Pruksa+ House

Residential Design Sustainable Design

Sustainable and energy-efficient homes are becoming an increasingly important worldwide. Sustainability is about “preserving natural resources for future generations without compromising current users essential right for the quality of life” (Brundtland Report, United Nations 1987). Considering architecture, such sustainability is based on a holistic approach, comprising expert knowledge and related disciplines to implement progressive building standards that help to protect our natural environment as well as maintain and support building occupant’s health and well-being.

The conviction and commitment to realizing sustainable design require not only the know-how and expertise of architects but the early corporation and integration of all necessary stakeholders such as experts and building owners. Unexpected Co. Ltd. is offering such sustainability-based cooperative work, helping building owners and developers to design, plan and realize ambitious and advanced, yet reasonable and economic, sustainable building projects.

The single-family house is a research project in cooperation with Real Estate Company Pruksa PLC, built and completed in 2016, it is located at the ‘The Plant Estique, Pattanakarn’. The project’s objective was to explore viable strategies for improving the energy efficiency of residential homes and to investigate sustainable solutions for future implementation. Recognizing its local context, the Pruksa+ house was developed in reference to an existing building type of the housing estate and by utilizing the companies advanced pre-cast construction technique.

To verify the quality of the building, a sustainability evaluation per the German assessment scheme for sustainable building (DGNB system) has been conducted. Achieving an overall assessment achievement of 81.5%, the Pruksa+ house was received the DGNB platinum award; it is the highest possible certification award to be received and the first one that was granted to a project in South East Asia.





The following examples of the realized ‘Pruksa+’ House demonstrate, how the sustainable thinking and practices were realized. In the following, a small selection of sustainable features are briefly described, including aging-friendly and barrier-free design, indoor air quality, water saving, and waste collection:

Floor Plan Quality

Improving the floor plan quality of building includes concerns regarding the appropriate amount of space and its inherent functions in relation to a number of occupants foreseen. This includes determining the size and amount of furniture and its required clearance spaces, but also the ability to properly furnish respective spaces, their possible flexible use, and rearrangement.

Age-friendly and barrier-free design

To improve the building design for elder generations and disabled, several barrier-free design and planning elements were included, significantly increasing the building utilization for these groups. The measures of improvement include sufficient dimensioning of corridor areas, clearances spaces of rooms, railings, and handlebars for sanitary objects, but also floor even access, ramps, and a stair lift in accordance with German standard regulations. 

Safety and Security

A home automation system was foreseen to combine lighting and cooling and ventilation control easily controllable. Further, the automation allows for accessing CCTV cameras within and outside the house. Fire safety was improved by the installation of smoke and heat detectors in the house.

Indoor Air Quality

Indoor air quality (IAQ) is based on improving and maintaining occupant’s health. It is achieved through sufficient fresh supply/air exchange, but also via materials that provide low content of volatile chemical compounds (VOC).

With improved airtightness of a building, sufficient fresh air supply and ventilation must be maintained. In the Pruksa+ house, the ventilation based concept foresees fresh air exchange is via natural and mechanical ventilation. Natural ventilation provides the owner with the option to supply fresh air when deemed necessary. Additionally, mechanical ventilation is realized through exhaust vents in the bathroom units, and via air-exchange vents that include a heat recovery and air filter system. The air vents are located in living and bedrooms and are activated according to usage, mostly in combination with the air conditioning system.

Building materials with low VOC content typically reduce the amount chemical compounds that are released by them into the air. Materials or building elements that are exposed to interior spaces are of concern. For the Pruksa+ house, these material have been scrutinized and selected according to their VOC content. A later VOC testing documented the improved Total VOC and Formaldehyde levels in the building.

Water Saving

Freshwater saving was realized by resorting to water armatures that enable low flow rates, capable of reducing the amount of fresh water supply by one-third. Wastewater saving was achieved via a gray water collection system that was collected from bathroom sinks and rainwater to be used for irrigation purposes.

Waste Collection

A waste collection and recycling concept was developed in reference to the prevalent waste disposal situation, where all household waste is collected unsorted and disposed of.

To reduce the overall amount of waste occurring in a household, it must be separated into components that allow for further use and/or recycling.  Accordingly, the waste disposal is divided into two parts: the disposal of non-recyclable household garbage managed by the housing estate and realized by metropolitan authority, and the separation and organization of recyclable household waste managed by the building owner.  

Respectively, non-recyclable waste is to be collected in the garbage bin that is allocated to the exterior wall of the property wall as originally foreseen by the housing estate planning. The garbage bin is accessible from both sides; thus, garbage truck workers can pick them from the adjacent street without accessing the property grounds.

Recyclable waste is separated as suggested by distinguishing into organic waste and collectible household waste organized into sections of papers, plastics, glass, and miscellaneous such as metals. The organic household waste is utilized for compost usage. The recyclable household waste is stored in the recycling area next to the parking, and picked by informal waste pickers upon the house owners request.


Energy-efficiency is a major contributor to the meaningful realization of sustainable homes and resource preservation. With homes capable of realizing ‘Net-Zero’ or ‘Energy-Plus’ capabilities, energy-efficient homes are able to meaningfully contribute to energy conservation.

Saving energy is a significant part of saving natural resources, as most of their consumption takes place during building operation. Improving the energy-efficiency of buildings offer financial benefits as well when employing long-term strategies. Typically, in the design and planning process, active and passive measures for reaching energy-efficiency are considered.

Passive measures are eliminating energy demand from the very beginning of the architectural design. Following the standpoint that any energy not used is energy saved, passive design measures scrutinize architectural design by emphasizing on design principles such as building type, shape, orientation, function, and form, but also common passive design principles of foreseeing building insulation, openings, airtightness, ventilation, and thermal breaks of the building surfaces. 

Active design measures ensure buildings’ energy-efficiency via technology implementation such as renewable energy utilization, innovative integration of cooling and heating, or appropriate techniques for fresh air supply and ventilation.

To achieve energy-efficient building performance for the Pruksa+ house, a number of passive and active measures were undertaken. Respectively, passive implementations mainly focus on improving building elements such as exterior walls, wall openings, and roof, which typically define the threshold between the indoor and outdoor climate. Among others, they encompass:

  • A compact building shape to reduce the building’s exterior surface area amount, minimizing the heat transfer into the building
  • A quality insulation of exterior walls, wall openings, and roof, further restricting to the conduction of heat into the building
  • The use of several shading applications, preventing  solar radiation onto exterior surface areas and insolation of direct sunlight into the building through its window areas
  • An airtight building construction, preventing uncontrolled outdoor air infiltration. 

In addition, the integration of advanced technologies was foreseen to further reduce the energy demand of the building. These active measures include the generation of renewable energy through photovoltaics (5 kW). Avoiding battery storage, the generated electricity is directly used to charge an ice storage instead. During the evening and nighttime hours, when a major amount of electricity is used for the air conditioning of the building, the alternative ice storage is coupled via heat/cold exchanger to cool the refrigerant of the fan coils. The automated building ventilation is also coupled to the fan coils. Providing a sufficient amount of air exchange to the rooms, it is integrating a heat/cold exchange between the air intake and exhaust. 

The described energy measures were verified through various simulations during the planning process, indicating that passive measures are able to reduce the buildings operative energy consumption up to 50 %. Another 25 % of energy usage reduction is achieved through the implementation of active measures.

Because the roof is capable of carrying photovoltaic panels up to a power generation of 12 kW, a later extension of the photovoltaic system can be foreseen when current government plans, allowing private homes to feed electricity to the public grid, are realized. The Pruksa + house will then be capable of performing as an ‘Energyplus’ house, adept at generating more renewable energy throughout the year than required to cover the buildings annual energy demand.


For the Pruksa+ house, sustainability measures have been realized by applying practical knowledge of architectural design for tropical climates. With the design implementation and support of the Pruksa+ house (a sustainable and energy efficient residential prototype), it has proven to realize sustainable buildings in tropical climates such as Thailand as architects and sustainable building consultants.


Bangkok, Thailand



Topic of Interest

Residential Design, Sustainable Design, Energy Efficiency

Project Size

190 sqm