Purpose: Refurbishing houses is considered a key measure to improve the energy efficiency of the built environment. However, little is known about the implementation and outcome of housing renovation for energy upgrades in the Vietnamese practice. The purpose of this paper is to investigate the energy performance of the current housing stock in Vietnam and the potential to reduce energy use in households. Design/methodology/approach: The paper is based on a survey with 153 respondents in three major climatic regions of Vietnam. The survey focusses on building characteristics, environmental performance, energy performance and refurbishment activities. Data collected from the survey were statistically analysed to give insight into the current performance of the housing stock and its energy saving potential. Findings: This paper concludes that building design and construction, particularly the building envelope, have a significant influence on the occupants’ comfort. However, the energy consumption in houses is not statistically associated with building design and indoor environment. It is suggested that financial status and occupants’ behaviour currently have a strong influence on the household energy use. The survey also showed that refurbishment improves the housing performance, especially if improving the indoor environment was one of the drivers. Originality/value: There are very few studies on energy use in households in Vietnam, especially with regards to actual energy consumption. This paper brings insights into the actual energy consumption and reveals the “performance gap” in Vietnamese housing stock.@en

Traditional architecture has often applied greenery in the design to improve the thermal performance of indoor spaces. Such a bioclimatic approach is not often seen in the contemporary tube houses of Vietnam. Vietnamese architects recently started to focus more on greenery solutions for housing projects. However, the quantitative effects of plants on the building performance has not yet been investigated in Vietnam. This paper reports on an experiment to quantify the benefits of a vertical greening system for thermal performance and energy saving. A typical tube house in Hanoi was selected and two similar rooms were monitored during July and August, 2018. One of the rooms’ façades was covered by the climbing plant Bougainvillea. Outdoor and indoor temperature and energy for air-conditioning were measured for the two rooms to quantify the effect of the greenery on the existing aluminium shading device and a bare window. Results for the green façade showed that the difference between outdoor and indoor temperature can be as high as 8°C. In addition, the climbing plants helped to reduce the indoor temperature by around 1°C and thus cooling energy was saved by up to 35%.@en

Vietnam has made a lot of significant developments in both economic and social fields since the transition from a centrally planned to the market-oriented economy in 1986. Along with the growth of the country, the energy sector, which accounts for one-fourth of the national foreign earnings, plays an important role. In order to continue contributing to the sustainable development of Vietnam, the energy sector has to tackle the problems of ensuring adequate energy supply and minimising energy-related environment impacts. In building sector, a newly constructed building has more potential to achieve better energy performance than a refurbished project, which is limited by unchangeable factors on the existing site. However, the importance of the existing building should not be ignored due to the fact that the number of existing buildings is outweigh the number of possible new buildings added to the market annually. Although refurbishment activities are being carried out regularly in Vietnam, little effort was recognised to improve the energy performance of the building. One of the reasons is that the contemporary construction methods in Vietnam are still quite simple and do not integrate energy efficiency measures. Sustainable and energy-efficient housing was not just recently recognised and concerned in Vietnam. However, there is still lack of research in this specific field. This research aims to develop a design strategy for housing refurbishment projects in Vietnam, in order to achieve better energy performance. The approach should be systematic and holistic, addressing all relevant issues in the current housing stock of Vietnam. It is expected to be used to help architects in decision making in the early design stage and to help state agencies to set guidelines and regulations for future housing of Vietnam. This led to the main research question to be answer in this thesis. What are the design strategies for energy efficiency in Vietnam housing and how should they be integrated in an existing house as well as in a new built house?@en

Green Architecture for Sustainable Communities (GASC) was a joint event organised by Dutch and Vietnamese universities with the aim of boosting sustainable development in the built environment of Vietnam. As a key activity of the event, the international student design workshop focused on renovation of typical Vietnamese row houses – aiming towards sustainable and energy efficient homes. This study reports an evaluation of the student workshop based on a post-workshop questionnaire and the outcomes of the student groups. Results showed that most activities were successful in transferring sustainable knowledge to the students. The students were capable of learning sustainable theory, analysing suitable design strategies in the specific cases and applying that knowledge into the design proposals. Students learned more about bioclimatic designs and related topics such as daylight, natural ventilation, indoor comfort and greenery. Sustainable aspects of energy efficiency and water usage were also of great interest. The student selection process was the main issue for this workshop. For future events, more involvement of architects with practice is recommended.@en

The housing stock in Vietnam faces the challenge of becoming sustainable,provide a healthy living environment and reduce its energy consumption. The challenge lies not only in new buildings but also in existing houses. Nevertheless, little is known whether the new tube houses, the most dominant housing typology in Vietnam, can be renovated to offer adequate living conditions for the occupants, can tackle the issue of energy shortage, and can adapt to climate change. This paper introduces the potential of refurbishment design for energy efficiency. Although both passive and active approaches are encouraged, traditional bioclimatic design strategies, including solar control, natural ventilation and thermal insulation,are more popular because of their low cost and high efficiency. This paper concludes that solar energy has large potential in Vietnam because it can be used passively in sun space or actively in photovoltaics and solar thermal collectors. However, as these refurbishment measures require investments and careful design, the actual benefit in Vietnamese context has not yet been verified.@en

This paper investigated the energy upgrade potentials of different facade refurbishment options in tube houses of Vietnam. A calibrated Design Builder model was created to simulate energy performance of different cases. Vietnamese technical regulation of energy efficiency building and Dutch standards were the two main guidelines for selection of refurbishing measures. The simulation results showed that applying Vietnamese technical regulation can save up to 9% of energy for heating and cooling. More interestingly, highly insulated facade that followed Dutch standards led to much more favourable results of 21% reduction in air conditioner consumption. It is worth to note that such improvement was by far only achieved with a night-time operation of air-conditioner, as how the system was working in the reference house. Shading devices were also tested on a southwest facade window. Horizontal overhang had very limited benefit of less than 6% reduction in cooling energy. An external blind could save up to 12.6% of cooling energy. However, as all three shading types had a negative effect in heating season, the maximum annual saving was only 7%.@en

In Vietnam, the history of cities can easily be seen through their urban patterns, landscapes and housing typologies. Most recently, the economic reform in 1986 has resulted in huge impact on the Vietnamese society. The rapid economic growth and privatisation of the market has resulted in the appearance and significant development of the “new tube house” which soon became the most dominant housing type in Vietnam. Hanoi, the capital city of Vietnam, has a long history and also is very rich in architectural styles and typologies which are reflected in its urban pattern. However, there is no actual clear boundary in urban scale as the new tube houses are scattered all over the city and they are adapted differently to the contexts. This paper aims to investigate how the traditional urban tube houses in Hanoi transformed into the new tube house and, on the other hand, present the results of a survey conducted in Vietnam on how these houses respond to the Vietnam local climate and perform in terms of energy consumption.@en