*2.3. Indoor Temperature Analysis Methodology*

The third comparison analysis studies the impact of using the two weather datasets (*on-site* and *third-party* weather files) for the building's indoor temperature. In order to allow the temperature comparison, the energy used by each model is fixed. In other words, both simulations with *on-site* and *third-party* weather data use the exact same energy; however, due to the differences in the weather parameters, the indoor temperature is different. The methodology consists of performing the first simulation with the *on-site* weather file to obtain the baseline energy demand for each thermal zone of the model. This baseline energy demand is then injected into the model using an EnergyPlus script for an HVAC machine that distributes that energy in each thermal zone. Then, the model is simulated for both the *on-site* and *third-party* weather files. The results of the building temperature—unifying thermal zone temperature, weighing it with respect to its volume—of these two last simulations are compared to analyze the impact on the indoor temperature conditions.

In this case, two quantitative indexes (mean absolute error *MAE* (8) and root-mean-squared error *RMSE* (9)) and a qualitative index (*R*<sup>2</sup> (7)) are used to quantify the variation in the shape of the temperature curves.

$$MAE = \frac{1}{n} \sum\_{i=1}^{n} |y\_i - \hat{y}\_i| \tag{8}$$

$$RMSE = \left[\frac{1}{n}\sum\_{i=1}^{n} (y\_i - \hat{y}\_i)^2\right]^{\frac{1}{2}}.\tag{9}$$

The *MAE* and *RMSE* indexes are used to determine the average variation of the indoor temperature when using the different weather files in the simulations [61]. Both measure the average magnitude of the variation in the units of the variable of interest and are indifferent to the direction of the differences, overcoming cancellation errors. However, *RMSE* gives a relatively high weight to large deviations [62–64]. *RMSE* will always be greater than or equal to *MAE* (due to its quadratic nature); thus, the greater the difference between *MAE* and *RMSE*, the greater the variance between the individual dispersions on the sample. In this case, the three metrics are calculated for the hourly criteria.
