It is a document that specifies the energy performance requirements for all commercial buildings that are to be constructed in India. Buildings with electrical connected load of 500 kW or more and it is also applicable to all buildings with a conditioned floor area of 1,000 m2 (10,000 ft2) or greater are also covered by the ECBC. It was launched on 28 June 2007 by India’s Bureau of Energy Efficiency.

It was mandated by the Energy Conservation Act from 2001, by the Indian Government in September 2001.

It provides design norms to the following:

• Electrical System
• Water heating and pumping system
• Lighting and envelope system of a building.
• HVAC system that includes energy performance of chillers and distribution systems.
• Ventilating systems

This code does not apply to the following 

• Buildings that do not use either electricity or fossil fuel,
• Equipment and portions of building systems that use energy primarily for manufacturing processes
• Multi-family buildings of three or fewer stories above grade, and single-family buildings.

The Building which follow ECBC code are rated on 1- 5 star scale, with 5-Star labeled buildings being the most energy efficient. It is normally targeted three climatic zones for air-conditioned and non-air-conditioned office buildings:

         1. Warm and Humid
         2. Hot and Dry
         3. Composite

Energy Performance Index (EPI) in kWh / sq m/ year will be considered for rating the building. Bandwidths for Energy Performance Index for different climatic zones have been developed based on percentage air-conditioned space. For example a building in a composite climatic zone like New Delhi and having air conditioned area greater than 50% of their built up area, the bandwidths of EPI range between 190-90 kWh/sq m/year. Thus a building would get a 5-Star rating if its EPI falls below 90kWh/sq m/year and 1 Star if it is between 165-190 90kWh/sq m/year.

Similarly the same building in a warm and humid climatic zone like Chennai, the bandwidths of EPI range between 200-100 kWh/sq m/year and therefore it would get a 5-Star rating if its EPI is below 100 kWh/sq m/year and 1 Star if it is between 200-175 kWh/sq m/year.

Buildings having air conditioned area less than 50% of their built up area,in a in a composite climatic zone the bandwidths of EPI range between 80-40 kWh/sq m/year. Similarly the same building in a warm and humid climatic zone like Chennai, the bandwidths of EPI range between 85-45 kWh/sq m/year.
The Star rating Programme would provide public recognition to energy efficient buildings, and create a “demand side” pull for such buildings. Those buildings having a connected load of 500 kW and above would be considered for BEE star rating scheme.

EPI shall be kWh/sq.m/year in terms of purchased & generated electricity divided by built up area in sq.m. However the total electricity would not include electricity generated from on-site renewable sources such as solar photovoltaic etc.

The Bureau over the past 2 years, launched the Energy Conservation Building Code(ECBC) with the goal of specifying standards for new, large, efficient commercial buildings, as well as initiated a nationwide programme to upgrade the energy efficiency of existing government buildings through retrofitting, carried out by Energy Service Companies (ESCOs) in a performance Contracting mode.