## 5 Conclusions  
This study investigated the interaction between sound and thermal comfort in hospital wards in China's heating region. An objective investigation was carried out, where participants evaluated sound comfort, thermal comfort, and overall comfort. Meanwhile, a subjective measurement of the sound pressure level, temperature, and humidity were carried out.  
For overall comfort, the effects of sound and temperature are stronger than the effect of humidity, while the effects of sound and temperature are almost equal. For thermal comfort, the temperature in the wards was satisfactory, with a measured value of 26-30 \({}^{\circ}\)C, and highly acceptable at 27-29 \({}^{\circ}\)C. The patients had a preference for temperatures that are higher than the standard value in ISO 7730 and ASHRAE 55-2004. The relative humidity was unsatisfactory, and heating exacerbates this phenomenon. For acoustic comfort, the LAeq in the wards was satisfactory, with a measured value of 45-65 dB, and highly acceptable at 45-55 dB. There was a positive correlation between the acoustic comfort evaluation of the speech of staff, shouting, crying, and pager sounds, with shouting and crying being the most relevant.  
The influence of thermal factors on sound evaluation showed that a low temperature has little effect on the evaluation of acoustic comfort, whereas for any type or volume of sounds, the higher the temperature, the more negative the evaluation. Irrespective of the type of sound source, when the humidity was low, the effect on acoustic comfort was the most obvious, but when the humidity was  
Figure 8: The percentage of comfort evaluation for different durations of stay. (**a**) Thermal, (**b**) acoustic.  
Figure 7: The percentage of comfort evaluation for different ages. (**a**) Thermal, (**b**) acoustic.  
medium or high, it was non-significant. In terms of shouting, crying, and pager sounds, the effects of temperature and humidity were more obvious, and high temperature and low humidity have a negative influence. With a medium temperature and humidity, the effect of improving acoustic comfort got better.  
The similarities and differences in the evaluations of the sound and thermal influences also showed that there is an analogous trend in patients' environment comfort and preferences because of their high correlation coefficient. A satisfactory thermal environment can improve the evaluation of acoustic comfort, while an unsatisfactory thermal environment has the opposite effect.  
Notwithstanding its limitation, this study clearly indicates that the special climatic environment in cold regions of China can cause changes in patient satisfaction. The building environments that affect patients' satisfaction include the thermal and acoustic environment. It should be noted that this study was focused specifically on patients in the cold region of China, and this specificity could affect the generalization of their findings of other patients. The geographical limitations of this study should be considered in interpreting these findings. Other regions or countries may produce different results. The three influencing factors selected in this study are dominated by thermal and acoustic comfort. Because of the dominant role of vision and air quality, future research can add lighting factors and indoor air quality as variables to study the influence of these additional factors on patient satisfaction.  
Conceptualization, Y.W., Q.M., L.L., and J.M.; Methodology, Y.W., Q.M., L.L., and J.M.; Investigation, Y.W.; Formal Analysis, Y.W.; Data Curation, L.L.; Writing-Original Draft Preparation, Y.W.; Writing-Review and Editing, Y.W., Q.M., L.L., and J.M.; Visualization, Y.W.; Supervision, Q.M. and J.M.; Project Administration, Q.M. and J.M.; Funding Acquisition, Y.W. and Q.M.  
This research was supported by the National Natural Science Foundation of China (NSFC) (51808160, 51878210).  
The authors declare no conflict of interest.