions indicates that patients had a higher dissatisfaction rate and preferred cooler thermal conditions than predicted. Research findings show that normative models are not fully reliable in predicting patients’ thermal sensations. Keywords: thermal comfort; thermal environment; hospital; patients 1. Introduction The thermal environment is one of the internal environment elements that significantly affects the health, productivity, and efficiency of employees, which has been proven in many studies involving students or office workers [1–6]. Therefore, it can be assumed that in the case of sick rooms, it is crucial that the thermal environment conditions ensure the comfort of their users; however, all medical, technological, and sanitary-hygienic requirements must be met at the same time. In the literature, the human perception of the thermal environment is determined by three different methods, which can be described as physical, psychological, and physiological. The first is based on models of physical phenomena occurring at the boundary between humans and the external environment; the second uses the actual, subjective perception of the thermal environment by humans expressed, for example, in the so-called survey research; the third is based on measurements of physiological parameters such as body temperature. Normative models of thermal comfort [7,8] use a physical model that assumes that comfortable conditions in terms of thermal sensations are neutral and are equivalent to the state of thermal comfort, which occurs if the body exchanges a balance of heat with the external environment. The model [7] was developed based on PMV (Predictive Mean Vote) and PPD (Predicted Percent of Dissatisfied) indices, the determination of which requires registration of personal parameters (thermal insulation of clothing, metabolic output) and thermal environment parameters (air temperature, radiation temperature, relative humidity, and air velocity). Energies 2022, 15, 3965. https://doi.org/10.3390/en15113965 https://www.mdpi.com/journal/energies