Research Article
The Correlation between Floor Area and Design of Opening for Refurbishment Projects
in Affecting Building Energy Consumption
Radzi Ismail1*, Ha Chin Yee2,Khoo Terh Jing3, FazlielAswad Ibrahim4, Salman Riazi Mehdi Riazi5
1,2,5School of Housing, Building and Planning, Universiti Sains Malaysia, Pulau Pinang 3
Department of Quantity Surveying, Faculty of Built Environment, Tunku Abdul Rahman University College
4FacultyofCivil Engineering Technology, Universiti Malaysia Perlis *Corresponding author e-mail: radzi@usm.my
Article History:Received: 10 November 2020; Revised: 12 January 2021; Accepted: 27 January 2021; Published online: 05 April 2021
Abstract: Construction industry is well known as the major source of environmental issues while public awareness has
raised upon time due to significant impacts due environmental problems. Project refurbishment has raised as one of the solutions to reduce the environmental problems as it reuses and recycles existing building by carry out adequate renovation and refurbishment to make the old or abandoned building reusable again. However, there are consent on the factors such as the impacts of additional floor area and design of opening onto overall energy consumption in refurbished buildings.A qualitative method has been employed in this study where a total of 5 respondents who are working in Pulau Pinang refurbishment projects.From the results, design of opening is agreed as the main contributor to total energy consumption in refurbished building while factor of additional floor area merelygain agreement from respondents. This study has the novelty in the context of refurbishment project in Pulau Pinang asit can be a useful guideline to the designers or practitioners who are designing refurbishment projects for historical city such as Georgetown and Malacca.
Keyword:Refurbishment Project, Energy Consumption, Opening Design, Floor Area
1. Introduction
Refurbishment projectis one of alternative in producing the facilities to fulfil the new trend of demand. Shah Ali et al. (2009) have mentioned that the refurbishment projects United Kingdom have been grown rapidly in the last 40 years and the same phenomenahappened in Malaysia since year 2009 and this trend is showing increment every year. The refurbishment project can be understood as upgrading, carry out major renovations, alterations, conversions and modernization of an existing building that have been used for a certain time period(Cha et al., 2011).The refurbishment project is believed to be complex and less foreseeable in the construction industry as old building might have severe structure problems, mechanical and electrical problems that cannot be identified before major repair works are carried out (Rayers & Mansfield, 2001).
According to Building and Construction Authority (2014a) in Singapore, the refurbishment of a building can obtain about 20% of energy efficiency. Refurbishment works is a good contingency when the building has reach its critical stage where it fails to functioning and work efficiently(Shah Ali et al., 2009). Therefore, Gohardani and Björk (2012) have highlighted that the significant environmental, economic and social benefits of doing refurbishment instead of demolition.However, the refurbishment works are greatly affected by the building physical characteristic such as the deterioration of structure and the obsolescence of technology used(Shah Ali et al., 2009). Hence, an appropriate design should be producedbefore the commencement of refurbishment works(Kim & Park, 2018).
According to Kim and Park (2018), most of the current refurbishment projects are applying solutions at the end of the design phase where most of the alternatives approaches during refurbishment works are greatly limited.Hence, the design of the refurbishment is essentially important at the early stage to give more opportunities in exploring contingencies (Hannele et al., 2012). Besides the design issue, the floor area in a building is crucial importantas the larger the floor area the bigger the energy consumption need (Konstantinou & Knaack, 2011). Since the floor area will affect theenergy consumption, this factor should be considered in refurbishment project.
2. Literature Review
Kim and Park (2018) have highlighted the importance of planning the design in the early stage of refurbishment project while Konstantinou and Knaack (2011) stated the influence of floor area in energy consumption, these two factors should be linked to the refurbishment project where efficiency in building energy consumption can be achieved.
Crosbie et al. (2011)have identified the importance of correct decision making in the early design stage as refurbishment project has one main issue to be solved which is the high risk(Burton, 2012). However, by doing refurbishment on existing building can achieve sixty percent of operational cost savings by just investing only twenty percent more building construction cost in the construction phase(Flanagan & Jewell, 2005).
2.1 Floor area and energy consumption: no relationship
According to Huovila et al. (2013), the energy efficiency of a building will be affected by the occupancy density, occupancy levels and occupancy times as the energy performance will be high when lesser building space is needed by a certain amount of people. Besides, the smart technologies like automation system for the lighting and ventilation in a building will help in reduce the energy consumption as the smart system will control the electrical usage of the building.
According toDepecker et al. (2001), the energy consumption of a building is affected by the shape of building. The larger the external wall area, the higher the energy consumption of the building.Besides, German Building Code proved that energy-efficiency of a building is influenced by the shape of the building.Ourghi et al. (2007) havesuggested the application of relative compactness (RC) as a simplified analysis method to predict the total energy used for annual cooling that based on building shape.
Building shape considered as one of the reasons that affect the energy usage of building can be determined through the different shape of building like length, depth height, gradient and type of the building. According to Göksal and Özbalta (2002), the heat loss-gain of a building is relying on the external surface area that face towards the external environment.
Zeybek (2009) declared that the shape of the building will affect the energy performance especially in the area that have climates changes. The buildings that located in the cold climate area should be designed in compact form to reduce the heat loss from the building in order to increase the energy efficiency of the building while in hot-humid area, the building should be designed in long and thin formto maximize the ventilation and lightning of the building in order to reduce energy consumption.
2.2Floor area and energy consumption: positive relationship
There are researchers who proved that there is positive relationship between floor area and energy consumption. Floor area will affect the building energy consumption for refurbishment project. This is because the floor area used and the total amount of user in the building is affecting the energy efficiency of the building. In the early stage of design phase, the floor area and the space occupancy will be the preliminary element to be considered base on the purpose of the refurbishment building(Labeodan et al., 2015). Therefore, floor area is playing crucial role in affecting the space efficiency as the larger the floor area the harder to achieve space efficiency.
According to Hietanen (2009), floor area and the energy consumption of refurbishment building are directly correlated. By lowering the amount of people and the space heating energy consumption in the building, the energy efficiency of the building will be increased(Huovila et al., 2017). This can be applied in Malaysia as Malaysia’s weather is always humid and hot, air conditioning is a must in closed space. By implementing adequate floor area and air-cooling system will alleviate the energy consumption. Therefore, the space design and the layout of the building must plan well before the refurbishment of the building begin.
According to Huovila et al. (2013), smaller space will need lesser energy embodied in the buildings and require lower need for energy in heating and cooling the internal space. However, this statement does not deem to be right perfectly as when a given space is used more effectively, the more the space will consume energy. Thus, less energy efficiency in the building will be shown in kWh/m2.
2.3 The Effects of Design of Opening towards Energy Efficiency
From the literature, design of opening is agreed to have positive relationship with total energy consumption (Bayoumi, 2017; Ibrahim et al., 2018; Tahir et al., 2017; Hee et al., 2015).Opening is the major component of a building and it will affect the energy performance of a building and maintain the thermal comfort in the building(Nawi et al., 2019; Li et al., 2015; Wang & Greenberg, 2015). It has an important function towards a building as opening act as a media that connect the internal environment and external environment, ensure the air circulation and ventilation in the building,maintain the illumination in the room, andobtain the nature light into
the building (Cuce & Riffat, 2015; Huang et al., 2014). Opening is playing an important role in a building as it has the responsibility to reduce the room temperature in hot climate region (Jelle et al., 2012)and gain the solar heat om cold climate region(Hee et al., 2015).
According to the Glass and Glazing Federation, there are 40% of the solar heat can be gained into the building through the opening (Bahadori-Jahromi et al., 2017). Although air conditioning can cool down the temperature in a room but air conditioning requires more energy to operate and this will increase energy consumption of the building (Bahadori-Jahromi et al., 2017). Therefore, it is very important to increase the public awareness towards the global warming issue and control the solar transmission through opening in order to reduce the energy consumption as electrical appliances arehigh energy consumption appliance.
The position of sun will affect the heat gain and loss in a building. Therefore, the orientation of windows in a building is very important as it will affect the energy efficiency of a building. The larger the external wall surface the higher the heat gain and loss through the building, so a compact shape building is the best for energy saving(Raji et al., 2017). According to research of Raji et al. (2017), the cross shape and Z shape building have the better performance in energy saving as the heat gain of these two shapes of building is the least compared to other shape of building. So, it can be concluded that cross shape building and Z shape building have achieved the energy efficiency building.
Figure 1. The cross shape and Z shape Source: Raji et al. (2017)
Based on the study of Raji et al. (2017), in a temperate climate region, a window-to-wall ratio (WWR) between 20% to 30% gives highest energy efficiency for narrow and deep building plan as lesser heat can be transferred through the facade during hot and cold season.There are integrated thermal and daylighting simulations created to measure the energy efficiency ranges of the buildings with different windows-to-walls ratio (WWR).According to Kheiri and Arch (2013), a building with no shading system and low-performance facade that U values for windows and walls were 2.4W/m2K and 2.6W/m2K respectively will obtain maximum energy efficiency range of 20% to 32%. However, Goia et al. (2013) said that the building with external solar shading device and high-performance facade that U values for windows and walls were 0.7W/m2K and 0.15W/m2K respectively will reach a maximum energy efficiency range of 35% to 45%. This can be concluded that the building with different performance of façade and WWR value will affect the results ofenergy efficiency value. A building with larger windows will have higher energy efficiencywhile the more facade can resist on the thermal, the lower the impact of WWR on total energy used in the building.Besides, the energy consumption of a building will increase when the WWR values less than 20%(Raji et al., 2017). The maximum recommendation of WWR values in temperate climate is 60% as any value higher than 60% will cause 10% increment in energy consumption due to the additional heat loss from building facade.
Table 1. The summary of results from various authors
Author Summary of results
Raji et al. (2017) 20-30% of WWR give highest energy efficiency for narrow and deep building.
Kheiri and Arch (2013)
2.4W/m2K and 2.6W/m2K of U values obtain maximum energy efficiency range of 20% to 32% for building with no shading system and low-performance facade.
Goia et al. (2013) 0.7W/m2K and 0.15W/m2K of U values reach a maximum energy efficiency range of 35% to 45% for building with external solar shading device and high-performance facade.
The WWR ratio in tropical climateis higher than the ratio in temperate climate but lower than in sub-tropical climate. The WWR ratio for a deep plan building is 30-40% while the ratio for narrow plan building is 25-35%.
In tropical climate, the energy consumption of the building will be higher than in sub-tropical climate due to the higher WWR values. Besides, the indoor and outdoor temperature in temperate climate is lower than in tropical climate.So, in the tropical climate, buildings can have a wider range of WWR values compared to that in temperate regions. The effect is significant when low U value, solar heat gain glazing, and shading systems are used in the facade to control solar gain through external walls.
Table 2. The window-to-wall ratio for different climate and building plan
Climate WWR Ratio
Deep Plan Building Narrow Plan Building
Temperate climate 20-30% 20-30%
Sub-tropical climate 35-45% 30-40%
Tropical climate 30-40% 25-35%
Ways to Reduce Energy Consumption
It is impossible to have a solution that can ensure energy efficient in every kind of building (S.Balamurugan ET AL., 2015). This is because there are lots of reasons that affect the energy efficiency of buildings such as the location of the building, system used, function of the building and materials used. Therefore, an effective approach is needed to resolve the problem of energy consumption in a building. The following are the ways that can reduce energy consumption of building:
i. Upgrade to LED lighting
LED (light-emitting-diodes) light is a semiconductor equipment that produce light. By using LED lighting, the energy efficiency will be improved compare to using incandescent and fluorescent lighting devices. This is due to the LED lighting only require low power to operate and most of the LED light bulb can operate by using battery. Besides, LED lighting devices are also high efficiency because it only requires minimal heat production to provide lighting to a building.This can help in reducing the usage of electric power supply and save the energy.
ii. Upgrade HVAC system
HVAC (heating, ventilating and air conditioning) system is using to provide fresh air and maintain the air quality and comfortable environment in a building.This system can be upgraded to maximize the energy efficiency level and improve the overall air quality in the building. During design stage of refurbishment project, a proper insulation must be implemented to ensure the heating and cooling systeminside the building at the most efficient level.
HVAC system can also upgrade by choosing the energy-star rate equipmentto increase energy efficiency of the building and save energy and money. This is because the energy-star rate equipmenthas high efficiency in heating and cooling system, water protection system, complete thermal enclosure system and efficient lighting and appliances. By using the energy-rate equipment, the greenhouse gas emissions and other pollutants can be reduced and provide a high quality of air and comfortable environment for the people in the building.
Besides, the heating and cooling system can also implement independently in each rooms of the building. The temperature of each room can be controlled easily by using the building energy management system rather than single-point censor. Therefore, the energy will not be wasted when there is no one inside the room.
iii. Install Smart Plugs
Smart plugs are used to control the energy usage of electrical appliances in a building. Smart plugs can be installed in a refurbishment project to help in increasing energy efficiency and save the energy usage. This is because smart plugs can set a scheduled time to control the energy appliances so the appliances will switch on and start to work on the time set while switch off when it is not in use.
iv. Energy-efficient Windows
Energy-efficient windows are energy saving windows that used to prevent the loss of heated and cooled air from the building. This is because the energy-efficient windows have increased the insulation so this can reduce the energy usage in the building and increase the comfortable level in the building. By installing the energy-efficient windows, the refurbishment building can be eco-friendlier as the carbon footprint will be offsetting.
Low-E window coatings can also be used to increase the energy efficiency of a refurbishment project. The coating can help in control the room temperature to keep cooler in summer and warmer in winter. This coating is also last longer from being scratch off as it applied inside the glass and it is very ease to take care that do not require any special cleaning for the window to provide protection to the furniture inside the building from the UV light.
Besides, solar window films can be used in the refurbishment project as it can help in control the light and heat from the sun in order to improve the room comfort. Solar window films have a better insulating compare to the normal window and it can absorb and reradiate the sunlight to reduce the temperature in the room. This can help in reducing the energy usage of the house and reduce glare of furniture because it prevents the excess heat and fading of the UV rays from penetrating through the window.
3. Research Methodology
This research is using semi-structured interview method that lasting each between 30 to 60 minutes to collect the data needed. Face-to-face interview were conducted with the managers who have involved in the building refurbishment projects in Pulau Pinang. Five corporates of different sizes were selected,and the interviews were conducted with the project managers of the refurbishment projects to get the feedback on the developed list of inquiries.The selected project managers have suggested a few changes in the list of the identified inquiries such as the professional names of the inquiry items and new inquiry that appropriate to be added into the developed list.
The purpose of interview is to capture the opinion of respondents towards the correlation between floor area and design of opening for refurbishment projects in effecting building energy consumption. These five respondents were interviewed to understand the correlation between floor area and design of opening for refurbishment projects in effecting building energy consumption. The interview sessions end when the information repetition and ongoing verification of the understanding during data collection indicated that the research had reached saturation. The data collected will be analysed by using content analysis as it is useful to analyse the presence, meanings and relationships of data obtained (Dellinger & Leech, 2007). Besides, there are other researchers like Hwang et al. (2015), Lund et al. (2016) and Masrom et al. (2017) who also complete their researches by using this method.
4. Results and Discussion
The semi-structured interview was conducted with five respondents from construction company which have the experience in refurbishment project. The following shows the results of the interviews.
4.1 Respondents’ Details Table 3. Respondents’ Details
Respondent Working Experience Position
R1 5 years Site Supervisor
R2 10 years Project Manager
R3 7 years Site Supervisor
R4 3 years Quantity Surveyor
R5 10 years Contract Manager
The table 3 shows the respondents details. The respondents that chosen for the interview are involved in refurbishment project, so their opinion and information given are precious and useful to this study.
4.2 Purpose and Factor of Choosing Refurbishing Building Table 4. Purpose of Refurbishing Building
Respondent Purpose
R1 Client requirement
To avoid heritage building from being abandoned
Commercial profit
R2 Renovate abandoned building and meet the requirement of end user
R4 Stay competitive and attractive to meet the demand of public
Generate higher rental revenues
R5 To avoid the existing building from being wasted
Table 4 shows that the purpose of refurbishing building that handle by respondents’ company. Most of the respondents mentioned that the purpose of their companiescarries out refurbishment project are to prevent the existing building from being wasted and become abandoned building. Besides, some of the respondents highlight that refurbishing existing building is to stay competitive and attractive to meet the requirement of end user and public. There are also respondents mentioned that their company doing refurbishment project is due to the client requirement and to generate higher rental revenues.
Table 5. Factor Choosing Project Refurbishment
Respondent Factor
R1 The heritage building in Penang area cannot be demolished R2 Land price in Penang area is too high
Restriction from state regulations and land price R3 There are limited vacant land for new development R4 The demolishing cost is too high
Refurbishment project takes shorter time
R5 Limited land and narrow space to put materials and machineries
Shorter construction period
According to the table 5, most of the respondents’ company will choose project refurbishment instead of constructing new building is due to the reason of the limited land in Penang area and the heritage building in Penang cannot be demolished. Therefore, their company choose to refurbish the existing building to protect the building from being destroyed or abandoned. Since Georgetown as the heart of the pearl of the orient, by refurbishing the buildings, Georgetowncan be more attractivewith the brighten ofmodern and classical renovationdue to its historical natures and characteristics which merge within a modern city. In addition, respondents also declared that the vacant land price in Penang area is too high so refurbishment project treated as priority choice. Besides, refurbishment project takes shorter time compared to new development project. Therefore, respondents’ company will choose refurbishment project instead of constructing new building.
4.3 Opinion of Respondents towards Factors that Affect Energy Efficiency
Based on the interviews, two respondents (R1 and R3) said that there is no relationship between the floor area and energy efficiency. “The energy consumption is affected by the requirement of the users. If users want to create a comfortable environment such as refreshing and cool temperature and bright environment, then the energy consumption will be higher due to the high usage of energy appliances in the building.” R1 and R3 said.Besides, the respondents also mentioned that the energy usage is depending on the function of the building. For example,
In contrast, three respondents (R2, R4 and R5) pointed out that increase of floor area will affect the energy efficiency of a building. “The larger the space of the building, the larger the usage of electricity. A building with large space will increase the energy consumption of the building as it need large amount of energy usage to maintain the comfortable level in the building” (R2, R4 and R5).Moreover, the respondents also mentioned that energy efficiency affected by the size of opening and orientation of building. According to their opinion,if the opening in a building is too large, the natural light can import into the building easily. However, it will cause the temperature in the building high and the electrical appliances like fans and air conditioning will be needed to cool down the indoor temperature. This led to the increment of the energy consumption of a building.
In addition, the respondents also declared that the electrical appliances used will also affect the energy efficiency of the building. “There are a lot of power-saving appliances to reduce the energy usage. For example, there are many 5-stars electrical appliances produced in the market and these appliances can reduce electricity consumption and reduce carbon footprint from electricity generation. Smart system can also install in building to prevent waste of power when there is no user in the room” (R3 and R5).
On the other hand, all the respondents believed that design of opening will affect the energy consumption of refurbishment project.“Our project is maximizing the natural light harvesting, the design, size and number are significantly impact the energy consumption of our building. Our building shape is a sharp triangle where both
sides of the buildings can harvest natural light easily. Therefore, the rooms in our building are purposely designed to harvest the natural light as much as they can. Furthermore, several holes are made on the roof slabs to transfer the natural light to the corridor on each floor. These have greatly reduced the need of artificial light in the rooms and building” (R2). According to respondent 2, the design of opening can help to capture the sunlight into the building in order to reduce the frequency of turn on the light in the building.
Besides, the respondents also stated that the opening with double glazing or triple glazing can increase the energy efficiency as the it can reduce the heat transfer into building. This can reduce the energy used in the building and increase the energy efficiency. However, the opening should not be too large as it will absorb most of the heat and raise the indoor temperature as heat from sunlight can easily go through large opening. This further justify the fact of design of opening significantly related to energy consumption in refurbished buildings.
4.4 Solution to Increase Energy Efficiency of Refurbishment Building
Theopinion of respondents towards solution to increase energy efficiency of refurbishment building has been collected through the interview session. The natural resources in the world are reducing year by year, so action should be taken to reduce the energy usage in order to increase the energy efficiency of building. There are two respondents mentioned that building automation system (BAS) can be installed to control and monitor the usage of energy. “Building automation system (BAS) combines all the electrical appliances like HVAC system, auto close water tap, sensor motion detection lighting, create usage of natural lighting that operate in the building. It can help to control the electrical usage such as the HVAC system and lightning will turn off automatically when there is no any user in the space. This smart system can help to control the building indoor environment and the systems should be ranbased on occupancy rate and energy demand” (R4 and R5).
Besides, there are three respondents mentioned that the design and material of opening are one of the solutions that can increase the energy efficiency of the building.
“The type of the glazing used for openings will affect the room temperature significantly in order to affect the energy consumption in the room. Glazing that capable to filter out temperature from sunlight is recommended for air-conditioning room as air conditioning system will consume great amount of electricity to maintain comfortable room temperature” (R2 and R3).
“Malaysia's climate is categorized as equatorial, being hot and humid throughout the year. Therefore, the opening is essentially important to improve the energy efficiency when the room temperature can maintain at refreshing level” (R5).
In addition, there are respondents suggested to install the thermal insulation sheets and solar panel to reduce the energy usage of the building. Thermal insulation can prevent the heat transfer from outside into the room so the indoor temperature will not be too high and reduce the usage of electrical appliances like fans and air conditioning. Respondents also declared that although the solar panels are expensive, but it is a long-term benefits device. “Solar power provides renewable energy and this can prevent the excessive usage of the natural resources. By installing solar panel, the electricity can be controlled from overusing in order to save the utility bill of the building” (R1).
5. Conclusion
This study investigates the correlation between floor area and design of opening for refurbishment projects in affecting building energy consumption within Malaysia where these two factors are agreed by majority of the respondents in affecting energy consumption.The findings found that most of the respondents think that there is significant correlation between floor area and design of opening onto energy consumption in refurbishment of project, but floor area gain lesser recognition within the interviewed respondents.This is due to the limited and constraint space of respondents’ project that disallow them to consider the possible additional floor area that might impact the energy consumption where they do not need to consider the factor of additional floor area that might cause higher energy consumption.
Next, indeed, the design of opening is agreed as consensus which will affect the energy consumption in project refurbishment especially in Malaysia tropical climate. Majority of the respondents agreed that the design of opening in the building will affect the overall energy consumption significantly.According toRaji et al. (2017), the design of opening in tropical climate region should be widerto harvest more natural light instead of using artificial lighting.Therefore, the design of opening in refurbishment project as one of the factors that will affect
the consumption of electric appliances’ consumption is in line with other recent findings such asYang et al. (2015), He et al. (2019)and Yaşar and Kalfa (2012)which make this study findings more credible and reliable.
6. Acknowledgement
The authors would like to express the gratitude towards the financial support from the short-term research grant 304/PPBGN/6316231.
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