## 6 Conclusions and Future Research  
Resilient and sustainable planning, construction and management of the built environment are priorities in European energy and environmental policy. The integrated management of the carbon neutrality aim for buildings is a concern that primarily concentrates on energy-intensive operations like heating and cooling. Since distribution grid bottlenecks are anticipated in the near future, reducing energy use during peak load hours is one of the most crucial control objectives in the Greek context. Utilizing buildings' energy flexibility and HVAC systems should also increase a building's and its inhabitants' resilience to climate change and unpredictable conditions [32]. Greek electricity has a relatively high price compared to the other European countries, with prices even reaching 900 \(\upmu\)C/MWh in 2022. However, the Greece electricity market has modest levels of CO\({}_{\text{2 eq}}\) intensity compared to the rest of the European countries, with levels lower than 500 kgCO\({}_{\text{2 eq}}\)/MWh. In this paper, two types of PRBC were used to examine the demand response for heating a typical Greek office building. Two cases of a building with different thermal characteristics were evaluated. The actual heating system of the building consists of gas-fired boilers. In order to implement DR, we chose to replace the boilers with a VSHP during the modelling process. In this study, a detailed model of the building and the heating system was realized in TRNSYS. By using hourly spot prices and the hourly CO\({}_{\text{2 eq}}\) intensity of the electricity mix as an input, the two PRBC techniques aimed to lower heating energy costs and CO\({}_{\text{2 eq}}\) emissions, respectively. A third control scenario was implemented in an effort to quantify energy storage in the thermal mass of the building and assess its storage efficiency. The price-based PRBC led to both decreased heating costs (\(-3.6\%\)) and CO\({}_{\text{2 eq}}\) emissions (\(-3.3\%\)) when implemented in the reference building. The implementation of the cost PRBC in the case A building led to increased costs of energy (0.7%) and CO\({}_{\text{2 eq}}\) emissions (1.1%) compared to the reference control, which were mainly attributed to the large increase in energy consumption (4.9%) compared to the reference control. The CO\({}_{\text{2}}\) PRBC led to reduced emissions compared to the reference control for both the reference building (\(-3.5\%\)) and the case A building (\(-0.2\%\)). Again, the slight reduction of CO\({}_{\text{2 eq}}\) emissions for the case A building was attributed to the large increase in energy consumption. The carbon-based PRBC also led to a reduction of costs (\(-1.9\%\)) compared to the reference control for the reference building. Generally, both PRBC controls managed to achieve the goal of their application when implemented in the reference building. When implemented in the case A building, the increase in the energy consumption due to DR left no room for reducing costs and carbon emissions. Future research includes the implementation of model-predictive control and the investigation of its possible benefits, especially in the case A building where PRBC was found to fail. Other aspects worth investigating is the testing of DR controls on various heat emission systems to further clarify the role of thermal mass in the energy flexibility provided and further assess the impact of demand response to indoor environment quality [33].