The Role of Climate and Natural Energy in Iranian Traditional Architecture

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					Proceedings of the Regional Engineering Postgraduate Conference 2009
20-21 October 2009

         The Role of Climate and Natural Energy in Iranian Traditional Architecture

                                    Ar. Mastor Surat, Yahya Lawaf Pour
                                          Department of Architecture
                                 Faculty of Engineering and Built Environment
                                        Universiti Kebangsaan Malaysia
                                    43600 UKM Bangi, Selangor, Malaysia


         Environmental and natural phenomena play a very significant role in laying the region's
interrelated environmental, cultural, economic and social infrastructures.
         Iranian traditional architecture is constructed according to the specific climatic conditions and
differs with those built in other climates. Due to lack of access to modern heating and cooling equipment
in the past the architects were obliged to rely on natural energies to render the inside condition of the
buildings pleasant.
         In the past, without modern facilities, it was only the intelligent architecture of the buildings that
enabled people to tolerate the hot summer and cold winter.
          This paper concentrates on the results of sustainability caused by climatic elements in Iranian
traditional architecture. In a vast country such as Iran, with different climatic zones, traditional builders
have presented a series of logical solutions for human comfort.
         The aim of this research is to demonstrate how traditional architecture of Iran was appropriate
with climate conditions and environmental sustainable.
         At first, this paper classifies the climate condition in Iran then the principles of traditional
architecture will be explained according to characteristics of each climate conditions. The point of this
study is to investigate into the traditional building’s elements such as roof, wall, window, wind catcher,
court yards, sabat, building materials and etc.

Keywords: natural energy, climate conditions, Iranian traditional architecture, architectural elements.


         Vernacular architecture around the world is impressively rich with ingenious techniques early
dwellers used to protect themselves from the diverse weather conditions they were subject to.
When human being chose “Iran” as his dwelling place since many generations before, he began
constructing it. Then he encountered with various climates, therefore he tried to struggle with
environmental conditions, and create suitable internal spaces, and initiated different constructing methods
to adapt to the environment. Because of different climates in Iran, there are different building systems.
There are also valuable experiences in the field of designing, building and choosing of materials for
traditional buildings, aimed at struggling with environment conditions. Using local material, with respect
to their stability and resistance toward heavy load and pressures, heat, cold and also rain and snowfalls are
the factors that affect the appearances of traditional architecture in Iran. In Iranian traditional architecture,
the buildings are constructed according to the geographical location. And according to the position of the
ceiling, there are some needs for decreasing the space, which is under the direct radiation of sunlight,
choosing appropriate materials, constructing shades in each areas, walls, ventilation-shaft, basements,
central yards, shelters with expanded shadows, windows facing sun, constructing reservoir etc. These
factors make buildings struggle with such external matters in such a way that the best internal space will
be created without using the complex set of energy and pollutant systems. In another word, the past
generations have known about the rules and using sun systems and have applied it all.
         Great examples of well-thought vernacular architecture are located in Iranian plateau where a hot
-arid and desert climate zone prevails. This climate condition is probably a good example of extreme
weather conditions and studying the architectural techniques that allows the creation of independent
microclimates in these regions is worth exploring. Some of these traditional techniques are being slowly
rediscovered today and slowly applied to modern forms of architecture. However, sustainable features in
general and passive climate control in particular, even though newly rediscovered, are starting to limit the
architectural expression of the buildings.
         This case study explores the use of passive heating and cooling traditional Iranian houses. These
studies unearth impressive techniques and further studies of vernacular architecture would be inspiration
to the modern sustainable movement.


         The spatial characteristics of traditional Iranian houses reflect natural, geographical, and cultural
needs. The buildings in Iran are constructed according to the specific climatic conditions and natural
energy sources. In a vast country such as Iran, with different climatic zone, traditional builders have
presented a series of logical solutions for human comfort. Iran is basically divided into 4 main climate
regions 1.Hot- dry climate (central plateau) 2.Hot-humid climate (south beaches), 3.Cold climate (West
Mountains), 4.mild-humid climate (Caspian beaches) Each climate has its own characteristics and
suitable solution to provide human comfort by using the local materials and natural energy.

2.1   Natural Energy in Vernacular Architecture According to the Character of the Climate
      and Region

(a)     Hot-dry and hot-humid climate :( in this chapter these two climates will be compared)

    An important aspect of the traditional Iranian house is its adaptation to the harsh climate of the central
parts of the country. Notable climatic problems are harsh sunlight and temperature in the summer; diurnal
fluctuations of temperature; low humidity; limited water supplies; and dusty, sandy winds. In areas of Iran
with a hot and arid climate, special traditional designs found solutions to these problems. People living in
hot regions only relied on the natural source of energy to ventilate and cool their houses. System and
equipment by which wind is used for ventilation were, therefore, considered as ways and means of
providing comfort and easy life in buildings. Elements such as wind catcher, central court yard, Sabat or
spaces such as hozkhaneh and water reservoir in vernacular architectural planning where very popular in
Iranian old cities planning in hot regions. The local materials such as mud brick, braked brick, mud
mortar and wooden beam for ceiling were commonly used in belongings of hot-dry and hot humid

    Wind is one of the important elements for studying the climate. One of its important users is the
provision of comfort in hot region. This is because the wind current creates a difference in pressure on the
exterior walls that has an effect on the natural ventilation and interior air temperature of a building. For
architects, the wind is an important factor in the design of a building. They consider the wind's effect on
the thermal comfort through convection or ventilation and the penetration of air in interior spaces.
Wind has been given much attention in urban
design, and in particular in cities with hot weather.
The effect of the wind on building forms is
recognized through the use of formal features such
as wind tower which provides for the best use of
the wind for the comfort of the occupant.
     Wind tower (fig.1) is a key element in
traditional architecture of Iran. It is seen in
settlements in hot, hot-dry and hot-humid climates.
They look like big chimneys in the sky line of
ancient cities of Iran. They are vertical shafts with
vents on top to lead desired wind to the interior
spaces and provide thermal comfort. This
architectural element shows the compatibility of
architectural design with natural environment. It
conserves energy and functions on the basis of Figure 1: type of wind-catcher
sustainability principles.
    The tower head may have vents on one, two or
four sides that face the predominant wind direction
to accommodate wind in suitable directions. Wind
towers are often described by the number of
directions in which they face; such as one
directional, two directional, four directional, and
eight directional. The construction materials used
for wind towers depend on climate. The choice of
materials is made to ensure that the wind tower
operates effectively as a passive cooling system.
Wind towers in hot dry climate (fig.2) are built
either of mud brick or more commonly of baked
brick covered with mud plaster. Mud brick
(adobe) passes heat at long time, because soil has
got uncompressed volume and mud makes from
water and soil. After evaporating, there is made
empty pit. It causes that heat and cool cannot Figure 2: function of wind-catcher in hot-dry climate
arrive in molecules of soil and mud brick or adobe.
Mud plaster is mixture of wet earth with fine or chopped coarse straw. These construction materials give
the wind tower a coarse texture. The mud plaster covering the facade of a wind tower has a light color and
there for reflects rays well.
    Wind catchers also were designed in hot-
humid climate with Different function and shapes
(fig.3) and different orientation (fig.4). It is clear
that there is usually high humidity in hot and
humid regions because of their being in vicinity
of the sea. In these regions, wind towers reduce
the temperature of the weather only through the
movement of the air they facilitate, not through
increased humidity. The level of humidity in this Figure 3: function of wind-catcher in hot humid climate
region is already high and an increase in the
humidity would make living conditions
    A wind tower in a hot and dry region brings
about comfort by evaporation and air motion but
a wind tower in a hot humid region only moves
the air and conveys the wind into spaces. Wind
towers in hot humid are covered with plaster and
this type of covering resists moisture. Vapor in
the air in this region sits on the surface with Figure 4: the first figure is the win-catcher orientation in
temperature less that dew point in the hot-dry climate in centre of Iran and the second one in the
environment. If there are high penetration on hot-humid climate in south of Iran.
walls and surfaces of building, these drops
penetrate in wall for the osmosis pressure or absorption of materials. It causes demolition of surfaces. It
pushes salts of materials out of surfaces. The texture of wind towers is polished with a white color, which
also ensures that the wind towers do not absorb rays. It provides more operation in climatic function.
In the winter however, these wind towers are closed off from the rest of the house in order to top hot air
from dissipating from the interior of the house.

     It is also worth mentioning another passive
cooling technique that is often used in hot-arid
climate and occasionally in hot-humid in Iran. The
use of domes in square rooms and barrel vault roof
structures over rectangular rooms also play a role
in the passive cooling of the interior (fig.5). The
barrel vault roofing is used usually in regions
where winds blow in one direction. In this case,
heat loss by convection across the roof is
maximized. When domes are used, small air vents
are introduced in order to draw air out as a result
the wind tower effect and cooling through
evaporation. This is explained by the Figure 5: domed roof connected with wind-catchers
aerodynamics resulting from the curved shape of
the roof. Indeed, the velocity outside the roof
increases which results in a lower pressure inside
the dome. The air is then naturally drawn to the
outside of the dome.
    Wind-catcher and domed roof s are also used
in water reservoirs to keep water cool during hot
season (fig.6).

                                                      Figure 6: water reservoirs
     One other important feature of Iranian traditional houses in hot-dry and hot-humid climate is central
court yard which works as a passive cooling system and provides comfort and privacy for residential
    Courtyards are usually the heart of
the dwelling spatially, socially, and
Although, the size of the land, to some
extent, is influential, the average sizes of
the courtyards are generally determined
according to the latitude. They are
narrow enough to maintain a shaded
area during the heat of the day in
summer, but wide enough to receive
solar radiation in winter. A courtyard
can provide security, privacy, and a
comfortable place within the house. The
courtyard where it is usually planted
with trees, flowers and shrubs, not only
provides comfortable condition and
beautiful setting, but also supplies some
shade and increase the relative humidity Figure 7: central court yard and hozkhaneh (pool)
of the courtyard space. “Even without
modern, mechanical heating or cooling systems, the courtyard house provides a comfortable living
environment through seasonal usage of sections of the structure. The mass of the walls and floor of the
courtyard is cooled by outgoing long wave radiation, and therefore, the surface of the courtyard floor and
walls will remain cool by the following morning. In this way, the mass of the walls and floor of the
courtyard (and not the air deposited in the courtyard) serves as a reservoir of coolness, if it is not too large
and well shaded. For this reason one may feel cool in two ways, firstly, the courtyard air is cooled in
contact with the surrounding surfaces, and secondly, by losing heat through the surrounding surfaces by
radiation which is known as radiant cooling. The cool air that is stored in shaded areas is drawn by
convection towards the courtyards and then, high up towards the exterior of the house. This helps the
house stay cool during the day.
    One noticeable and conspicuous of urban planning in old location in cities with hot- dried and hot-
humid climates is the roofed lane and porches passage. It is called sabat (fig.8). A sabat is designed in
order to keep safe human living in desert from direct radiation of sunlight in shade for some moments and
to keep the air which flows through into the courtyards cold (fig.9). In fact, Iranian architects, in some
instances, built houses up to somewhere lying on the lane and began to build one or more protruded
rooms with same eaves above the passage all commuting was made
under these rooms called sabats. A sabat can modulate a transient
temperature. It is such a way that any pedestrian on his way to his
destination is positioned in shade in a suitable succession.

Figure 9: wind from sabat going through into the courtyards                    Figure 8: Sabat
(b)     Cold mountainous climate:

     In traditional Iranian architecture in cold regions form and way of building locating were designed for
the maximum use of the sun in cold climate (fig.10). Buildings are designed in the way to decrease the
surface which exposed to outdoor weather. In these areas the roofs are flat, and horizontal surfaces and
flat roofs absorb the most of direct sun light. Another reason for choosing for the flat roof in these areas is
to keep the snow on the roof as the heat isolator. Location and size of windows were according to the
wind and sunshine. Doors, windows and openers were located in a place with the least air pressure.

 In the areas where the wind is blowing
from a predictable direction, the strength
of the building structure against the wind
was designed less due to the way of
allocating the building on the earth.
    In cold mountainous areas, windows
facing to the south are bigger than dry and
hot area to make the best use of sun energy
and north windows are small. Since dark
colors absorb radiation more than light
colors, therefore materials of the building
façade are mainly dark in this area.
    Spaces such as rooms and main hall are
considerably smaller and ceiling is with
minimum height to decrease the inner
                                               Figure 10: stepped houses
    In some region traditional architecture were appeared by carving the mountains or big stone rock to
protect people from the cold weather (fig.11)

Figure 11.1: interior of a house

                                                                      Figure 11.2
    Materials which have been used in cold climate are all with high heat capacitance to prevent heat
loosing from inside, in this aria local materials such as stone, mud, mortar adobe and etc were commonly
(c) Mild-humid climate:

    Due to high sun energy in this area, the most attempts are made to locate the buildings in the shadows.
In this area, wide and roofed verandas are used to prevent rain and provide a shadow on room walls, too.
    Because of the high rainfall in these areas, the roofs are made with high slope. The slope level with
west-east direction gets lighter in summer in comparison with winter. Surfaces with the slope toward
south get more sun radiation in winter. In autumn and spring, the south slope surfaces get 20% or more
than the east and west slope surfaces. Surfaces with the slope towards north receive the less sun radiation
during the year.
    The way of blowing of the wind in an area is an important parameter for determining the building’s
direction. In north humid areas of Caspian Sea beaches, sea and earth breezes are blowing. In summer
when the Pressure in northern beaches of
Iran is more than the pressure in central
plateau, the air moves from the area with
high pressure .Natural ventilation, with
no except, is used in all the buildings of
this area. In general, all the buildings
have expanded and open plans and all of
them have long and narrow geometric
plans. For the main use of the wind
blowing to create natural ventilation,
rooms are located in the buildings due to
the blowing of the wind. In the areas with
high blow of the wind, all parts of the
building towards the wind are completely
closed and in some cases roof continues
until ground (fig.12). Because of using
the best of wind blowing and due to great
water sources and availability of water,
                                              Figure 12: a type of traditional hose in mild-humid climate which
the buildings        are located non-
                                              roof continues until ground
concentrated and with big distances.
    Because of humidity in this aria some
of traditional houses were built in the way to prevent the moisture to inter the house by using the pieces of
wood between the ground and the bearing walls. It causes the air ventilation under the structure. In
addition this place was used as storage to keep the stuff away from the sun radiation (fig.13). Furthermore
those pieces of woods were intentionally installed horizontally in different layers in order to have a
performance against earthquakes as well. (fig.14)
    The local materials such as timber, wooden column, Gali (plant which grows in the lagoon) for
covering roof to protect of rain penetration, mortar adobe and etc were commonly used.

                                                                     Figure 14
 Figure 13
2.2   The General Characters of Urban and Residential Design

         The general characters of urban and residential design which should be considered in
Architecture to provide suitable impact, is to concentrate on the facts which is existed in the nature and
specific climatic conditions of the region. To create the architecture, containing these facts it is required to
provide following factors to each climate conditions.

(a) Climatic design in hot & dry climate

         The flexibility of urban texture and the compatibility of living with natural conditions and using
from these harsh conditions of climate are considerable so much in this region. The most important
factors in urban and rural texture are as follows:
1-Using of natural cooling system like wind catcher, central court yard and etc
2- Very compact rural & urban texture
3- Surrounded urban spaces
4- Narrow and disordered lanes and sometimes covered with arches to provide shade
5- Connected buildings
6- Arrangement of buildings according sun and wind

(b)     Climatic design in hot & humid region in Iran

        The best way to fight against the bad climatic condition in hot-humid regions is creating shadow
and using wind. By using shadow people can walk easier and cold air providing by shadow flowing throw
the courtyards inside of building. Therefore creating shadow and using air ventilation are two factors in
urban texture and shape of building to create comfort for people.
1-design buildings according to the orientation and sun direct
2-using of architectural element and local materials according to climate condition
3- Semi-compact urban texture
4- Semi-surrounded urban spaces
5- Making shade inside and outside buildings

(c)     Climatic design in cold region:

        Because of very cold weather in most of the year, in these region buildings are connected and
have a compact texture to have less surface in touch with cold weather in outside.
Urban spaces are surrounded and small as much as possible to prevent the infiltration of cold wind in
these spaces. In addition the radiation of heating from external walls of buildings can partly reduce the
coolness of urban spaces.
        In order to keep the internal weather condition fixed in cold areas, the resistance of materials
against heat must increase. Additionally the west walls and also internal part of the building must be
constructed with some heavy materials. In the areas with severe coldness, heavy walls are necessary to
balance the heat. It is also necessary to use heat insulator to prevent heat transmission. Generally speaking
two main factors are considered while determining building materials: one is the critical outside
conditions and the other is the best temperature. First the most critical weather condition would be
recognized and then the best temperature would be determined. At the last stage the most appropriate
building materials will be chosen accordingly.
        Since getting the most sunlight is necessary in cold mountainous climate, therefore buildings
must locate toward a direction so that they can receive the highest sun radiation. Thus the main facade of
building must be placed toward the south in order to create the best heat condition inside the building. So
the northern façade of buildings decreases to the minimum surface.
The most important factors in urban and rural texture are as follows:
1- Urban and rural spaces are surrounded and small
2- Compact urban and rural texture and connected buildings
3- The orientation toward sunshine and the topography are the important factors in location and image of
4- Narrow streets

(d)     Climatic design in mild and humid climate:

         In that regions that are near the sea, high dampness is a major difficulty. Wet air is heavier than
dry air and locates in the below of dry air. So if the urban spaces are surrounded and there is not any
natural ventilation in there, this wet air will be gathered in these spaces and breathing and activity will be
so difficult. So ventilation should be used as much as possible to avoid gathering moisture in urban
         Therefore in these areas buildings constructed separately, with vast and open yards and spaces,
the fences usually are short to use air ventilation.
         The general characters that should be involved to design in this aria are:
1- Open and expanded rural and urban texture and wide streets
2- Yards with short walls
3-providing influential ventilation
4-Protecting walls and windows against sunlight and rain penetration
5-Preventing inside weather from warming in day and decreasing the warmth to the minimum amount at
         The effects of sun radiation in east and west require the buildings to have a tense format and
cubed rectangle shape and locate at the east-west axis. This method is quite useful in making a stream
inside the house and lessening humidity. If the building is located in shadow, the plan could be open and


         Climatic design means the adaptation of building with the climate of the location of building or in
the other word the compatibility of the layout of building with the climate of that region. Climate includes
the temperature of summer and winter and the volume and kind of downfall and the kind of the wind and
the volume of moisture and so on in a region.
         It can be seen clearly in nature and in the creation of animals and plants. The color and the form
of animals and plants are adaptable with the characters of each region and they have been created in a
manner that could be adaptable with the situation of that place and so they can be survived in a harsh
situation. In the architecture of the past there was the same compatibility with climate as well and actually
each region has the climatic design according the climate.
         Unfortunately after improving the technology and new inventions in mechanical utilities,
designers are depending on the systems of heating and cooling increasingly and they tries to create
comfort situation for residence of building only in this way. Because of lacking attention to the climatic
design and depending merely on artificial cooling and heating systems, the buildings are very hot in
summer and are so cold in winter and in result they are quietly uncomfortable. Then we try to create
comfort situation in buildings only with modern technology and high costs and high air and nose
pollution. If these plants corrupt, Living in these buildings will be very difficult. Besides, using fossil fuel
in a large volume will cause air pollution and removing the natural and favorite conditions of living. So it
will be better that we try again in using the climatic factors and creating junction between human and
nature. We should use modern technology when climatic design couldn't response to the needs of comfort
         It is clear that returning to the traditional construction systems is impossible and resent generation
cannot live like past generation but with reviewing and surveying of traditional experience can be found
some rules which lead us to the optimum and efficient using of climate.
         The result of this research shows that traditional architecture can give ideas to enrich modern
architecture. In traditional architecture of Iran, climate, local materials and renewable energy resources
have been used. Wind tower shows the harmony of human built environment with nature. Traditional
building techniques were normally well adapted to the climate.
         However, the modern way of life and imported western technologies have often replaced the
established traditions in the design of the buildings. This paper shows different aspect of architectural
concept adopted by people in different situations.


         Iranian vernacular version of architecture and urban planning is a representation of logical
planning version for providing all living comforts there. Use of semi- consolidate urban texture in urban
planning, planning narrowly binding or spiral- shaped lanes with high walls to provide shade in hot
seasons and in houses with central court yard, the existing typical features such as thick walls in the
central court yard, broad verandas, wind catchers to remove humidity and provide cooling in internal
spaces, planning upper windows to increase a passing ventilation and use of locally- made materials such
coral slates and stones, sedimentary rocks, bake bricks, mud plastering, wood, lumber, reed, adobe and
etc… indicates how the architects who planned such buildings good understood the environmental
conditions. Seasonal use of spaces, focusing on how to plan the central court yard and appropriate use of
roofs, though appears so simple, are efficient solutions to planning buildings. Furthermore, Iranian
traditional buildings, architectural or structural aspects, have all taken shape based on natural sources of
energies. These building have been designed in such a fashion to take in maximum sunlight in winter and
maximum shade in summer, for better natural ventilation and good comfort. The idea to provide the
architectural patterns such as central courtyard within these buildings has been formed based on climate
factors. It is, therefore, necessary to study traditional and conventional version of architecture in order to
conduct any climatic planning and create sustainable architecture. In conclusion let us to say that the
Iranian traditional architecture especially in a hot climate is considered a sustainable version of it and can
be used as a good model for designing in Contemporary architecture.


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