IGBC v3 (Green New Buildings v3) is the Indian Green Building Council’s third-generation rating for new commercial/institutional buildings. The Energy Efficiency (EE) category is where 35-45 of the 110-point total live for typical Indian projects — making it the largest single category by point value.
This guide walks the EE credit structure, the ECBC 2017 baseline that underlies it, and the typical Indian-project mix that captures these points.
IGBC v3 EE credit structure
IGBC v3 EE has 5 main credit areas:
| Credit | Description | Max points |
|---|---|---|
| EE-Mandatory 1 | ECBC compliance | required |
| EE-1 | Energy performance (ECBC + reductions) | 35 |
| EE-2 | On-site renewable energy | 5 |
| EE-3 | Off-site renewable | 3 |
| EE-4 | Optimum energy performance | 2 |
| **TOTAL EE** | **45+** |
Plus EE-related items in other categories (CO2, MA, etc.).
Energy savings vs ECBC 2017 baseline:
| Energy savings vs ECBC 2017 | IGBC v3 EE-1 points |
|---|---|
| 5% (mandatory) | 0 (just compliance) |
| 10% | 5 |
| 15% | 10 |
| 20% | 15 |
| 25% | 20 |
| 30% | 25 |
| 35% | 30 |
| 40% | 35 |
Compare to LEED v4.1: at 30% savings LEED gives 6 points, IGBC gives 25. IGBC is more generous — 30% savings is the sweet spot for both ratings.
ECBC 2017 baseline difference from ASHRAE 90.1
ECBC 2017 differs from ASHRAE 90.1 in important ways for Indian projects:
| Aspect | ECBC 2017 | ASHRAE 90.1-2019 |
|---|---|---|
| Climate zones | 5 (CZ1-CZ5 hot, mild, etc.) | 8 (CZ1-CZ8) |
| LPD baseline | Higher (e.g. 9.0 W/m² office) | Lower (e.g. 7.5 W/m²) |
| Chiller IPLV minimum | 5.50 (water-cooled centrifugal) | 6.30+ depending on size |
| Envelope U-values | Less stringent | More stringent |
| OA requirements | NBC 2016 (higher than 90.1) | ASHRAE 62.1 |
In practice, ECBC 2017 is easier to beat than ASHRAE 90.1 — Indian designers can claim higher percentage savings under IGBC than under LEED for the same building. This is one reason IGBC v3 is simpler to certify than LEED v4.1 for Indian projects.
Typical strategies for 30% savings vs ECBC
For 5,000 m² office in Mumbai/Chennai climate:
LED + DCV (baseline minimum)
- Specify LEDs at 110 lm/W; LPD = 7.5 W/m² vs ECBC baseline 9.0 = 17% reduction in lighting energy
- Add DCV with 30% NBC lockout: ~10% reduction in OA conditioning
- Combined: ~12-15% savings = IGBC EE-1: 5-10 points
Plus ERV + free cooling
- ERV on outdoor air (75% sensible, 70% latent): 15-20% reduction in OA conditioning
- Free cooling (waterside economiser): 10-15% reduction in chiller hours
- Combined: 25-30% savings = IGBC EE-1: 20-25 points
Plus DOAS + chilled beam
- DOAS replaces VAV; chilled water at 12 °C instead of 7 °C: chiller efficiency +25%, no reheat
- Combined: 35-40% savings = IGBC EE-1: 30-35 points
Plus on-site PV
- 200 kW PV array provides ~330,000 kWh/year ≈ 6.5% of building energy
- IGBC EE-2: 3-5 points additional
Plus VFDs throughout
- Pump + fan kW reduction 15-20%
- Net: 38-43% savings = ~33 IGBC points
For a typical 5,000 m² Indian office with strong design, 35-40 IGBC EE points is realistic and economically defensible.
Worked example: 10,000 m² IT office, Bangalore
Baseline ECBC 2017 EUI for office in CZ Mild = ~120 kWh/m²/year. Site total: 1,200 MWh/year.
Proposed strategies:
- LED + daylight: -10%
- DCV: -8%
- ERV: -8%
- Free cooling (Bangalore): -15% (5,000 free-cooling hours/year)
- DOAS + chilled beam: -10%
- VFDs: -5%
- 100 kWp PV: -8% (offsets via on-site renewable)
- Net combined: ~50% savings (with diminishing returns accounted)
EUI achieved: 60 kWh/m²/year. Excellent.
IGBC points captured:
- EE-1 at 50%+ savings: 35 points (max)
- EE-2 on-site renewable: 5 points (max)
- EE-3 off-site renewable: 3 points if user buys green tariff or RECs
- EE category total: 43 of 45 available
Plus other categories (Sustainable Sites, Water Efficiency, Indoor Environment, Innovation): 60-65 additional. Total: 100-110 points = Platinum rating (typical 75+ threshold).
ECBC + ECO Niwas Samhita (residential)
For residential projects, the relevant code is ECO Niwas Samhita 2018 (ECBC’s residential sibling). It’s far less stringent than ECBC 2017 commercial; achieving IGBC v3 Residential easily requires careful envelope + LED + ceiling fan strategy.
For mixed-use (commercial podium + residential tower), the project follows ECBC 2017 for commercial and ECO Niwas Samhita for residential portions.
Five common IGBC v3 EE mistakes
1. Targeting LEED-thresholds, missing IGBC bonus. IGBC is more generous than LEED at 30% savings; reach 30% savings = 25 IGBC points + 6 LEED points.
2. Not modeling free cooling in baseline + proposed. Baseline ECBC doesn’t free-cool; proposed-case can capture all hours = full energy benefit credited.
3. No on-site PV planned. Easy 5 points (5% of 1,200 MWh/year) requires only a small PV array.
4. DCV not modeled, only specified. Energy model must show CO2-occupancy correlation; otherwise no credit captured.
5. Equipment efficiency at ECBC minimum, not ECBC + 10%. ECBC minimum gets EE-Mandatory; spec’ing 10% above captures EE-4 optimum performance + bonus EE-1 percentage.
Quick checklist
- [ ] ECBC 2017 baseline modeled per IGBC reference
- [ ] Proposed-case includes: LED, DCV, ERV, free cooling, DOAS (where applicable), VFDs
- [ ] On-site renewable PV or green tariff for EE-2/EE-3
- [ ] Chiller IPLV ≥ 7.0 (for EE-4 optimum)
- [ ] Energy savings tabulated and submitted as part of IGBC documentation
- [ ] BEE star labels referenced for major equipment
- [ ] Performance verification commissioning plan documented
References: IGBC Green New Buildings Rating System v3 (2020); ECBC 2017; ECO Niwas Samhita 2018 (residential); BEE Star Labelling Programme 2024; ASHRAE 90.1-2019 (companion).
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