Dynamic Window Technologies for Energy Efficiency in Condominiums in Tropical Climates

Abstract

This study investigates the application of dynamic window technologies in condominiums located in hot and humid climates, focusing on Thailand. The research integrates both passive and active window designs aimed at reducing energy consumption by maximizing natural ventilation and daylight, while minimizing heat gain. Dynamic windows, equipped with shading devices, automated controls, and stack-effect ventilation, can achieve significant energy savings by decreasing the need for air conditioning and artificial lighting. The energy performance was assessed through simulations based on Thailand’s Building Energy Code (BEC), resulting in a potential reduction in energy consumption by 3.29 kWh/m² annually or approximately 1.6% annually. Moreover, economic analysis showed that applying dynamic windows in condominiums could save up to 506.38 baht per room per year. The lifecycle cost analysis supports their long-term financial viability, achieving payback within 18.4 years and generating further net savings post-payback. The study concludes that dynamic windows are both scalable and sustainable, offering a viable solution for urban developments in tropical regions.

1. Introduction

Energy consumption in residential buildings, particularly in hot and humid climates, is a significant concern due to the increasing demand for air conditioning. In Thailand, condominiums have become a common residential option, and their energy usage is a pressing issue. Thailand’s Energy Efficiency Plan 2015–2036 (EEP 2015) has emphasized the need for more energy-efficient buildings, especially condominiums with an area of 10,000 square meters and greater, which must comply with the Building Energy Code (BEC) [1,2]. The adoption of energy-saving technologies, such as dynamic window systems, is crucial in achieving these efficiency goals.

Dynamic window technologies offer a solution to energy overconsumption by leveraging both passive and active design strategies. Passive strategies include maximizing natural ventilation and daylight, while active components, such as automated shading systems, help reduce solar heat gain. These technologies aim to lower the reliance on artificial lighting and air conditioning, thus significantly reducing energy demand in condominiums. In the context of Thailand’s hot and humid climate, where cooling loads dominate energy consumption, such innovations hold significant promise [3].

Building envelopes play a crucial role in energy consumption, accounting for up to 50% of heat gain or loss in buildings [4]. Windows are especially critical in this aspect, as they often contribute to over 20% of the energy loss in conventional designs [4]. Traditional windows in condominiums often fail to control solar heat gain effectively, leading to excessive cooling requirements. Therefore, developing and deploying dynamic windows that provide passive and active control of heat gain and natural ventilation is necessary for reducing energy consumption in tropical urban areas

Dynamic windows use technologies to adjust the amount of light and heat passing through the glass. This technology can reduce solar heat gain in the summer while allowing more light and heat in during the winter [5]. By automatically adjusting to external conditions, these windows can maintain comfortable indoor temperatures without relying heavily on air conditioning. Furthermore, integrated shading devices and daylighting technologies, such as light louvers, can enhance the efficiency of these windows by redirecting natural light into the building while minimizing glare and heat.

One of the primary challenges for the widespread adoption of dynamic windows is cost. Currently, the cost of installing such systems remains higher than conventional windows, particularly in residential settings. However, research has shown that dynamic windows can provide significant long-term savings through reduced energy consumption. According to studies, dynamic windows could decrease total energy use in condominiums when compared to traditional windows. The payback period for these technologies, especially when combined with government incentives and energy efficiency programs, makes them a viable option for the future.

In conclusion, dynamic window technologies represent a key solution to addressing the energy challenges faced by condominiums in Thailand’s hot and humid climate. By combining passive and active design elements, these windows can significantly reduce the need for artificial cooling and lighting, thus aligning with the country’s energy efficiency goals as set out in the EEP 2015 [1].

2. Literature Review

The design for energy efficiency requires the implementation of passive strategies in the early stages to minimize energy consumption and enhance indoor thermal comfort [6]. The building envelope can cause high temperatures in indoor environments through the following factors: solar heat through the glazing, convective heat gains, and conductive heat gains [6]. Shading devices and natural ventilation have been proven to be the most effective improvement of building performance relating to energy saving [7].

2.1. Passive Design Theories

In tropical climates like Thailand, buildings face the challenge of high solar heat gain, which significantly increases cooling loads. To address this, passive design strategies are employed to optimize natural ventilation, daylighting, and shading, reducing the reliance on mechanical systems. Passive designs focus on controlling the indoor climate by utilizing external factors like shading devices, natural air movement, and advanced window technologies.

Shading Devices are crucial in minimizing heat gain while maintaining adequate daylight. According to Baker (1987), overhangs and cantilevered shading prevent direct sunlight from entering the building while still allowing for natural ventilation, which is critical in reducing cooling demand during peak hot periods [8]. However, in an attempt to exclude intense sunlight, buildings in tropical climates often employ robust shading devices that block a considerable amount of daylight, which results in the need for artificial lighting throughout the day. To reduce the need for artificial lighting, dynamic shading devices that respond to varying daylight may be used instead of traditional ones [8]. Through the provision of shading using panels that can be folded vertically and horizontally, the building can be protected from the sun, heat, glare, and rain while simultaneously giving the residents some privacy. The dynamic shading, which adjusts based on sunlight intensity, can provide a more balanced solution.

Stack-effect Ventilation enhances energy efficiency by using the natural movement of warm air. This process allows warm air to rise and escape through high openings, while cooler air is drawn in through lower inlets, promoting natural ventilation without the need for mechanical cooling [8]. In hot and humid climates, traditional architecture often emphasizes air movement, as steady breezes help achieve thermal comfort naturally.

2.2. Active Window Technologies

Active window technologies have seen significant advancements, particularly in high-energy-demand regions. These windows can reduce solar heat gain during the day and allow more light in during cooler periods [5]. Light Redirection Systems, such as louvers, help to distribute natural light further into the building’s interior, reducing the need for artificial lighting. By redirecting daylight deeper into the building and controlling glare, these systems offer significant energy savings, especially in tropical climates where both heat and light must be managed effectively [5].

2.3. Case Studies and Applications in Tropical Climates

The façade of the Institute of Physics and Astronomy, University of Potsdam serves as a leading case study where dynamic shading systems—perforated aluminum façades—were employed to reduce energy consumption while optimizing daylighting. This dynamic shading system has installed perforated aluminum façades across 1225 square meters, with horizontally folding shutters that open and close depending on shading needs, making the façades dynamic by adapting their form and view. Key elements include louvers made from materials like aluminum, red cedar, and glass [9]. One of the great examples in Asia is the Monsoon Window design of the State Mortgage Bank in Sri Lanka, created by Geoffrey Bawa. The façade features a clerestory with an overhang at the top, a central pivot window, and a recessed windowsill with an air intake below. The key feature is the ventilation slot in the windowsill, which allows air to flow into the building even when the windows are closed, such as during rainy weather. This ensures continuous airflow and ventilation, maintaining indoor comfort regardless of external conditions [10,11].

Studies from Potsdam indicate that horizontally folding shutters are particularly effective for hot and humid climates, with electricity as the primary power source and manual operation as a secondary option. Similarly, the Monsoon Window is designed to enhance ventilation during heavy rains while minimizing solar heat gain, demonstrating the potential for similar systems in Thailand.

The review of theories and applications highlights the growing importance of passive and active design strategies in improving energy efficiency in tropical climates in

Table 1. Summary table of theories and applications.

Theory/Technology	Description	Application in Tropical Climates
Stack-Effect Ventilation	Allows warm air to exit through upper openings and cooler air to enter through lower ones [8].	Reduces the need for mechanical cooling during hot periods by natural ventilation.
Cantilevered Shading	Overhangs block direct sunlight while allowing ventilation [8].	Reduces solar heat gain while maintaining airflow.
Light Redirection Systems	Redistributes daylight deeper into the interior to reduce the need for artificial lighting [5].	Minimizes artificial lighting and cooling costs.
Monsoon Windows	Tailored for tropical climates to optimize ventilation during heavy rains while reducing solar heat gain [10,11].	Improves air circulation and reduces solar heat gain in high-rise buildings.

. Both passive and active strategies are essential in reducing cooling loads and promoting sustainability. These systems have the potential to significantly lower energy consumption in urban residential buildings, aligning with Thailand’s energy efficiency goals.

3. Methodology

The research methodology employed in this study is divided into five key phases: literature review, design, simulation, optimization, and visualization, aimed at developing dynamic window technologies for energy efficiency in tropical condominiums. The primary objective is to reduce energy consumption in condominiums located in hot and humid climates like Thailand.

• Literature Review and Research: This phase involved gathering existing knowledge from academic sources and case studies related to passive and active window technologies. The review focused on technologies that optimize natural ventilation, daylighting, and heat gain control, in line with the Building Energy Code (BEC) of Thailand [2];
• Design: Parametric models of building envelopes and windows were created based on case study insights and the BEC guidelines. The models considered factors such as shading devices, window placements, and dynamic features like automated louvers to enhance passive ventilation while minimizing solar heat gain;
• Simulation: Energy simulations were conducted using Grasshopper on Rhino v.6 with the Energy Plus plugin v.9.1 to assess the performance of dynamic windows against traditional models. Parameters like solar radiation intensity and material thickness were drawn from the Ministry of Energy’s 2021 [12], guidelines on energy conservation standards and used with Bangkok’s EPW weather data named Bangkok 484560 (IWEC) [13]. The simulation considered monthly variations to capture seasonal differences in solar radiation, daylighting, and airflow, optimizing for energy efficiency and comfort under tropical conditions;
• Optimization: The simulation results were used to adjust window design elements, including the dimensions of cantilevered shading devices and the functionality of stack effect ventilation. The goal was to maximize human comfort while meeting energy-saving targets established by Thailand’s BEC;
• Visualization and Mock-Up: A 3D model of the optimized dynamic window design was developed, allowing for a detailed exploration of its performance. A scaled prototype was built to test its functionality in real-world conditions, ensuring its effectiveness in reducing energy consumption and improving thermal comfort.

This methodological approach ensures that the dynamic window technologies developed in this study are both practical and scalable, offering significant potential for energy savings in condominiums across tropical climates.

4. Results

This section presents the results of the study on dynamic window technologies for energy efficiency in tropical condominiums, focusing on three key areas: physical components of dynamic window technologies, window materials, and energy simulation of dynamic windows. The simulations and analysis were conducted based on Thailand’s Building Energy Code (BEC), which is designed to optimize energy consumption and improve sustainability in hot and humid climates.

4.1. Physical Components of Dynamic Window Technologies

There are three main components for this dynamic window. First, the cantilevered sun shading is useful for the summer and rainy seasons in tropical regions, and it allows unobstructed views from the inside as well as the outside of the building, as shown in Figure 1. Second, the horizontal folding shutters can be operated manually or automatically via the natural light sensor attached to them, as shown in Figure 2. The individual shutter attached to the window changes its form as a dynamic window. These shutters are made from simple and standard materials like aluminum and perforated aluminum. The main materials of these shutters are the basic components of windows in Asia and Thailand [14]. Whether these shutters are automatically or manually operated, electricity remains the vital source of power for window operation.

Figure 3 shows the third component of this dynamic window, which is the stack effect ventilation window. Typical windows in condominiums only have one sliding window that allows natural ventilation. Moreover, the study found that it would be more effective to conserve energy in air-conditioned buildings if glass were used instead of a shading device since glass can reduce more solar heat gain as measured by the coefficient of solar heat gain of glazing glass (SHGC) and that of the shading device (SC) [15]. In addition, the better the glass quality used, the more effective the energy conservation will be. This research created a new form of window which consists of an additional two small windows; one is located above the main sliding window, while the other is below it. Stack effect ventilation windows allow warmer air in the room to rise and leave the window from a higher opening outlet, replaced by heavier, cooler air through a lower inlet underneath the main sliding window. According to the results in Figure 3, the new dynamic window has a better ventilation system than the typical window because the stack effect ventilation can simulate more natural ventilation in the room.

4.2. Window Materials

According to the study, the materials used to make dynamic windows are suggested in

Table 2. Window materials for window installation.

Parameter	Applications
1. Sun control	An external shading device and dynamic horizontally folding window associated with a lighting sensor.
2. Natural ventilation	The horizontal opening allows a breeze without rain. Occupants operate a sliding aluminum shelf. The horizontal opening is used at night without using air-conditioning.
3. Daylighting	Integrate
4. Connection to outdoors	N/A
5. Thermal insulation	N/A
6. Structural Efficiency	Lightweight Concrete Thickness Conductivity (W/(m.°C)) Density (kg/m3) Specific Heat (J/kg. °C)	620 kg/m3 0.076 m 0.18 620 840	Plaster Thickness Conductivity (W/(m.°C) Density (kg/m3) Specific Heat (J/kg.°C)	0.015 m 0.72 1860 840
7. Material choices	Laminated Ocean Green (Low E) Thickness U-Value SHGC Visible Transmittance Tvis	+6 mm +0.76 mm +6 mm 5.63 0.52 0.74	Aluminum N/A
8. Controllers	Automation system 1. Arduino 2. Lighting sensors		Manual system Switching to the manual system
9. Energy generation	Electricity

. Aluminum serves as the primary material for constructing various window components, including cantilevered sun shades, the main window frame, stack ventilation openings, and horizontal folding shutters. As mentioned above, glass is more effective in conserving energy than other shading devices as it can reduce solar heat gain. Furthermore, this research recommended using laminated Ocean Green (Low E) as it is of better quality than the typical glass used in windows [5]. All these suggested materials are also used as a parameter for energy consumption analysis by Grasshopper on the Rhino program v.6 with the Energy Plus plugin v.9.1. The result will be illustrated in the next topic.

4.3. Energy Simulation of Dynamic Windows

Multiple energy simulation programs have been used and applied for different design purposes [16]. According to [17], this research will use the Sketchup program v.2019 and Plugin for the first draft of the design process. Then, the Rhino program v.6 and Grasshopper plugin will be the second process to simulate the energy analysis [16,17].

4.3.1. Solar Radiation Analysis

The solar radiation analysis was conducted by testing three different aspects of dynamic windows as in

Table 3. Three different aspects of dynamic windows for testing.

Condominium	Elevation	Perspective	Section
Window 1
Window 2
Window 3

to determine their effectiveness in reducing solar heat gain throughout the year. Each model was tested on the south-facing side of the condominium unit, as the south orientation in tropical climates typically experiences the highest levels of solar radiation. Each model was assessed quarterly (January–March, April–June, July–September, and October–December) to reflect real-world sun intensity and angle variations in a tropical climate. The models were analyzed for their ability to block solar energy and reduce cooling loads while maintaining daylight. The best-performing model was identified in each period by measuring energy savings in kWh/m², aiming to achieve an optimal balance between daylight usage and solar heat reduction.

Overall, the solar radiation analysis in

Table 4. Summary table: solar radiation analysis by quarter.

Period	Solar Radiation Blocked (kWh/m2)	Best Performing Window
1 Jan–31 Mar (South)	20.5	Window 1
1 Apr–30 Jun (South)	24.7	Window 2
1 Jul–30 Sep (South)	18.3	Window 1
1 Oct–31 Dec (South)	19.2	Window 3
Annual Average (South)	20.7	-

indicated that each window had strengths depending on the season, Window 1 proved to be the most suitable for year-round performance. Window 1 was able to consistently block significant solar radiation across all seasons, with an annual average of 20.7 kWh/m². It provided reliable solar protection while still allowing sufficient daylight penetration. Window 1 offers the most balanced performance. Its ability to manage solar radiation in both peak and off-peak periods makes it the most practical choice for long-term application in tropical condominiums. By adopting Window 1, energy savings can be maximized across varying seasonal conditions, ensuring better indoor thermal comfort and reduced cooling loads over time, as shown in Figure 4 and Figure 5.

In order to test cantilevered sun shading response to solar radiation analysis, the criteria will be set into four periods per year as shown in Figure 4. The testing will be a test on the South side.

In order to test horizontally folding shutters’ automatic response to solar radiation analysis, the criteria will be set into three different angles of automatic adjustment, as shown in Figure 5. The testing will be a test on the South side.

According to passive and active design strategies, the window’s performance to climate response is seen in the results. For example, both cantilevered sun shading responses and automatic horizontally folding shutters can protect solar radiation against windows and interior space accordingly without obstructed views outside.

4.3.2. Annual Daylight Analysis

The annual daylight analysis focuses on comparing two window models: the existing fixed windows in condominiums and newly implemented dynamic window technologies. The testing models are based on the results from the solar radiation analysis in Table 4 and Figure 4 and Figure 5, where dynamic windows demonstrated superior solar control. Daylight simulations were performed on the southern and western façades due to their exposure to intense solar radiation in tropical climates like Thailand. The southern façade is subjected to continuous sunlight throughout the year, while the western façade receives strong afternoon sunlight, particularly during the summer months. These orientations were selected to understand how different window systems affect daylighting performance under varying conditions.

The comparison between the existing windows and the dynamic windows technology shows that the performance of annual daylight analysis of dynamic window technology leads to fewer daylight amounts than the existing window in

Table 5. Comparison of annual daylight analysis between existing windows and dynamic windows technology on the South side.

Comparison	15 Jan 16.00	15 Apr 16.00	15 Jul 16.00	15 Oct 16.00
Existing Windows in Condominiums
Dynamic Window Technology in Condominiums

and

Table 6. Comparison of annual daylight analysis between existing windows and dynamic windows technology on the West side.

Comparison	15 Jan 16.00	15 Apr 16.00	15 Jul 16.00	15 Oct 16.00
Existing Windows in Condominiums
Dynamic Window Technology in Condominiums

. Dynamic windows help maintain these optimal lighting levels by adjusting the amount of daylight entering the room, preventing over-illumination during peak sunlight hours, and ensuring adequate light during cloudy periods or in low-light conditions. These simulations show that dynamic windows are particularly effective in meeting tropical climate requirements, compared to traditional windows that may cause excessive glare due to poor solar control.

4.3.3. Prototype of Dynamic Window Technologies

In order to identify the possibility of producing windows, the prototype of a dynamic window will be drawn and proved by making the prototype model, as shown in Figure 6. The research finds that this prototype also requires additional technical components: Arduino Uno as a microcontroller board, light sensors, and switches for the manual adjustment system, as shown in Figure 7, Figure 8, Figure 9 and Figure 10.

A scaled prototype (1:25) was developed and tested under real-world conditions to verify its functionality. Findings from this study indicate that the dynamic window technologies created are both feasible for practical implementation and scalable, demonstrating significant potential for energy savings in tropical condominium environments. The successful performance of the prototype affirms that producing these dynamic windows on a larger scale is achievable, with the technologies functioning effectively in alignment with the tested model.

4.3.4. Ventilation Performance and Stack-Effect Analysis

The Ventilation and Stack Effect Analysis evaluates the performance of three window designs, as shown in Table 3, under different wind speeds to determine their effectiveness in promoting natural ventilation and enhancing the stack effect. Average wind speeds for the months of January, April, July, and October in Hat Yai, Thailand were selected based on data from Climate and Average Monthly Weather reports [18]. These months represent seasonal variations, with average wind speeds as follows: January at 5 m/s, April at 3 m/s, and July and October at 2 m/s. These speeds were used as testing criteria to understand how each window type responds to varying wind conditions.

The chosen wind speeds serve as key variables for testing, simulating typical conditions that the windows might encounter throughout the year. By analyzing each window type’s response to these wind speeds, the study aims to identify the design most effective in facilitating airflow and promoting natural ventilation within a tropical climate.

Dynamic window systems in tropical climates harness stack-effect ventilation to enhance natural airflow and minimize reliance on mechanical cooling. Stack-effect ventilation operates through natural pressure differences: warm air rises and exits via upper windows, while cooler air is drawn in through lower inlets. This effect creates a consistent airflow, improving thermal comfort and reducing energy consumption. The analysis below evaluates airflow rates across three window models, using simulations based on varying wind speeds in Thailand.

Airflow Rate Analysis

Dynamic windows (Table 3) were tested under wind conditions that simulate seasonal variations, with average wind speeds set to 5 m/s (January), 3 m/s (April), and 2 m/s (July and October) in

Table 7. Testing wind speed from the plans of windows 1, 2, and 3.

Wind Speed (m/s)	Window 1	Window 2	Window 3
January (5 m/s)
April (3 m/s)
July (2 m/s)
October (2 m/s)

. Temperature differentials of 3–5 °C were applied to initiate the stack effect, aligning with effective ventilation parameters in tropical climates.

Table 8. Airflow rate analysis.

Wind Speed (m/s)	Window 1	Window 2	Window 3
January (5 m/s)	3.8 m/s	3.2 m/s	2.9 m/s
April (3 m/s)	2.5 m/s	2.2 m/s	1.8 m/s
July (2 m/s)	1.6 m/s	1.4 m/s	1.1 m/s
October (2 m/s)	1.7 m/s	1.3 m/s	1.0 m/s

below presents the airflow rates and effectiveness of each model under these conditions.

This simulation confirms that Window l consistently achieved optimal airflow rates, maintaining effectiveness across all wind speeds and demonstrating superior ventilation performance suitable for tropical settings.

Stack-Effect Ventilation Efficiency

The stack-effect efficiency was further analyzed by examining vertical airflow under temperature differentials typical of Thailand’s tropical climate (3–5 °C). Window 1 showed the best vertical airflow, effectively using the stack effect for natural ventilation, as shown in

Table 9. Stack-Effect Ventilation Efficiency.

Wind Speed (m/s)	Window 1	Window 2	Window 3
January (5 m/s)	3.5 m/s	3.0 m/s	2.8 m/s
April (3 m/s)	2.3 m/s	2.0 m/s	1.6 m/s
July (2 m/s)	1.5 m/s	1.3 m/s	1.0 m/s
October (2 m/s)	1.5 m/s	1.2 m/s	1.1 m/s

.

Summary of results that Window 1 proved most effective in both natural and stack-effect ventilation. By utilizing stack-effect principles and optimizing airflow rates, dynamic windows offer a robust, energy-efficient solution that aligns with sustainability goals for tropical buildings, providing both environmental and economic benefits.

4.3.5. System Durability and Operational Resilience

Maintenance Implications and Analysis of System Longevity

Automated Control System and Failure Management: The Arduino-based automated control system, equipped with light sensors, dynamically adjusts window shading to optimize energy savings. However, potential issues, such as sensor malfunctions or power outages, require a maintenance plan. Key components like the light sensor and Arduino board have a lifespan of approximately 3–5 years, necessitating periodic checks and replacements to maintain performance.

Maintenance and Long-Term Energy Savings: Regular maintenance is essential to sustain energy efficiency over time. The aluminum window frames, designed to last 37–41 years under standard conditions, require minimal upkeep [19]. This durable framing minimizes replacement costs compared to electronic components, ensuring the system remains cost-effective and energy-efficient over its lifespan. Proper upkeep of these systems guarantees that both automated shading adjustments and frame integrity support long-term energy savings effectively.

Analysis of System Reliability Enhancement and Redundancy

Detection and Correction of Light Sensor Malfunctions: Establish methods to detect sensor errors, such as monitoring for unusual values or signal loss. When a malfunction is detected, the system can default to a backup mode, maintaining energy-saving functionality.

Power Outage Handling: Implement backup power solutions, like UPS, to ensure continuous operation during outages. The system will automatically reset upon power restoration and verify sensor functionality.

Failure Prevention and Redundancy Measures: Introduce redundancy by pairing sensors, allowing one to take over if the other fails. Integrate multiple sensor types to maintain functionality in diverse conditions.

Software Control Management: Program continuous monitoring and user alerts for abnormal readings, enabling the system to pause operations and prevent disruptions, thereby ensuring consistent and reliable performance.

An analysis of system durability and operational resilience highlights measures that enhance resilience, ensuring sustained energy efficiency and reliability over time.

4.4. Energy Savings

The research complies with the Building Energy Code and related policies mandating energy-efficient condominium designs in Thailand. Net Energy Consumption derived from modeling building type under each level of energy saving capability. Building Energy Code of Thailand states that the energy consumption of condominiums should be less than 211 kWh/m²/y.

The energy simulations compared the performance of dynamic windows with traditional fixed windows under the same conditions. Dynamic windows incorporated shading devices that adjusted automatically based on sunlight intensity, preventing solar heat gain during the day. As a result, the annual energy consumption in rooms equipped with dynamic windows was reduced from 203.50 kWh/m² to 200.21 kWh/m², reflecting a 3.29 kWh/m² annual reduction in energy usage. This energy savings is equivalent to a reduction of approximately 1.6% annually, which is a significant amount given the high cooling demand in tropical climates. In a practical scenario, for a condominium room with an area of 32.75 sqm, the cooling load was reduced by 366.44 kWh per month, decreasing from 14,495.02 kWh to 14,128.58 kWh. These savings were attributed to the reduced reliance on air conditioning, particularly during the hottest periods of the day. The windows minimized solar heat gain by automatically adjusting the shading, thereby reducing the temperature inside the room and preventing the overheating commonly experienced with traditional windows.

The findings also indicated that the type and orientation of the window significantly impacted the level of energy savings. Windows facing direct sunlight required more advanced shading and glazing solutions to minimize heat gain, while windows on shaded or less exposed facades benefited from optimized daylighting features. Dynamic windows that incorporate both passive and active design elements, such as automated shading, heat-reflective coatings, and optimized airflow systems, contributed to the largest energy savings. Overall, these results align with the country’s energy efficiency targets as outlined in the Energy Efficiency Plan 2015 [1], further emphasizing the role of dynamic window technologies in achieving sustainable urban development.

Dynamic windows demonstrated significant potential in reducing energy consumption in condominiums, with reductions ranging from 10% to 30% depending on the design, type, and placement of windows [4]. This was made possible through the integration of shading devices and dynamic ventilation mechanisms, which reduced the need for air conditioning during peak daylight hours.

4.5. Economic Viability and Lifecycle Cost Efficiency

4.5.1. Cost Efficiency

The economic analysis of dynamic windows revealed substantial cost savings, making them a viable option for middle-class condominiums in Thailand. The majority of middle-class condominiums in Thailand with a room size between 30 and 35 sqm [20]. The simulation of the energy consumption index of dynamic window technologies in a 32.750 sqm room shows that dynamic window technologies have energy consumption within the standard rate according to the Building Energy Code of Thailand. The simulation results indicated that the use of dynamic windows led to an annual energy savings of approximately 506.38 baht per room. For a condominium building with 1000 units, this translates to a total annual savings of 506,380 baht in

Table 10. Money saving by using dynamic window technologies per year/per unit.

Unit Room Number/ 1 Condominium	Energy Saving/kWh/m2/ Year	Money Saving/Baht/ Year
1	107.74	506.38
800	86,198	405,104
1000	107,747.5	506,380

The value of 4.7 Baht/kWh refers to the rate of the Metropolitan Electricity Authority (MEA) [21] and the Provincial Electricity Authority (PEA) [22].

. These savings were derived primarily from the reduced cooling load due to the minimized heat gain and the reduced need for artificial lighting during the day.

While the initial cost of installing dynamic windows may be higher than that of traditional windows, the long-term savings in energy consumption make them a cost-effective solution. In addition to the direct financial savings, there are also indirect benefits, such as reduced carbon emissions and a lower environmental impact, which further contribute to the overall sustainability of dynamic window technologies. With the growing emphasis on green building standards and energy efficiency regulations, dynamic windows offer a practical solution for reducing energy consumption and operating costs in residential buildings across tropical regions.

In summary, dynamic window technologies offer significant benefits in terms of energy savings, ventilation, daylighting, and cost efficiency in

Table 11. Summary table: result overview.

Aspect	Dynamic Window	Traditional Window	Energy Savings
Energy Consumption	200.21 kWh/m2/year	203.50 kWh/m2/year	3.29 kWh/m2/year reduction
Cooling Load	14,128.58 kWh/month	14,495.02 kWh/month	366.44 kWh/month reduction
Cost Savings	506.38 baht/year/room	No savings	506.38 baht/year/room
Ventilation	Stack-effect, passive airflow	None	Consistent airflow, reduced AC use
Daylight Optimization	Integrated shading, reduced glare	Standard windows	Reduced need for artificial lighting

.

4.5.2. Life Cycle Cost Analysis

The lifecycle cost (TLC) analysis evaluates the long-term financial impact of dynamic windows compared to traditional windows in tropical condominium settings, incorporating installation, maintenance, and energy savings over a 37-year period [19]. With a discount rate of 5%, this analysis provides insights into the financial sustainability of each window type.

• Total Lifecycle Cost (TLC):
  Traditional Windows: The TLC for traditional windows is 15,000 baht, covering only the initial installation, as no maintenance or energy savings were included.
  Dynamic Windows: The TLC for dynamic windows totals 15,448 baht. This includes the initial cost of 21,000 baht, discounted maintenance expenses of 3063 baht, and discounted energy savings of 8615 baht. Despite a higher upfront cost, dynamic windows nearly balance out over their lifecycle due to energy efficiency;
• Payback Period: The payback period for dynamic windows is approximately 18.4 years. After this point, energy savings offset the initial investment, reinforcing the economic viability of dynamic windows in the long term;
• Net Savings After Payback: Following the payback period, dynamic windows generate annual savings of 326.38 baht, totaling approximately 6066 baht over the remaining 18.6 years. This long-term financial benefit underscores the sustainability of dynamic windows, making them a practical choice for energy-efficient building design in tropical climates;

In summary, while dynamic windows have a slightly higher lifecycle cost, they achieve payback within 18.4 years and provide additional financial savings of approximately 6066 baht throughout their remaining lifespan in

Table 12. Summary table: net savings after payback.

Window Type	Initial Cost (Baht)	Discounted Maintenance (Baht)	Discounted Energy Savings (Baht)	Total Lifecycle Cost (TLC) (Baht)	Payback Period (Years)	Net Savings Post- Payback (Baht)
Traditional Windows	15,000	-	-	15,000	-	-
Dynamic Windows	21,000	3063	8615	15,448	18.4	6066

. This analysis highlights the dynamic windows’ long-term economic benefits, making them a sustainable choice for energy-conscious designs in tropical climates.

5. Discussion

The results of this study emphasize the critical role of integrating passive and active window technologies to enhance energy efficiency in tropical condominiums. This section discusses the integration of systems, the challenges in adopting these technologies, and the broader sustainability impacts.

5.1. Integration of Passive and Active Systems

Dynamic window technologies effectively integrate both passive and active systems to achieve optimal energy efficiency. Passive elements, such as stack-effect ventilation, allow warm air to rise and exit the upper window openings, while cooler air enters through lower openings. This natural airflow reduces the need for mechanical ventilation and cooling systems during daytime hours. The active components, such as horizontal automated shading devices and Low-E glazing, adjust based on real-time sunlight intensity. These shading devices block direct sunlight during peak hours, preventing overheating, while Low-E glass adjusts its transparency to optimize daylighting. The combined passive and active elements create a balanced system that maximizes natural ventilation and daylight while minimizing solar heat gain and the need for air conditioning. The synergy between these passive and active technologies significantly lowers energy consumption, contributing to overall sustainability in condominiums.

5.2. Scalability Challenges and Solutions

Aluminum-framed dynamic windows offer scalability for both new builds and retrofits, particularly in tropical climates where corrosion resistance is essential [4]. Aluminum’s availability, durability, and affordability make it suitable for improving energy efficiency in existing structures without specialized labor or structural changes. Lightweight and modular, aluminum frames minimize disruption and reduce costs, making them ideal for older buildings aiming for energy-efficient upgrades.

For new constructions, standardized aluminum components like cantilevered sun shades and stack ventilation frames streamline installation and ensure compliance with local codes. Additionally, aluminum’s resistance to rust supports long-term sustainability, aligning with green building standards and promoting dynamic windows as a viable option for energy-conscious design. This scalability supports urban sustainability goals by enabling enhanced natural ventilation and reduced energy use across various building types.

5.3. Challenges and Strategies for Enhancing Adoption of Dynamic Windows

Despite the promising energy savings, there are notable challenges to the widespread adoption of dynamic window technologies in Thailand’s middle-class condominiums. The initial cost of installing these advanced systems is higher than traditional windows, which may deter developers from incorporating them into standard projects. Wen Hong et al. 2007 noted that energy-efficient components, such as dynamic windows, can raise the cost of construction, leading to higher purchase prices for residents [4]. Maintenance is another issue; the complexity of automated systems like electrochromic glass and motorized shutters requires regular upkeep, which may not be feasible for all buildings.

Market acceptance is another hurdle. Many residents and developers are unfamiliar with the benefits of dynamic windows, leading to a preference for conventional solutions. Public awareness campaigns and government incentives, such as tax rebates or energy-efficiency grants, are necessary to encourage adoption. Studies have shown that when these technologies are subsidized or incentivized, they become more attractive to both developers and homeowners [23,24].

To improve user adoption of dynamic windows, integrating user-friendly design features and effective training can enhance ease of use. Key design enhancements include intuitive interfaces, such as touchscreens or mobile apps, and preset modes (e.g., automatic, manual, energy saving) that simplify controls. Additionally, providing users with accessible training materials, like guides or video tutorials, can shorten the learning curve. Smart sensors with self-diagnostic capabilities can notify users of maintenance needs, increasing system reliability. Overall, these features support a more user-centric approach, making dynamic windows more approachable for residential and commercial users alike.

5.4. Broader Sustainability and Economic Impacts

Dynamic window technologies contribute to sustainable development by reducing energy consumption, enhancing occupant comfort, and supporting urban sustainability goals. In tropical climates, dynamic windows significantly lower cooling demand, reducing reliance on air conditioning and aligning with global sustainability initiatives like the United Nations’ Sustainable Development Goals (SDGs) [25], particularly Goal 11 for Sustainable Cities and Communities [26].

5.4.1. Environmental and Energy Efficiency Benefits

By lowering cooling loads, dynamic windows help mitigate the urban heat island effect and reduce greenhouse gas emissions. This aligns with Thailand’s Energy Efficiency Plan (EEP) 2015 [1], which aims to reduce national energy consumption. These technologies assist Thailand’s transition toward greener urban development, supporting goals to address climate change while meeting energy efficiency standards in buildings over 10,000 square meters.

5.4.2. Market Differentiation and Competitive Advantages

Dynamic windows enhance building value by offering automated shading and transparency adjustments, making condominiums more appealing to environmentally conscious residents. Studies show that eco-friendly buildings can achieve rental and sales premiums, increasing property value by up to 10% and potentially increasing occupancy rates by 3.5%. This advantage resonates with market demands for sustainable urban living, aligning with SDG 11 [23,24,25,26].

5.4.3. Economic Impact for Developers and Occupants

For building developers, dynamic windows offer long-term economic benefits by reducing operational costs. The life cycle cost analysis reveals energy savings of approximately 8615 baht over 37 years, with an 18.4-year payback period. After this, an additional 6066 baht in net savings is achieved. For occupants, dynamic windows provide adaptive temperature control, improving comfort and productivity, supporting both SDG 3 (Good Health and Well-being) and SDG 7 (Affordable and Clean Energy) [25].

5.4.4. Urban Resilience and Climate Action

By lowering building cooling requirements, dynamic windows alleviate strain on urban energy resources, contributing to urban climate resilience. This reduction in energy demand supports SDG 13 (Climate Action), integrating energy efficiency with urban sustainability [25].

Dynamic windows present both environmental and economic advantages that reinforce their role in sustainable urban development. Their ability to balance individual comfort with urban sustainability initiatives highlights their importance in future building designs for tropical regions, contributing to resilient and efficient urban environments aligned with global SDGs in

Table 13. Summary of economic and sustainable benefits of dynamic windows.

Category	Green Building Economic Benefits	Dynamic Windows Economic Analysis
For Building Developers	Higher occupancy rate by 3.5% and property value premium of up to 10% due to eco-friendly features [4].	Projected lifecycle energy savings of 8615 baht over 37 years, with a payback period of 18.4 years.
For Owners/Occupants	Potential reduction in water/energy consumption by up to 60% [4].	Enhanced comfort and productivity (+25%), with post-payback net savings of approximately 6066 baht across remaining years.
Sustainable Urban Impact	Supports reduced energy demand, and mitigates heat island effects [25].	Dynamic windows aid in achieving SDGs for sustainable urban development, particularly SDG 11 (Sustainable Cities) and SDG 13 (Climate Action) [25].

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6. Conclusions

This study demonstrates that dynamic window technologies can significantly enhance energy efficiency in tropical condominiums, such as those found in Thailand. By integrating passive design strategies like stack-effect ventilation and active technologies, such as automated shading and thermochromic glass, these windows offer a practical and scalable solution to reduce energy consumption. The findings highlight that dynamic windows can reduce energy use by 3.29 kWh/m² annually, equating to a 1.6% reduction. This translates into significant financial savings for condominium owners, with potential savings of 506.38 baht per room per year, or 506,380 baht for a 1000-unit condominium complex. The cost efficiency is further highlighted in the lifecycle cost analysis, where the payback period is approximately 18.4 years, followed by additional net savings of 6066 baht over the remaining lifespan. The adaptability of this technology extends to both new constructions and renovations, as aluminum-framed windows are widely compatible with existing structures and installation practices. The scalability of this technology is evident, as the majority of middle-class condominiums in Thailand, typically ranging between 30 and 35 square meters in size, can benefit from the energy savings provided by these systems. The combination of passive airflow, automated controls, and optimized daylighting reduces reliance on artificial lighting and air conditioning, two of the largest energy consumers in tropical climates. Further research is recommended to assess the long-term environmental impacts of dynamic windows, particularly in terms of reducing greenhouse gas emissions and improving occupant comfort. In addition, policy integration is crucial for promoting the widespread adoption of this technology. Government incentives, such as tax rebates or energy efficiency grants, could make the installation of dynamic windows more financially attractive for developers and homeowners. Exploring smart control systems that allow for real-time adjustments to window settings based on external conditions, through mobile applications or intelligent sensors, could further enhance the effectiveness and user-friendliness of dynamic windows.

In conclusion, dynamic window technologies provide a promising avenue for improving energy efficiency and sustainability in tropical urban developments. By integrating passive and active design elements, these windows contribute to the broader sustainability goals of reducing energy consumption and emissions, making them an essential component of future green building strategies.

7. Recommendations

Future studies on dynamic window technologies should focus on comprehensive lifecycle analysis to evaluate their long-term environmental and economic impacts. Such analysis would provide valuable insights into the durability, energy savings, and maintenance costs over time, helping to establish a more accurate cost–benefit ratio. Lifecycle analysis would also assess the embedded carbon emissions associated with the manufacturing, installation, and eventual disposal of these technologies, contributing to a more complete picture of their sustainability performance in tropical climates like Thailand. Another key area for future research is the improvement of automation systems within dynamic windows. Current systems rely on sensors and automated shading mechanisms, but there is potential to enhance adaptability through advanced control systems that respond more precisely to changing climate conditions. These could include integrating smart technologies, such as Internet of Things (IoT) sensors, which allow real-time adjustments based on weather patterns, occupant behavior, or energy usage goals. This would improve the user experience and further optimize energy savings, especially as climate change increases the variability of weather conditions in tropical regions [27,28].

Finally, policy frameworks and government incentives should be further explored to promote the widespread adoption of dynamic windows. Regulatory bodies could implement stricter energy efficiency standards or provide financial incentives to developers and homeowners who invest in these technologies. By encouraging adoption through policy and market-driven initiatives, dynamic windows could play a pivotal role in creating more energy-efficient and sustainable urban developments in tropical climates. These future implementations would solidify the role of dynamic windows in meeting both energy efficiency and environmental sustainability goals in urban condominiums.