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K House


Hanoi, Vietnam

Type of Building: Residential Building
New / Refurbished: New
Status: Operational Stage
Year of construction: 2011
Gross Floor Area: 372 sq.m

The K house is a typical Hanoi tube house that is 25m long by 4.5m wide. It has 1 open façade and accommodates 5 members of a 3-generation family. The 4-storey house has inherent advantages due to its Southeast orientated main façade. The spaces have been designed by the architect to optimize its natural advantages to bring the best natural living opportunities for the dwellers. An open split-level space and large skylight account for over a quarter of the floor area with a large window to wall ratio combined with a large outdoor balcony creates a green buffer space, has created a unique living environment.

The total construction cost including interior finish came to 1.7 billion VND, equivalent to 4.5 million/m2 in 2011.

Design: Pace Architect
Images: Nham Chi Kien


KTS. Nham Chi Kien




Pace Architecture

(84 4) 3710 1575






The site


The house is located in Hanoi, which is subject to monsoonal tropical hot and humid climate zones with a cold winter. This climate zone is part of the Northern delta according to QCVN02:2009 Building Code. Hanoi has an average temperature of 23.6oC, where the hottest month averages 29.2oC, the coldest 16.4oC, with an average relative humidity of 82%.

The site is typical for long but narrow tube houses found in many in big cities in Vietnam, it is 25m long by 4.6m wide with the main façade orientated Southeast, slightly more inclined to the East. This is considered a good orientation as it takes advantage of the Southeast cooling breezes during the hot months and avoids the cold Northeast winds in winter.

Sun path diagram

Solar radiation impacts the building generally in a good way. In winter months from November to February, the sun stays longer to the South, which is also the house’s main orientation, and receives more direct solar heating. Meanwhile, in summer months from April to August, especially in June, the main façade is not as exposed to direct solar radiation.

Ventilation design

The house is located in a hot humid tropical climate zone with a cold winter. The design strategy for this house, in this kind of climate was: to be open-able when necessary (in hot humid summers) and closed tight in colder weather (during winter). The architect used a number of design solutions to utilise this strategy and these are outlined below

  • By providing split-level space as opposed to atrium space, facilitates natural ventilation to more than one floor. With large interior spaces as found in the K-House, split-level space provides a maximum ventilation solution to all living spaces.
  • Two skylights are located in the house, one in the middle and a smaller one to the back.
  • The two skylights have operable shutters to the side and to the top. These shutters can be closed in winter and open in summer when needed.
  • The skylight is also designed to facilitate natural ventilation, it is shaped to funnel the Southeast prevailing wind to enter the building.
    bieu do gio 2
  • Large windows make up more than 66% of the wall area.
  • The boundary wall is reduced to interconnect spaces.
    Góc nhìn từ bếp ra
    Góc nhìn từ phòng ngu ra giếng trời 1
  • The stair is made up of cantilevered timber to encourage air ventilation, as opposed to a solid enclosed stair. This also improves natural lighting into the house.
    15. Góc nhìn qua các bậc thang

Lighting design

  • The large skylights allow for every room to be full of natural light.
    bo tri khong gian gieng troi
20% of the building area is skylight
38% of the building area is skylight, stairs and corridor

The K-House case study shows that large skylights can contribute to the environmental living quality for the house dwellers by creating spaces that are full of natural light and are green, ensuring better health and happiness for children and the elderly in crowded and polluted cities.
02. Góc nhìn từ sảnh vào bếp

  • Additionally there are large clear windows in the façade that creates a house full of light.
    Phòng sinh hoat chung
The window to wall ratio is 66% to the main façade with a with a large balcony 2m deep.
Window to wall ratio is 34.5% to the façade facing the interior skylight.
  • Clear glazed balcony and stair railings allow for light penetration
  • Boundary walls were reduced
    08. Góc nhìn từ phòng ngủ tầng 2 ra thông tầng
  • Automatic blinds have been installed to the skylights to actively control the amount of sunlight.Rèm chắn nắng giếng trời


Over 80% of the area has a natural lighting luminance of more than 600 lux (Daylight factor is over 5%) according to 12000lux luminance standard in Hanoi. This is the luminance intensity to ensure the comfort for basic activities for the house dwellers.


  • Light analysis shows that the K-House exceeds the standard and gets at least 3 points in Lotus Residential pilot certification.
    phan tich anh sang

Shading and Insulation

  • The building envelope uses large windows combined with a large 1.95m deep balcony to create a garden which acts as an insulating buffer space for the building.
  • On the third floor, a timber frame oriented to the East allows direct sunlight to radiate deep into the house in winter months from December to March, meanwhile in summer the timber frame limits direct sunlight penetration.
    Mat tiền nhà
  • In order to illustrate how the balcony depth impacts shading and reduces radiation to surfaces below, a comparison between 1.95m deep balcony combined with a shading wood frame vs. a standalone 0.9m deep balcony has been tested. The results shows that the total hours that surfaces are exposed to direct sunlight in summer is remarkably reduced as indicated below:
The effect of solar radiation on the house with 0.9m long balcony in August The effect of solar radiation on the house with 1.95m long balcony and louvre system in August (K House)
The effect of solar radiation on the house with 0.9m long balcony in September The effect of solar radiation on the house with 1.95m long balcony and louvre system in September (K House)
The effect of solar radiation on the house with 0.9m long balcony in June The effect of solar radiation on the house with 1.95m long balcony and louvre system in May (K House)

According to the above analysis, in the case of the 0.9m deep balcony in June, August and September, the façade is still exposed to direct radiation for 9 to 11 hours respectively. Meanwhile, in case of the 1.95m deep balcony, the main façade is almost completely shaded for those same times or is exposed only on the second floor for 9h in September.

Also, according to the QCVN 02: 2009/BXD (Vietnam Building Code Natural Physical & Climatic Data for Construction), direct radiation intensity to the East and Southeast of the building, from April to September, reaches a maximum between 8 and 9 hours producing up to 700 W/m2. Therefore, 2m deep balcony and shading frame greatly reduces the direct radiation intensity to the façade and assists in energy saving because it provides more shading, creating a cooler house compared to what shading a 0.9m deep balcony would provide.

  • The stairs and auxiliary spaces are arranged in such a way so that the rooms nearby the main façade avoid Western sunlight that would be directly radiated through the skylight to the building, these spaces can be well-insulated from the heat in summer.

12 pm



animate shadows -1

Green space

The large skylight also increases the quality of the green spaces for the building by locating the green balcony near the skylight. The large skylight ensures sunlight for the vegetation to grow healthily.

100% of the living space have views to the green space.

Mat cat chung toa nha

Góc nhìn từ tầng 4 xuống
Góc nhìn từ phòng ngu ra giếng trời 1

This creates a pleasant outlook with plenty of green and natural sunshine for the occupants.

The green balcony located by the skylight has a very simple structure, constructed to support specific plant species that need less sunlight and water, such as Japanese bamboo and Japanese spinach.


0 0 1912 16 July, 2014 July 16, 2014
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