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Summer proof houses: Knight Frank

Knight Frank India

The following is the report by Deben Moza, Joint CEO & ED, Project Management Services, Knight Frank Property Services Pvt. Ltd.

Man invented air conditioners to get away from the harsh weather. Unfortunately, buildings don’t have that opportunity to keep away from extensive and unpredictable weather conditions.

India lies in a tropical zone which is majorly a combination of tropical and moderate climate, severe on the buildings as compared to other climates. Heat moving through the building can drastically shorten the lifespan of building.

In summer weather, thermal comfort in day depends mainly on reduction of intense radiation from sun, ground & surrounding buildings. Direct or indirect application of various materials on external and internal building façade may also help in minimizing the weathering effects on the buildings.

Today with evolving technology, construction materials have also evolved to climate responsive and environmental friendly ornaments of the building. Apart from convectional material like concrete and clay bricks, new age materials like Fly-ash Bricks, Autoclaved Calcium Silicate Bricks, Concrete Masonry Units, Foamed or Aerated CC Blocks, Husk boards and Glass have gathered popularity. Some of which are added to the list of these climate responsive materials. These materials help in the following way for achieving a comfortable environment for buildings and human life:


Ecological Compatibility: Many of these materials are produced from by product or waste which make them environmental-friendly, both in the production process and product application.

Climate Responsive: Materials like Aerated CC block are heat insulation proof materials and prevent loss of heat in winter and build-up of very high temperatures in summer, and controls air humidity in a room by absorbing and releasing moisture as per environmental conditions. Thus, they help in creating a favorable microclimate.

Phase Change Materials are also available in the market as an active ingredient of a range of semi-finished materials: plaster, cement, plasterboard and multifunctional wall and roof modules. They enable walls and ceilings to absorb and store excessive heat during the day, in order to dissipate that excessive heat during the night when air temperatures have gone down.

Alongside, many materials are used without considering their property with respect to climate conditions. One such example is Glass which has become a popular choice as it provides transparency and rigidity with its crystalline structure. But the biggest disadvantages of glass with respect to tropical and moderate climate is transmitting radiant heat, making it vulnerable to heat gain from outside sources like sun or air conditioner. Glass is also susceptible to indirect heat gain from atmosphere. Usage of glass should be minimized in tropical & moderate regions as it is high energy consuming material.

Steady interior temperature is harder to maintain unless proper measures are invoked. But with the improved technology less energy consuming glasses are available like Double and triple layered Glass, Solar-Control Glass, Tinted Glass, Coated Glass and most commonly used Soda-Lime-Silica (soft).


These materials help in minimizing heating effect in the interior spaces of the building but are not cost effective solutions and hence not on priority list for residential spaces. Judicious use of glass along west and south facades, keeping in mind sun and wind directions, is very essential.

For any building going through harsh weather conditions, insulation of walls, windows, Sun shading devices have become very important ingredients of the building. In accordance to reduce our energy consumption from the beginning one can construct in a better way so that Passive Strategies can over shadow Active Strategies.

To prevent wear and tear of the buildings and to achieve a higher degree of efficiency for upcoming new houses in tropical and moderate climates, certain parameters can be followed that will build better and sustainable homes:

• Planning –An enclosed compactly planned and essentially inward looking building is the most suitable. Design strategies incorporating courtyard planning will help in creating micro-climate. Orientation of building with respect to sun & window’s opening size and position should also be considered.

• Internal distribution – of spaces to be carried out such that buffer spaces like store rooms, staircase, toilet etc. are located on the eastern and western facades.


• Maximum utilisation – of natural ways like Earth Berming, Solar chimney/ wind tower and usage of verandahs to name a few to reduce latent heat gain. Minimising use of glasses and other high energy materials should be considered, wherever their usage is essential.

• Form– Forms can be made climate responsive such that there is minimum heat gain, reduced effect of condensation, maximum ventilation etc. example having tilted 8 degrees roof is better than flat roofs.

• Dense vegetation cover to moderate micro-climate
• Terrace gardens/Green roofs
• Light colored external surface
• Multi-layer envelops to reduce latent heat gain such as use of insulation materials in building external façade. One can also consider covering materials on external facades like clay pots (mutkas) on roofs. This is has been in practice traditionally to cut down latent heat absorption from roofs.

• Usage of External Shading Devices should be highly promoted.

In case of existing houses and flats in tropical and moderate climates, certain parameters that can be followed during summer are:


• STAKE EFFECT: Using ventilators i.e. both the supply of fresh air and convective cooling, involves the movement of air at a relatively slow rate. This can be easily incorporated by inserting miniature power vents to attic or even a thermostatically-controlled window fan to move hot air out.

• Creating MICRO-CLIMATE: Covering external areas like balconies, roofs etc. with vegetation as they act like safe guards so that air crossing them can be cooled before it enters the building. This is one way of creating passive micro-climate.

• For insulation materials to cover openings or external walls to reduce the heat gain inside the house, one can use day-to-day materials however, they may not be durable .For example thermocol which can only be used on walls or in opening that are not exposed to rain or can be used for interiors.

• Covering flat balconies or house external façade with green garden netting.
• Using double layering of curtains, combination of light and dark colour so that blockage of light as per weather can be adjusted.

• Smart usage of active strategies like enclosing areas (where A.C. isinstalled) for certain duration. This reduces further usage of A.C. For example after used at night, those rooms can be kept closed during the day to retain the coolness.