## 3 Results and Discussion  
### The Effect of Exterior Wall Envelope Insulation on Thermal Comfort  
The hourly values of indoor air temperature, humidity and internal surface temperature for all rooms were obtained by simulations with DeST software, and the values from the simulations were imported into the CBE [25] thermal comfort calculation tool to obtain the hourly values of room PMV. The APMV under a typical meteorological year of the living room and study is calculated by Equation (1), as shown in Figures 2 and 3. Due to the large number of experimental simulation results, this paper presents the room thermal comfort in box-line diagram (5 days/box) for the heating season. Figure 2 shows from 15 November to 30 November, the APMV mean values in the living room of the original and standard building were predicted to be \(-0.86\) (with daily mean values from \(-0.95\) to \(-0.62\)) and \(-0.78\) (with daily mean values from \(-0.86\) to \(-0.52\)). From 1 December to 28 February, with the outside temperature gradually decreased, the APMV values in both buildings decreased, the average APMV of the original building was maintained around \(-0.87\) and the average APMV of the retrofitted regulated building was maintained at \(-0.8\). Figure 3 shows the modelled APMV for the study room, which more intuitively demonstrate the effect of building envelope retrofit on indoor thermal comfort. The modelled mean APMV for the original building study was \(-0.9\) (with daily mean values from \(-1.02\) to \(-0.67\)), the modelled mean APMV for the regulated building was \(-0.76\) (with daily mean values from \(-0.82\) to \(-0.46\)). During the nighttime, the occupants in sleeping state were assumed to be 0.7 met and the 4.5 clo [26], respectively. The hourly values of indoor air temperature, humidity and inner surface temperature in the bedroom at night are obtained by DeST software, the SPMV values for the sleeping condition were calculated by Equation (2) and shown in Figures 4 and 5. Figure 3: PMV in the study room during heating season: **(a)** original building and **(b)** standard building. Figure 2: PMV in the living room during heating season: **(a)** original building and **(b)** standard building. Figure 4 shows the SPMV daily mean values of the original building's south-facing bedroom varies from \(-0.04\) to \(1.17\) with seasonal mean value of \(0.42\) during the heating season. While the SPMV daily mean values of the standard building south-facing bedroom varies from \(0.47\) to \(1.07\), and the seasonal mean value during the heating season is \(0.63\). Figure 5 shows the SPMV daily mean values of the original building's north-facing bedroom varies from \(-0.09\) to \(0.95\) with seasonal mean value of \(0.34\) during the heating season. While the SPMV daily mean values of the standard building south-facing bedroom varies from \(0.47\) to \(1.07\), and the seasonal mean value during the heating season is \(0.63\), which has the same trend and similar values as the south-facing bedroom. In this part, we simulated the APMV of the original building and the standard building with the envelope insulation retrofit at the same indoor temperature, and compares the simulation results. The simulation results show that even though the indoor air temperature  
Figure 4: SPMV in the heating season for south-facing bedrooms: (**a**) original building and (**b**) standard building. Figure 5: SPMV for north-facing bedroom heating season: (**a**) original building and (**b**) standard building. reaches the thermal expectation temperature of indoor residents, the indoor APMV is still at a low level, indicating that the indoor temperature is not an important indicator of indoor thermal comfort. Additionally, this result is consistent with the field survey, in which the residents thought that the indoor temperature had been adjusted to a high level, but the indoor cold feeling was obvious. At the same time, it was found that the reason for the large difference in room APMV at the same temperature was the internal surface temperature.