Over the years, traditional wisdom has supported the idea of a water body such as pond, lake or a fountain to provide cooling effect to the surrounding environment. This effect lowers the indoor air temperature – a widely known concept of evaporative cooling.  This phenomenon is largely witnessed in systems such as desert coolers in most Indian households.

Evaporative cooling lowers the indoor air temperature thus lowers the energy cost for air-conditioning in buildings. Reduced energy load contributes towards meeting the NZEB design goals. However, evaporative cooling is mostly effective in hot and dry climate where the humidity is low.

• Pools, ponds and water features immediately outside windows or in courtyards can pre-cool air entering the house. As water evaporates it draws large amounts of heat from surrounding air.
• In public buildings, water in pools and fountains can be used as a cooling element along with cross-ventilating arrangement of openings.
• Cooling towers The cooling tower may be used to evaporate, precool ventilation air for one or more air handling units (AHU), reducing the load on the mechanical cooling system.
• Evaporative cooling is most effective in hot and dry climates.
• Vegetation for evaporation: The evapotranspiration from one tree can save 250 to 650 kWh of electricity used for air-conditioning per year. Evapotranspiration from wet grass can reduce the ground surface temperature by 6-8°C below the average surface temperature of the bare soil.
• Use of porous materials: Roof materials can cause evaporative cooling effect e.g. The siliceous shale is able to reduce the roof surface temperature by about 8.63°C, as compared to mortar concrete.