## 5 Results and Discussion
### Energy Consumption, Cost of Energy, and Carbon Emission Evaluations  
In Figure 11, the monthly energy costs for heating are presented. We can see that the reference building had almost double the energy consumption compared to the case A building, with the highest energy consumption reaching 42 MWh for the reference building and 22 MWh for case A. Additionally, we can notice a larger difference between scenarios regarding monthly energy consumption for the reference building. The reference building under the reference control scenario presented increased energy consumption compared to the PRBC scenarios during January, February and March. The case A building under the reference control presented increased energy consumption compared to the PRBC scenarios only during January. It is evident that implementing DR in the case A building led to increased energy consumption, while implementing DR in the reference building can lead to decreased energy consumption, which probably comes with decreased thermal comfort levels. Regarding energy costs (Figure 12), we can see that the cost PRBC presented the best overall behavior for the reference building. Specifically, we noticed that during every month, except February and December, the monthly energy costs of the Cost PRBC were lower compared to the other scenarios. In February, the CO2 PRBC gave the best results regarding cost, which was mainly attributed to the lower energy consumption of CO2 PRBC during February. In December, the reference control resulted in the lowest costs, which was again attributed to the lower energy consumption of reference scenario. Regarding the case A building, the Cost PRBC proved to be the most efficient scenario during February and March; CO2 PRBC was the most efficient during January; and the reference control was the most efficient for the rest of the months. This level of difference between the case A  
Figure 10: Flexibility index in terms of CO2 eq. building and the reference one, where the CO\({}_{2}\) PRBC was the most cost efficient, can be attributed to the increased energy consumption during DR for the case A building. Finally, regarding CO\({}_{2\text{eq}}\) emissions (Figure 13), the CO\({}_{2}\) PRBC, as expected, seemed to decrease emissions during most months compared to the other two control scenarios. Figure 11: Monthly electricity consumption for heating. Figure 12: Monthly energy costs for heating. Specifically for the reference building, the CO\({}_{2}\) PRBC presented the lowest emissions during January and especially February; the cost PRBC gave the greatest results for March, April and November; and the reference control produced the best results for December. The results for the case A building indicate that there were decreased CO\({}_{2\text{eq}}\) emissions during CO\({}_{2}\) PRBC in January and February and the reference control was rated as the most efficient one for the rest of the months. Table 4 shows the annual results for both buildings under the different control scenarios. For the reference building, the energy consumption decreased by 1.7% under the Cost PRBC and by 0.6% under the CO\({}_{2}\) PRBC. Both DR scenarios led to decreased costs and emissions compared to the reference control. Specifically, the costs were reduced by 1.9% under the CO\({}_{2}\) PRBC and by 3.6% under the Cost PRBC; emissions were reduced by 3.3% under the cost PRBC and by 3.5% under the CO\({}_{2}\) PRBC. We can notice that a small energy consumption reduction was converted to higher costs and emission reduction, indicating a shifting of consumption to times with a lower cost of energy and emissions intensity. Still, we can notice that DR comes with sacrificing thermal comfort, with increased thermal discomfort hours under both PRBCs (15.4-23.1%). A similar study was conducted by [PERSON] et al. in a residential building in Norway [21]. The implemented CO\({}_{2}\) PRBC led to an increase in CO\({}_{2\text{eq}}\) emissions when implemented in the heat pump system.