Adopting Low-cost Alternative for Energy Saving
Energy Saving Potential

This section showcases the energy conservation measures in a building with ECBC envelope case. The Energy Conservation Measures considered here are ECBC compliant wall, roof & window, with Daylight integration and optimum Window Wall Ratio (WWR). Although there is energy saving potential from individual ECBC wall and roof and window, the overall energy saving potential from the ECBC envelope as a whole strategies are mentioned here under.

  • ECBC wall
  • ECBC roof
  • ECBC window
  • Daylight integration and optimum WWR

For more information on the ECBC envelope, refer Technical Information Section.


Daylight integration

Window Wall Ratio

U-value : 0.391 W/m2°C

U-value : 2.22 W/m2°C

U-value : 0.385 W/m2°C

Daylight integration

(20- 30)%


Impact of Energy Conservation Measures-2 design Strategies:

Energy Performance Index of an ECBC envelope with daylight integration and optimum WWR in a day use and 24 hour use building with above mentioned energy conservation measures is in the following range:

Dayuse Building

24 Hour use Building

Lighting: 64.35 (kWh/m2/annum)
HVAC: 88.97(kWh/m2/annum)
EPI of the building (including lighting & HVAC
consumption only): 153.3 (kWh/m2/annum)

Lighting: (kWh/m2/annum)
HVAC: (kWh/m2/annum)
EPI of the building (including lighting & HVAC
consumption only): (kWh/m2/annum)


It is also observed in air-conditioned buildings for both day use and 24 hour-use, ECBC compliant envelope + daylight integration & optimum WWR has high energy saving potential. However, it is also observed that the cost of complying with ECBC recommendations is high and it gives the energy saving potential as low energy design strategies. So ECBC wall and roof could be trade off by shading of roof and shading of East & West walls. The below graphs shows the reduction in energy consumption in a day time and 24 hour-use buildings by adopting low energy strategies;

Fig 1: Energy saving potential due to ECBC compliant envelope (ECBC envelope + Daylight integration and optimum WWR) in a day use building

**Note: The energy saving potential of Energy Conservation Measures (ECM2), is calculated with Building Envelope against Base case (conventional building). Low energy design strategies, lighting and HVAC systems in ECM2 are same as in Base case/Conventional Building

It is noted that adopting ECBC measures, the energy saving potential in a day use building is more than that in a 24 hour use building

Life Cycle Cost Analysis:

The Life Cycle Cost Analysis (LCC) of this Strategy (ECBC Envelope and daylight integration with optimum WWR of 0.30) was carried out under this project. The payback period is 2-3 years which makes the case economically more viable in comparison to only ECBC compliant envelope without daylight integration, where payback period is higher.
The pay back period of ECBC envelope and shaded envelope is same in the above carried analysis. However, in case of shaded envelope, the pay back period can be lowered by using local construction techniques and local materials.

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