3. Methodology

There are many ways to measure carbon emissions from buildings, with the most common being the carbon emissions factor (CEF) method. Many similar studies have applied the CEF method because of its clear measurement principles and simple data acquisition [56,57]. This method has been used for the study of carbon emissions from highway construction in Southwest China [58], the study of carbon emissions from high-rise residential buildings in Tehran during the construction stage [59], and the study of carbon emissions from precast concrete panels during the materialization stage [45]. Since prefabricated decoration has a high degree of standardization and accuracy, the CEF method can quickly estimate a project’s carbon emissions. Moreover, many studies used this method to measure the material, prefabricated component, or building carbon emissions, which provided CEF data and research ideas for this study. Given the effectiveness of the methodology, this study adopted the CEF method for calculations and, based on that method, developed a framework for the carbon emissions measurement model for prefabricated decoration, as shown in Figure 1. The framework includes four steps that can realize the carbon emissions measurement of prefabricated decoration across its life cycle.

The first step was to divide prefabricated decoration into five stages from a lifecycle perspective: production, transportation, on-site installation, operation, and dismantling. Then, based on field research, the process of prefabricated decoration was specifically analyzed, and the calculation boundaries of each stage were determined. The second step was to select the CEF applicable to this study by analyzing national norms, reports of professional research institutes, international carbon emissions databases, and scholars’ research data, with timeliness, region, and applicability as evaluation criteria. The third step were to obtain consumption data on energy, labor, materials, and equipment in the relevant stages through research on prefabricated decoration construction sites, construction companies, and material suppliers. The fourth step was to calculate prefabricated decoration carbon emissions by substituting construction data and the corresponding CEF into the equations.

Figure 1. Carbon emissions measurement framework for prefabricated decoration.

3.1. Carbon Emission Calculation Boundaries

Currently, most scholars apply LCA theory to analyze the sources of carbon emissions from buildings and assess the impact of buildings on the surrounding environment through calculations [60]. From a life cycle perspective, prefabricated constructions can be divided into six stages: building material production, component preparation, component transportation, on-site construction, operation and maintenance, and dismantling and recycling [61]. Zhang and Wang divided the life cycle of a building into three parts: the materialization stage, the operation stage, and the disposal stage, of which the materialization stage includes production, transportation, and on-site installation [62]. In this study, to account for the characteristics of prefabricated decoration, the life cycle of prefabricated decorations is divided into five stages: production, transportation, on-site installation, operation, and dismantling. Figure 2 shows the specific carbon emissions measurement boundaries.

Figure 2. Measurement boundary for prefabricated decoration carbon emissions.

3.2. Carbon Emissions Factors

Many scholars, authoritative organizations, and institutions worldwide have compiled various databases on CEF after field research, which have specific reference values [63]. However, due to differences in experimental purposes, testing techniques, geographical areas, and measurement times, no standardized CEF database has been formed so far. Therefore, accounting accuracy, consistency of sources, and geographical affiliation should be followed to ensure the selection’s validity. In this study, the CEF involved in calculating carbon emissions from prefabricated decoration includes four aspects: transportation, decoration materials, electricity, and labor.

The mode of transportation is selected based on the size, shape, quality, and delivery value of the goods being transported, and the specific means of transportation are also different. Table 1 shows the CEF for the transportation modes used in the case study project. For some decoration materials used in smaller quantities, the proportion of their carbon emissions is small, and the overall impact on the assessment results is negligible. Therefore, consideration can be given to selecting a few primary decoration materials used in larger quantities for accounting. Table 2 shows the CEF for the decoration materials of the case study project. The data are derived from the Standard for Calculating Carbon Emissions from Buildings (GB/T 51366-2019) [64] and the Standard for Calculating Carbon Emissions from Building Decoration (T/CBDA 69-2023) [65].

Table 1. CEF for different modes of transportation.

Table 2. Main materials required for prefabricated decoration and their carbon emissions.

3.3. Carbon Emissions Equations

According to the boundary of carbon emissions calculation, prefabricated decoration can be divided into five stages: production, transportation, on-site installation, operation, and dismantling. Finally, the summary calculation is carried out to obtain the whole life cycle carbon emissions. The total carbon emissions of prefabricated decorations are calculated as follows:

where is the total carbon emissions of the prefabricated decoration, is the carbon emissions in the production stage, is the carbon emissions in the transportation stage, is the carbon emissions in the on-site installation stage, is the carbon emissions in the operation stage, and is the carbon emissions in the dismantling stage.

• Production stage

Carbon emissions at the production stage are only considered for producing raw materials, including those directly used in prefabricated decoration and those used in making component parts. The equation is as follows:

where is the consumption of the i-th building material (t), and is the CEF corresponding to the i-th building material (kgCO₂e/unit quantity of material).

• Transportation stage

Carbon emissions in the transportation stage are directly proportional to material consumption, material capacity, and average transportation distance. It is closely related to the choice of transportation mode and the CEF per unit weight. The calculation formula is as follows:

where is the consumption of the i-th primary building material, is the average transportation distance of the i-th building material (km), and is the CEF per unit weight of the i-th building material (kgCO₂e/t·km) for the transportation mode of the i-th building material.

• On-site installation stage

The on-site installation stage needs to consider the carbon emissions generated during the construction of prefabricated decorations due to construction machinery and workers. The equations are as follows:

_Where is the carbon emissions generated by the x-th inventory in the prefabricated decoration construction stage (x = 1, 2, 3,…, m), is the volume of work for the y-th quantity within the x-th inventory in the prefabricated decoration construction stage, and is the carbon emissions generated per unit for the y-th quantity within the x-th inventory in the prefabricated decoration construction stage (y = 1, 2, 3,…, n).

• Operation stage

The calculation of carbon emissions during the operation stage of prefabricated decoration refers to the building’s operation in terms of the heating, ventilation, and air-conditioning (HVAC) system, the domestic hot water system, and the lighting system. This study does not consider the carbon emissions generated by the daily operation of other commonly used household appliances and equipment. The equation is as follows:

where is the carbon emissions from the operation of the HVAC system (kgCO₂), is the carbon emissions from the operation of the domestic hot water system (kgCO₂), and is the carbon emissions from the operation of the lighting system (kgCO₂). The equations are as follows:

where is the annual energy consumption of HVAC per unit area (kWh/m²·a), is the annual energy consumption of domestic hot water per unit area (kWh/m²·a), is the annual energy consumption of lighting per unit area (kWh/m²·a), EF is the electricity CEF (kgCO₂/kWh), and N is the building design life (a).

• Dismantling stage

Data on the dismantling stage are not readily available. Carbon emissions during the dismantling stage include those generated during the dismantling of the building, the transportation of the demolition materials, and the recycling process. According to Li et al. (2022), carbon emissions from dismantling can be estimated at 90% of the construction stage, and the transportation of demolished items can be regarded as the inverse process of the material transportation stage, so that carbon emissions generated by the transportation of demolition items can be calculated at 90% of the material transportation stage [61]. Since carbon emissions from recycling are complex with very little data available, they are not considered in the dismantling stage of this study. The equation is therefore as follows:

This is a life-cycle carbon accounting model for prefabricated decoration. When using this model, it is only necessary to record the actual data that occurred in the project and set it into the corresponding equation for calculation. In the following, the model is utilized with examples from the case study project.

4. Case Study

4.1. Overview of the Case Study Project

The Jinhua Haiyue Huafu project is in Jiangbei District, Jinhua City, Zhejiang Province. It is a large-scale residential project with a total construction area of about 213,700 m², consisting of 21 small and high-rise buildings of 15–26 floors. The project applies advanced prefabricated decoration technology, starting at the national strategic level. It adopts green and environmentally friendly decorative materials, forming an industrialized and standardized carbon-reducing pathway. To further study the carbon emissions pattern of prefabricated decoration, the 22# residential building of the Haiyue Huafu project was selected for empirical analysis. The surface area of the case study building is 8409.61 m², and the total building area for energy-saving calculation is 8260.18 m².

The selection of this case study building was based on its representativeness and typicality, while the size and characteristics of the project were considered necessary to draw stronger conclusions. The in-depth analysis of this case study project will help to understand prefabricated decoration’s carbon emissions in actual projects more comprehensively and provide quantitative data on the patterns of carbon emissions from buildings adopting prefabricated decoration. Furthermore, findings from the case study are expected to provide the construction industry with information for managing carbon emissions, helping with environmental sustainability, and promoting the practice of green construction.

4.2. Prefabricated Decoration Techniques for the Case Study Building

The case study building was completed with prefabricated decoration for the floor and bathroom systems. In the floor system, prefabricated wood flooring is used in the bedrooms, from bottom to top: bottom adjustable bracket, oriented strand board base layer, underfloor heating module and underfloor heating coil, and solid wood composite flooring. In the dining room, prefabricated floor tiles are used, and the floor tiles can be used according to the design requirements to achieve the design effect. Prefabricated decoration flooring systems do not require wet concrete work and can therefore increase the speed of construction. The dry and wet areas of the case study building each use a separate aluminum honeycomb composite monolithic chassis, and the walls use aluminum honeycomb composite tile monolithic wall panels. The wall panels are connected to the monolithic chassis to form an overall waterproofing system. Compared with the traditional bathroom, aluminum honeycomb material has a better flame retardant and heat retardant effect, and its surface is treated with epoxy fluorocarbon, which has strong corrosion and aging resistance and can effectively avoid wall cracking.

In addition, the case study building adopts a prefabricated decoration integration design process at the design stage, synchronizing the interior design with the architectural design, thus avoiding the conflict between civil engineering structure and interior decoration and avoiding wall trenching for the construction of water and electricity pipelines at the decoration stage. The building can form a prefabricated decoration information platform at the design stage, including the code, model, material, manufacturer, and other information about the parts and components. Through this platform, transportation, on-site installation, and post-maintenance organization can be carried out efficiently. Prefabricated decoration breaks the traditional thinking of decoration and opens the assembly industry chain of integrated parts, unified design, lean manufacturing, assembly construction, and lightweight maintenance. The carbon emissions of the case study building using prefabricated decoration techniques can be quantified, and the carbon emissions characteristics and reduction potential of prefabricated decoration can be further analyzed based on the calculation results.

4.3. Case Study: Building Carbon Emission Results

4.3.1. Carbon Emissions from Decoration Materials Production

Based on Equation (2) and the construction data from the case study building, the total carbon emissions of the prefabricated decoration of the residential building at the production stage can be calculated. From the calculation process, the carbon emissions at the production stage are directly related to the consumption of materials and the corresponding CEF. Figure 3 illustrates the percentage of carbon emissions generated by different material consumption in the production stage of the case study residential building’s prefabricated decoration.

Figure 3. Material share of carbon emissions at the prefabricated decoration production stage.

To better compare the carbon emissions of prefabricated and traditional decoration, it is necessary to calculate the carbon emissions of adopting traditional decoration in the production stage. Using Equation (2) and the empirical data collected from the project, the estimated carbon emissions of the case study residential building using traditional decoration methods during the production stage can be calculated. The calculation results are shown in Table 3.

Table 3. Main materials required for traditional decoration and their carbon emissions.

The main materials used in traditional decoration differ from the prefabricated decoration in terms of type and consumption, contributing to the different carbon emissions produced by the two types of decoration during the production stage. Figure 4 shows the percentage of carbon emissions generated by different material consumption during the production stage of the case study residential building using traditional decoration.

Figure 4. Material share of carbon emissions at the traditional decoration production stage.

4.3.2. Carbon Emissions from Transportation

This section calculates the carbon emissions generated by the energy consumed to transport traditional and prefabricated decoration materials between the plant and the worksite. In this project, the materials are transported by road, and the transportation distance is set to 500 km according to the source information. Based on Equation (3), the carbon emissions of traditional and prefabricated decoration at the transportation stage are as shown in Tables 4 and 5.

Table 4. Carbon emissions during the transportation stage of traditional decoration.

Table 5. Carbon emissions during the transportation stage of prepabricated decoration.

4.3.3. Carbon Emissions from On-Site Installations

Carbon emissions sources during the on-site installation include labor and mechanical equipment. The prefabricated decoration on-site installation took a total of 56 days to complete, with a total of 25 professional workers on-site. Carbon emissions from labor activities are calculated using 1.11 kgCO₂/person-day as the CEF. Since the prefabricated decoration parts and components are pre-produced in the plant and transported directly for installation at the site, which reduces on-site cutting and other operations, the machinery used at the project’s on-site installation stage mainly consists of electric drills, hoists, and temporary lighting equipment. The average daily power consumption during the on-site installation is 51.78 kWh. The carbon emissions from the on-site installation stage are shown in Table 6.

Table 6. Carbon emissions during the on-site installation stage of prefabricated decoration.

The carbon emissions distribution of the prefabricated decoration materialization stage can be derived from the carbon emissions calculation results of the production, transportation, and on-site installation stages, as shown in Figure 5.

Figure 5. Carbon emissions distribution at the materialization stage.

4.3.4. Operational Carbon Emissions

The project adopts prefabricated decoration technology, and the operation stage is calculated according to the comprehensive index of building energy savings provided in the Energy Saving Design Standard for Residential Buildings in Zhejiang Province (DB33/1015-2021). The building calculation conditions are as follows: (i) The indoor temperature of the case study residential building is 16 °C in winter and 26 °C in summer; (ii) The heating calculation period is from December 15 to February 15 of the following year, and the air-conditioning calculation period is from June 15 to September 1 [66].

The split air conditioner of the case study building achieves level 1 energy efficiency, the Integrated Part Load Value (IPLV) value of the multi-connected system reaches more than 6.6, and the energy-saving standard requirement is 4.4. The energy-saving and emission-reduction analysis of the HVAC system is shown in Table 7.

Table 7. Calculation of emission reduction for HVAC systems.

Each household in the project uses an air-source heat pump to provide domestic hot water, with an energy efficiency of 4.4. Compared to a conventional electric water heater, the emission reduction analysis is shown in Table 8. The project’s lighting system emissions reduction analysis is shown in Table 9.

Table 8. Calculation of domestic hot water system emissions reduction.

Table 9. Calculation of emission reduction for lighting systems.

Combining the results of the emission reduction analysis of the HVAC, lighting systems, and domestic hot water, the carbon emissions at the project’s operation stage compared to a traditional building are shown in Figure 6.

Figure 6. Comparison of carbon emissions at operation stage.

The reduction in carbon emissions during the operation phase in the case study of prefabricated decoration compared to traditional decoration can be attributed to the adoption of energy-efficient HVAC systems, the use of air-source heat pumps for domestic hot water, efficient lighting systems, and an integrated design approach that focuses on sustainability. The prefabricated decoration technology, along with the choice of materials and construction methods, contributes to overall energy savings and reduced carbon emissions during the building’s operational life. These measures collectively result in a lower environmental impact during the operation stage compared to traditional decoration methods.

4.3.5. Dismantling Carbon Emissions

The demolition process typically requires workers to break down, dismantle, and clean up a building or component using hand tools and mechanical equipment, and both the worker activities and the operation of the mechanical equipment generate carbon emissions. Transportation of demolition items from the demolition site to a disposal or recycling site requires transportation, and the energy consumed during transportation results in carbon emissions. The waste disposal process may involve landfilling, incineration, recycling, or other methods, some of which may generate carbon emissions.

Since the project has not yet entered the dismantling stage, it is impractical to obtain the carbon emissions based on the actual situation, so the carbon emissions at this stage are measured by using the calculated results from the transportation and on-site installation stages along with Equation (10). Using this simplified method, the carbon emissions of the case study residential building at the dismantling stage are found to be 14,505.44 kgCO₂e.

5. Discussion

This study has developed a model that can calculate the carbon emissions of prefabricated decorations. The calculation results of the case study project are now discussed with reference to the carbon emissions of prefabricated decoration at various stages compared with the carbon emission levels of traditional decoration. This will provide a fuller understanding of the advantages of prefabricated decoration in terms of reducing carbon emissions.

5.1. Carbon Emissions from Different Materials

The calculation of carbon emissions at the production and transportation stages is directly related to the decoration materials used. Table 10 shows the carbon emissions of the different types of materials used in prefabricated decoration at the relevant stages.

Table 10. Carbon emissions from different decoration materials.

The table shows that the wooden floor generates the most carbon emissions at the production stage, while bamboo-wood fiberboard generates the most carbon emissions at the transportation stage. However, the wooden floor is still the one that produces the most overall carbon emissions in the production and transportation stages. This is mainly because most materials produce far more carbon emissions at the production stage than at the transportation stage, so the transportation stage has a lesser impact on the overall carbon emissions, which also reflects the importance of adopting emission reduction measures at the production stage. Carbon emissions at the production stage are strongly associated with the difficulty of obtaining raw materials, the technical level of the manufacturing plant, the type of materials used in construction, and the amount of construction materials consumed, which can be considered when analyzing measures for reducing emissions. In the case of marble, the carbon emissions at the production stage are not much, while the transportation stage generates more carbon emissions. This type of material should focus on the transportation stage when considering emissions reduction measures.

According to the results of this study, the reduction in carbon emissions during the production stage is primarily related to the consumption of materials and their corresponding carbon emission factors. Apart from the types of materials, there are also some other measures that can affect the quantity of carbon emissions generated during the production phase. At the production phase, the adoption of green materials, energy-efficient production processes, and improving the recycling rate of materials can reduce the carbon emissions from the production phase of prefabricated decorating components. Selecting materials with lower carbon footprints, such as recycled, renewable, or sustainably sourced materials. Applying lean manufacturing principles to minimize waste in the production process. In addition, implementing renewable energy sources, such as solar or wind power, in manufacturing facilities will decrease reliance on fossil fuels. All the measures mentioned above have the potential to reduce carbon emissions from the production phase.

5.2. Carbon Emissions at Different Stages

According to the prefabricated decoration carbon emissions calculations, the carbon emissions at each stage of the prefabricated decoration can be obtained, as shown in Table 11. The data show that the carbon emissions of the building present different focuses and characteristics throughout its life cycle. The share of carbon emissions at each stage is shown in Figure 7.

Figure 7. Carbon emissions percentage at each stage of the prefabricated decoration.

Table 11. Carbon emissions at different stages of prefabricated decoration.

Paying attention to carbon emissions at the operation stage is the first step. The carbon emissions at the operation stage of the case study residential building are 10,065,029.33 kgCO₂e (1218.5 kgCO₂/m²), or 97.98% of the total. Although carbon emissions during the operation stage are produced over a longer timeframe, their impact cannot be ignored. Next are the materialization and dismantling stages, with 1.88% and 0.14% of the total, respectively. The data for the dismantling stage is an estimate based on a simplified model, which provides an approximate view of carbon emissions during the dismantling stage. Considering the relatively small share of the materialization stage and the fact that carbon emissions from the materialization stage are already actually occurring, this stage is discussed separately.

Carbon emissions from the production stage were 177,134.03 kgCO₂e, which accounted for 91.66% of the total amount of the materialization stage. Therefore, taking measures to reduce carbon emissions at this stage is crucial. The transportation stage comes next with 12,213.84 kgCO₂e, accounting for 6.32% of carbon emissions. Carbon emissions during the transportation stage are mainly influenced by material consumption, transportation distance, and transportation mode. The average transportation distance used in this research is a relatively simplified calculation, but the results still show that the transportation stage is essential to reducing carbon emissions from prefabricated decoration.

The on-site installation stage accounted for the least carbon emissions, with only 2.02%, or 3903.32 kgCO₂e. The carbon emissions during the on-site installation stage of the case study residential buildings are closely linked to the prefabricated decoration process, mainly regarding energy savings and reduced labor dependency. Through standardized design and industrialized production, prefabricated decoration components can be precisely manufactured in the factory, reducing the need for operations such as cutting on-site. Therefore, on-site installation avoids using high-energy-consuming mechanical equipment and can be completed with only simple electricity-using equipment. In addition, the classification of work involved in traditional decoration is more complicated, including plumbers, electricians, carpenters, painters, and more than ten types of work involved in the process. Moreover, the on-site installation of prefabricated decoration is highly organized, and only assembly workers are needed at the construction site to assemble the factory-produced parts according to the design requirements, which can achieve higher productivity with less labor.

5.3. Prefabricated Decoration Emission Reduction Potential Analysis

According to the calculation results, a comparison of the carbon emissions of the case study project using two different decoration methods at the production stage and operation stage can be obtained, as shown in Table 12.

Table 12. Comparison of carbon emissions from prefabricated versus traditional decoration.

At the decoration materials production stage, by using Equation (2) and the empirical data collected in the project, the estimated carbon emissions of the case study residential building using traditional decoration methods at the production stage can be calculated. The carbon emissions from applying prefabricated and traditional decoration at this project’s production stage are 177,134.03 kgCO₂e and 249,772.03 kgCO₂e respectively, while the carbon emissions per unit of floor area are 21.44 kgCO₂e/m² and 30.23 kgCO₂e/m² respectively. The carbon emissions per unit floor area of prefabricated decoration are 8.79 kgCO₂e/m² less than those of traditional decoration, and the use of prefabricated decoration in this project reduces carbon emissions by 29.08% in the production stage of building materials compared to that of traditional decoration. This calculation clearly illustrates the significant carbon reduction benefits of prefabricated decoration at the material production stage.

The proportion of carbon emissions from different materials shown in Figures 3 and 4 reveals that carbon emissions from the traditional decoration production stage mainly come from light steel keel, wooden floor, and polyethylene film, while carbon emissions from the prefabricated decoration production stage mainly come from wooden floor, galvanized steel, and bamboo-wood fiberboard. The different types and amounts of materials used in the two types of decoration are directly responsible for the difference in carbon emissions during the production stage. While traditional decoration requires cement mortar, putty, and latex paint, prefabrication completely avoids using such wet-working materials, choosing the more environmentally friendly bamboo-wood fiberboard as the primary material. Therefore, the materials used in prefabrication have lower environmental impacts compared to traditional decoration.

At the operation stage, the data show that compared with the traditional residential building, the carbon reduction benefit of the HVAC system of the project building is 389 kgCO₂/m², which is a reduction of 40.08% of carbon emissions. The carbon reduction benefit of the domestic hot water system is 563.5 kgCO₂/m², reducing carbon emissions by 74.64%. The carbon reduction in the lighting system is 93.5 kgCO₂/m², a 17.35% reduction in carbon emissions. These significant emissions reduction benefits are mainly attributed to the use of prefabricated decoration and the fact that the overall energy efficiency of the building during the operation stage was considered in the design of the prefabricated decoration. The reduction in carbon emissions during the operation phase in the case study of prefabricated decoration compared to traditional decoration can be attributed to the adoption of energy-efficient HVAC systems, the use of air-source heat pumps for domestic hot water, efficient lighting systems, and an integrated design approach that focuses on sustainability. The prefabricated decoration technology, along with the choice of materials and construction methods, contributes to overall energy savings and reduced carbon emissions during the building’s operational life. These measures collectively result in a lower environmental impact during the operation stage compared to traditional decoration methods.

The carbon emissions from transportation prefabricated decorating components are calculated at 12,213.84 kgCO₂e, 32.85% lower than traditional decoration transportation. The case study project uses industrialized means to solve complex decoration construction problems, including the use of prefabricated decoration parts manufactured and assembled in the factory to avoid the waste of materials brought by on-site construction. The material utilization rate of prefabricated decoration is improved, and the transportation turnover of the parts distribution process is reduced. Prefabricated floor systems can eliminate the need for wet-work materials, which saves transportation by reducing the number of vehicle trips without changing the type of vehicle or distance traveled, thus reusing transportation carbon emissions.

In addition, the project utilizes prefabricated bathroom systems manufactured in the factory and then assembled on-site. The composition of the prefabricated bathroom is shown in Figure 8. This method ensures that the flatness of the wall and the precision of the gaps between the tiles reach a high standard that is difficult to achieve with traditional methods while effectively eliminating leakage problems. The installation can be completed quickly with only two workers working for 4 h on-site, and the on-site environment is clean during the construction process, with almost no excess construction waste generated. In contrast, traditional bathroom decoration needs to rely on the skill level of the workers. Its waterproof treatment and tile laying are often prone to leakage, peeling, and other decoration quality problems. Traditional wet construction usually takes 15–20 days to complete and generates large amounts of construction waste and dust. Compared with prefabricated decoration, the construction speed is slower, and the construction quality problems and environmental impact are also more serious.

Figure 8. Prefabricated bathroom system.

Considering the increasing maturity of prefabricated decoration, there is a challenge and an opportunity to achieve greater carbon reduction targets in future projects. One challenge is that the manufacture of prefabricated decorations is centralized in factories, generating significant front-end energy consumption, particularly when processes such as drying and curing are used. The other important challenge is that, as mentioned in the previous comment, certain materials, such as wooden floors and bamboo, can contribute significantly to carbon emissions. The industry needs to explore alternative materials and production methods that align with sustainability goals. Opportunities arise from advancements in technology, enabling more energy-efficient transportation strategies and refining production processes. Embracing innovative materials, optimizing transportation, and integrating sustainable practices throughout the life cycle can significantly reduce carbon emissions in future projects. Continuous research, development, and industry collaboration will play a crucial role in realizing these opportunities and addressing the challenges associated with the increasing maturity of prefabricated decoration.

In addition, incorporating circular economy principles into the production process and design of prefabricated decorations is challenging. Designing recyclable and reusable components and promoting zero-waste concepts requires more in-depth research and innovation. To address these specific material challenges, three strategies have been developed: (1) improve the production methods of the high-carbon emission materials; (2) replace the materials with more environmentally friendly materials; and (3) optimize the transportation strategies. Since the production phase of materials generates the largest proportion of carbon emissions, it could be effective to reduce carbon emissions by improving the production methods or replacing the high-carbon emission materials with lower ones. In addition, moving factories, such as wood floor production factories, closer to construction sites can reduce carbon emissions. In addition, as the global prefabricated decoration market grows, larger-scale production can lead to the development of a globalized supply chain, and more environmentally friendly and cost-effective production options are available to reduce carbon emissions.

5.4. Prefabricated Decoration Emission Reduction Strategies

Although prefabricated decoration effectively reduces carbon emissions in actual projects, there is still room for improvement. Achieving further reductions in carbon emissions requires clear and feasible strategies and measures.

The operation stage with the highest carbon emissions is inextricably linked to the energy-efficient design of the building and the users’ awareness of energy efficiency. Raising users’ awareness of energy conservation is crucial, as their behavior and habits directly affect the building’s carbon emissions during operation. Providing easy-to-understand information about energy-efficient practices, such as proper usage of heating and cooling systems, can enhance user awareness. Additionally, workshops and training sessions can be organized to empower users with the knowledge and skills needed for regular maintenance. Creating user-friendly guides and manuals for maintaining prefabricated elements and promoting the use of eco-friendly products further encourages sustainable practices. Furthermore, carbon emissions reduction requires a regular maintenance program that includes inspection and maintenance of the prefabricated decoration, including the building’s heating, ventilation, air conditioning, electrical, and water systems. This helps to ensure that these systems operate efficiently and reduces the risk of energy waste. In addition, regular energy efficiency assessments of the building need to be carried out, which in turn provide real-time information to managers about the energy use of the building. This helps to identify potential energy-saving opportunities and problems and to take steps to improve energy efficiency. Relevant policies and incentive programs can be implemented to encourage user awareness and regular maintenance practices for reducing carbon emissions in buildings with refabricated decoration.

In the production stage, strategies to further achieve carbon emission reduction by increasing the use of green materials, introducing energy-efficient production processes, and improving the recycling rate of materials Raising users’ awareness of energy conservation is crucial, as their behavior and habits directly affect the building’s carbon emissions during operation. Education and publicity campaigns are the first steps to convey to households the necessity of reducing carbon emissions and conserving energy. Wasteful use of energy in daytime lighting and turning on the air conditioner when no one is in the room will increase carbon emissions, so residents need to develop good habits to save energy and reduce emissions. Incentive programs can be established to encourage residents to adopt energy-saving measures. Rewards can be partial reductions in energy bills, the provision of energy-efficient equipment, or other incentives to motivate them to conserve energy.

At the transportation stage, carbon emissions can be further reduced by rationally planning transportation routes, choosing suppliers that are closer to the project site, and avoiding secondary transportation as much as possible. Advanced transportation management software can be used to plan the optimum routes, minimizing the distance traveled.

Although the on-site installation stage has a smaller carbon footprint, it cannot be ignored. The emission reduction potential of prefabricated decoration can be further realized through a highly organized installation process according to the design requirements, which can achieve higher productivity with less labor. It is necessary to formulate detailed process and task plans and harmonize construction regulations and operating procedures to ensure that each construction step is accurately planned and coordinated. The carbon reduction potential can be further enhanced by integrating prefabrication technology with digital technology; for example, BIM can provide details of the construction process, reducing errors and improving installation efficiency.

At the dismantling stage, carbon emissions can be further reduced by optimizing demolition methods, disposing of demolition materials close to the site, and enhancing the recycling and reuse of materials for prefabricated decoration. During the demolition process, different parts of the prefabricated decoration should be finely decomposed and categorized for subsequent recycling and reuse. For the transportation of demolition items, the principle of proximity is adopted, with preference given to treatment facilities closer to the demolition site, such as recycling stations, treatment centers, or recycling factories. During the decoration process, materials used are categorized and labeled to be more easily identified and recycled during the demolition stage.

6. Conclusions

By developing a measurement model for prefabricated decoration carbon emissions and applying it to a case project, this study offers a detailed evaluation of prefabricated decoration projects’ carbon emissions, which will help to extend and deepen the theoretical basis of the carbon emissions assessment methodology for prefabricated decoration. The model analyzes the sources of carbon emissions at each stage and considers multiple variables and influencing factors to guarantee the evaluation’s accuracy and comprehensiveness. The findings of this study have theoretical and practical contributions.

From a theoretical point of view, this study provides a more comprehensive and accurate methodology for prefabricated decoration carbon emissions assessment while injecting a new theoretical paradigm and methodological foundation into the field of carbon emissions assessment. Prefabricated decoration is gradually being used more and more in the construction industry, but the understanding and quantifying of its carbon emissions level is still insufficient. This paper not only demonstrates the environmental benefits of prefabricated decoration but also emphasizes the need for transitioning from traditional to prefabricated construction. The comparative analysis between prefabricated and traditional decoration methods contributes empirical evidence to the broader discourse on sustainable building practices.

From a practical point of view, the results of this research can accelerate the technological innovation of the decoration industry. The calculation results can be used as a reference for decoration enterprises to develop prefabricated decoration and help stakeholders understand the carbon emissions level and development potential of prefabricated decoration in depth. Decoration companies can use the results of this study to optimize the carbon emission reduction potential of prefabricated decoration projects, improve building sustainability, and reduce operating costs. It can also provide a basis for the government to develop relevant laws, policies, and standards to encourage the adoption of prefabricated decorations. This paper emphasizes the importance of collective action from the government, enterprises, designers, and industry associations, providing a framework for overcoming challenges and facilitating the broader adoption of prefabricated decoration in the construction industry.

In this study, a calculation model was developed to measure the carbon emissions of prefabricated decoration throughout its life cycle. The key findings of this study are summarized as follows: (1) The carbon emissions characteristics of each stage were derived by calculating and analyzing the carbon emissions of the residential building’s prefabricated decoration. The operation stage of the residential building in the case study, with carbon emissions of 1218.5 kgCO₂/m², is the most significant stage in terms of carbon emissions. Next to the operation stage is the production stage with 177,134.03 kgCO₂e, followed by the demolition stage with 14,505.44 kgCO₂e, and the transportation stage with 12,213.84 kgCO₂e. The on-site installation stage has the smallest share of the prefabricated decoration’s total lifecycle carbon emissions, with only 3903.32 kgCO₂e. Carbon emissions patterns from prefabricated decoration can be used to better formulate emission reduction strategies at each stage. (2) Through the calculation and comparative analysis of carbon emissions from using prefabricated decoration and traditional decoration in the case of residential buildings, it is possible to confirm the effectiveness of prefabricated decoration in reducing carbon emissions. Calculations show that using prefabricated decoration in this project reduces carbon emissions by about 29.08% compared to traditional decoration in the production stage. Optimized design through prefabricated decoration reduces carbon emissions by 1046 kgCO₂/m² for this building operation. Since increasingly mature prefabricated decoration offers lower cost, faster speed, and higher quality, it will eventually replace traditional decoration.

Although the advantages of prefabricated decoration are obvious, there are still barriers to its practical promotion and application. In China’s current development of prefabricated decoration, the cost of materials and design has not been significantly reduced. Although prefabricated decoration may be more economical in the long run, the initial investment cost is higher. The lack of technical standards and regulations may also limit prefabricated decoration on the market. In addition, traditional decoration usually allows for greater flexibility and individualization, whereas prefabricated decoration can be limited by the design, making it difficult to adjust the initial design during construction. Promoting prefabricated decoration to replace traditional decoration requires concerted efforts from all parties, including the government, enterprises, designers, and relevant industry associations. Through technological innovation, policy support, the establishment of industry standards, and market promotion, these challenges can be gradually overcome to realize a wider application of prefabricated decoration in the construction industry.

Due to data collection limitations, the data were not sufficient to calculate all the carbon emissions values for certain stages and were not able to consider the effects of all possible factors; the carbon emissions of the moisture-proof and waterproof parts of the prefabricated decoration according to its special climate characteristics are not considered in this study; and carbon emissions from the recycling and reusing of the prefabricated decoration are not included in this research. The limitations are caused by the limited carbon emission factors database, which may lead to a deviation in the total carbon emissions calculated. Therefore, in future studies, it could be beneficial to expand the scope of data collection. For the data that cannot be directly collected, it could be estimated based on relevant data, models developed by previous studies, or expert interviews. Additionally, with the application of clean energy, process improvement, and the promotion of energy-saving technologies, carbon emissions factors could be updated. The carbon emissions of prefabricated decoration material recycling and reuse could be assessed to quantify the emission reduction benefits of recycling and reuse by examining the carbon emissions from the process, including the energy demand for reprocessing, repairing, or reinstalling.

Author Contributions: Conceptualization, J.B., C.L. and J.L.H.; methodology, C.L., C.Z. and W.M.; analysis, J.B. and C.L.; study design, J.B. and C.Z.; investigation, C.C.; data curation, C.L. and J.L.; writing—review and editing, J.B., C.L., J.L.H. and W.M.; writing—original draft preparation, visualization, B.D.; project administration, C.C. and J.L.; supervision, J.L.H. and W.M. All authors have read and agreed to the published version of the manuscript.

Funding: This research was funded by National Natural Science Foundation of China, grant number 52078318.

Data Availability Statement: The data presented in this study are available on request from the corresponding author. The data are not publicly available due to privacy.

Conflicts of Interest: Authors Chunyang Zuo and Jixuan Liu were employed by the company China Overseas Grand Oceans Lowcarbon Technology Co., Ltd. Author Congda Chen was employed by the company Suzhou KELIDA Co., Ltd. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

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