## 3 Search Results and Classification
### Energy Performance  
In 41 studies, qualitative or quantitative aspects were reported, or statements were made regarding energy performance associated with the use, application, or implementation of industrialized construction systems. In this regard, 88% of the studies reporting on energy issues focused on prefabricated systems, 10% on modular systems, and only 2% provided data on traditional systems. It is important to note that five studies reported indicators on the percentage reduction of energy demand in housing projects, all of which were based on prefabricated systems, and the reduction is associated with energy savings in HVAC during the operational stage of the projects. In this case, the participation of countries in the background report is diverse, though with an emphasis on sectors from Europe, the United Kingdom, Italy, Portugal, Estonia, and Slovenia, among others, and there is less participation from the Americas and Asia, such as Chile and China, respectively. This is interesting, as, despite the diverse climates, the energy losses (thermal transmittance) of the analyzed construction systems tend to be similar. Below is a summary of the data reported by the authors, grouping the values of HVAC energy demand (Figure 5) and thermal transmittance of the analyzed construction element (Figure 6). For these categories, reference values required by the Passivhaus standard are shown, as it is one of the most stringent standards globally for transmittance and energy demand limits in housing [113]. Figure 5: Energy demand reduction of industrialized projects/solutions. In Figure 5, the energy demand reduction indicator varies between 20% and 90% (P67 and P45, respectively). It is important to note that for the latter case, the value is associated with a comparison to an unfavorable scenario for a house in Australia, without thermal insulation levels or energy efficiency requirements. The P24 construction system in a location in China achieved reduction rates of 17.7% for a severe cold climate and 77.1% for a temperate climate zone, suggesting the need to evaluate and consider the climate variable in proposing different materials for various types of construction systems. Apart from thermal transmittance, other variables should be optimized in the development of construction solutions. Study P33 from Italy specified the reduction of energy demand associated with heating (66%) and cooling (25%). Finally, study P50 determined a reduction of this indicator, with a value of 72%. Regarding thermal simulation on heating and cooling energy demand for a prefabricated project (P28) and a modular project (M13), values of 7.3 and 55 [kWh/m2/year] were obtained, respectively. For the prefabricated project, an envelope with low energy loss through conduction was considered based on the most stringent global criteria. For example, the windows had a thermal transmittance value of 0.73 [W/m2K]. This design adhered to zero-energy building criteria, considering an energy generation system, and the project's location was in China. The modular project utilized the WikiHouse system and conformed to net-zero energy building standards. In this case, the thermal envelope had comparable thermal transmittance values to the prefabricated project, but differences, such as double-glazed airtight windows, coupled with a cold climate in Chile, resulted in lower thermal performance than the first case. Although the geographical, climatic conditions, and HVAC systems differ, the operational energy demand results are comparable to the Passivhaus standard requirement, which has a maximum heating and cooling demand of 40 [kWh/m2/year]. Figure 6 shows the thermal transmittance values reported in 25 studies (compared to the Passivhaus standard), where the figures range from 0.1 [W/m2K] to 1.71 [W/m2K]. The lowest thermal transmittance value reported was from study M1, with a value of 0.10 [W/m2K], below the 0.15 [W/m2K] required for vertical elements in the Passivhaus standard.