1 Analysis of influencing factors of hotel indoor environment

**H1.** *Hotel air quality environment will have a positive impact on customers' subjective evaluation of the hotel's indoor environment.*

**H2.** *Hotel thermal environment will have a positive impact on customers' subjective evaluation of the hotel's indoor environment.*

**H3.** *Hotel acoustic environment will have a positive impact on the subjective evaluation of the hotel's indoor environment by customers.*

**H4.** *Hotel light environment will have a positive impact on customers' subjective evaluation of the hotel's indoor environment.*

**H5.** *Hotel non-light visual factor environment will have a positive impact on customers' subjective evaluation of the hotel's indoor environment.*

 2 Hotel modern simple style room type and indoor environment influencing factors

Many scholars have found that modern simple style achieves harmony in visual effects with simple and smooth lines, black, white, gray, and log colors, and other non-light visual factors; in terms of light environment factors such as space lighting, it combines overall and local lighting to satisfy the owner. Many studies have confirmed that non-light visual factors and light environment have a greater impact on customers' subjective ratings of the hotel's modern simple style room type C [39,40]. Based on the above research results and questionnaire survey results, the following research hypotheses are proposed:

**H6a.** *The hotel's light environment will have a positive impact on customers' subjective evaluation of the hotel's modern simple style room type.*

**H6b.** *The non-light visual factors of the hotel will have a positive impact on customers' subjective evaluation of the hotel's modern simple style room type.*

 3 Hotel British pastoral-style room type and indoor environment influencing factors Many studies have confirmed the important influence of non-light visual factors on customers' subjective evaluation of British pastoral-style room type [41], but few studies have studied the effect of light factors and air quality on the creation of a quiet, natural, pleasant, and relaxed atmosphere in British pastoral-style room type [42]. Through the analysis of KH Coder text of online evaluation, this study finds that the two factors of light and air quality have a great influence on the hotel's British pastoral-style room type, and then put forward the following assumptions:

**H7a.** *The light environment of the hotel will have a positive impact on customers' subjective evaluation of the hotel's British pastoral-style room type.*

**H7b.** *The air quality environment of the hotel will have a positive impact on customers' subjective evaluation of the hotel's British pastoral-style room type.*

 4 Hotel modern Japanese-style room type and indoor environmental influencing factors Studies have shown that modern Japanese-style room type uses a variety of retro furniture such as tatami and fan-shaped windows as decorations to highlight elegance and simplicity and go deep into the realm of Zen [43,44]. Therefore, the adjustment of factors such as room temperature and wind speed included in the thermal environment may be of important significance and the Japanese-style house type pays special attention to the use of "light", most of them are mainly warm-toned lights. So, putting forward the following assumptions:

**H8a.** *The light environment of the hotel will have a positive impact on customers' subjective evaluation of the hotel's modern Japanese-style room type.*

**H8b.** *The thermal environment of the hotel will have a positive impact on customers' subjective evaluation of the hotel's modern Japanese-style room type.*

 5 Hotel indoor environment and customer subjective evaluation

Based on the analysis of five influencing factors in IEQ theory, hypotheses are put forward:

**H9.** *The indoor environment of the hotel will have a positive impact on the overall customer subjective evaluation of the hotel.*

### *3.2. Data Analysis Method*

The framework of this research is shown in Figure 6 below. First, the reliability, validity, and factor analysis of the questionnaire were carried out. After testing the feasibility of factor analysis of the questionnaire, a demographic descriptive analysis of customer reviews was carried out. Then, principal component analysis (PCA) was carried out to determine the influence of various factors of the hotel's indoor environment on the subjective evaluation of tourists [43,45]. The study further applied factor analysis to eliminate the redundancy of correlated variables to reduce the number of available composite data [46]. To reveal the significant influence, significant difference, and joint distribution of different decoration styles on the subjective evaluation of the hotel, the study used SPSS to carry out single factor ANOVA, independent sample *t*-test, and further analysis of the data using the custom table to obtain in-depth data analysis conclusions and verify the hypothesis.

**Figure 6.** SPSS analysis frame diagram.

#### *3.3. Evaluation of the Reliability and Validity of the Scale*

#### (1) Reliability test

This study mainly used SPSS 25.0 to test the reliability of the scale. The larger the Cronbach's Alpha value, the greater the reliability of the scale. The coefficient should not be less than 0.6, and the questionnaire should be readjusted if it is below 0.6. The test results showed that the coefficient of the actual satisfaction scale was 0.962, and the coefficient of each sub-scale must be greater than 0.8, and most of them were greater than 0.9; then according to the criterion that the overall correlation coefficient (CITC) of the project proposed by the scholar Churchill should not be less than 0.5, the model was trusted. The results showed that the CITC values were all above 0.7, which meant that the scale of this research had a high degree of internal consistency and a small error value in the survey of hotel user groups, that is, the reliability of the questionnaire was high, and the reliability was strong.

(2) Validity test

The KMO test and Bartlett's test of sphericity were used to analyze whether factor analysis was possible. The results of the KMO test showed that the value of KMO was 0.958. At the same time, the results of the Bartlett sphericity test showed that the significant *p* value was 0.000 \*\*\*, infinitely close to 0, and the level was significant, rejecting the null hypothesis, indicating that this questionnaire had validity, and there was the correlation between variables, which was suitable for factor analysis. The factor analysis results showed that there was at least one value greater than 0.4 in the loading values of all the variables in the row, so the variables were reasonable and did not need to be deleted.

(3) Test the convergent validity of the model

Confirmatory factor analysis is performed on the convergent validity of the measurement model. Further evaluation of the structural model can only be performed if the fit of the measurement model meets acceptable standards. The test results showed that the standardized factor loadings of all dimensions were above 0.7 and were significant; the compositional reliability CR values were all higher than 0.8, and the average variance extraction (AVE value) was greater than 0.5. Therefore, the model had good convergent validity.

#### *3.4. Demographic Description of the Sample*

First, study participants were screened according to the inclusion criteria; second, questionnaires were collected through screening questions, 856 questionnaires were initially collected, and after excluding outliers, a total of 710 valid questionnaires were used for data analysis. Among them, the majority of respondents were women, accounting for 62%; the age group accounted for the largest proportion of the 18–29-year-old group (93%) because the way such as giving gifts was more attractive to young women; most respondents had a bachelor's degree (88%). For profession, middle school students (84%) accounted for the majority; 77% of all valid participants had a monthly income of less than 3000; this study was mainly based on college students. To be realistic, there are no barriers to the survey respondents, so there are some non-college student groups of respondents. The specific results can be seen in the following Figure 7:

Additional relevant demographic information (Figure 8) was measured to further understand respondents. Respondents mostly chose the modern simple style (60.6%), followed by the British pastoral style (22.7%) and the modern Japanese style (16.7%); most respondents traveled with friends (40.8%); leisure travel was the reason why most respondents stayed in hotels (79.3%).

**Figure 8.** Chart of other population data indicators.
