Green building ratings: GRIHA and IGBC

In short

GRIHA and IGBC are India's two principal voluntary green-building rating systems: a project earns points against criteria for site, energy, water, materials, waste, indoor environment and innovation, and a third party awards a rating (GRIHA stars, IGBC Certified/Silver/Gold/Platinum). GRIHA was developed by TERI and is run by the GRIHA Council (ADaRSH); it is the system endorsed by the Ministry of New and Renewable Energy and used for most central-government and CPWD projects. IGBC is a council of the Confederation of Indian Industry (CII), based at the CII-Sohrabji Godrej Green Business Centre, Hyderabad, and has the larger private-sector and corporate footprint. Both sit on top of mandatory law — ECBC 2017 / Eco Niwas Samhita for energy and the local building bye-laws — and both are linked to incentives such as extra FAR and property-tax rebates in several states. Examined in architecture and civil syllabi under sustainability/building services, and asked in interviews at HOK, Edifice, CBRE, JLL, L&T, Godrej Properties, Tata Projects, Environmental Design Solutions and every green-building consultancy.

Explained

What a rating system is and why India has its own

• A rating system is a structured checklist: criteria → points (credits) → total score → a rating band, verified by documents and site audit by a third party, not self-declared.
• It converts a vague goal ("sustainable building") into measurable, auditable performance: kWh/m²/year, litres per capita per day, percent recycled content, percent construction waste diverted.
• Indian systems exist because imported benchmarks mismatch Indian climate (five climate zones), construction practice (masonry, in-situ RCC, manual labour), tariffs and water scarcity. LEED was first used in India as LEED India under licence from USGBC; IGBC later issued its own India-specific rating systems, and LEED projects in India are now certified directly by USGBC/GBCI.
• Three complementary layers: (1) mandatory — building bye-laws, NBC 2016 Part 11 "Approach to Sustainability", ECBC/ENS as adopted by the state; (2) voluntary rating — GRIHA, IGBC, LEED, EDGE (IFC); (3) performance labels — BEE Star Rating for buildings (1–5 stars from measured EPI) and net-zero certifications.

GRIHA — structure and working

• Full form: Green Rating for Integrated Habitat Assessment. Developed by TERI, administered by GRIHA Council / ADaRSH (Association for Development and Research of Sustainable Habitats), a society formed by TERI with MNRE support; adopted as the national rating system by MNRE.
• Scoring: 100 points, distributed across criteria grouped broadly as — sustainable site planning; construction management; energy optimisation and renewables; occupant comfort and well-being (thermal, visual, acoustic, IAQ); water management; solid-waste management; sustainable building materials; life-cycle costing; socio-economic strategies (labour welfare, universal accessibility); performance monitoring and validation; plus bonus/innovation points. The number of criteria and the split of points changed between v2015 and v2019 — quote the version you are using.
• Star bands (classic GRIHA scale): 50–60 → 1 star, 61–70 → 2 stars, 71–80 → 3 stars, 81–90 → 4 stars, 91–100 → 5 stars. Minimum thresholds have been revised across versions; verify against the current GRIHA v2019 manual.
• Mandatory (appraisal-critical) criteria exist — e.g. topsoil preservation, construction-waste and labour-safety provisions, segregated waste, minimum energy and water performance. Failing a mandatory criterion bars certification whatever the total score.
• Process: registration → design-stage documentation → preliminary appraisal (provisional rating) → construction → final documentation and site visit → final rating after completion/occupancy, so GRIHA tests delivered performance, not only intent. The award is valid for a fixed term (five years in current practice) after which re-evaluation is required.
• Variants: GRIHA v2019 (new buildings), SVAGRIHA (Simple Versatile Affordable GRIHA — small projects, typically under about 2,500 m², fewer criteria, online tool), GRIHA for Existing Buildings, GRIHA for Affordable Housing, GRIHA LD (Large Developments/habitats), GRIHA for Cities, and sector versions (e.g. railway stations). Pre-certification is available at design stage.
• Professional credential: GRIHA CP (Certified Professional) via training and examination; GRIHA Trainer and Evaluator tracks above it.

IGBC — structure and working

• IGBC = Indian Green Building Council, formed in 2001 as part of CII. Its own building, the CII-Sohrabji Godrej Green Business Centre in Hyderabad, was India's first LEED Platinum building (rated 2003, the first outside the USA).
• Credit categories in IGBC Green New Buildings (seven): (1) Sustainable Architecture and Design; (2) Site Selection and Planning; (3) Water Conservation; (4) Energy Efficiency; (5) Building Materials and Resources; (6) Indoor Environmental Quality; (7) Innovation and Development. Each has mandatory requirements plus optional credits.
• Certification levels: Certified, Silver, Gold, Platinum, awarded on a 100-point scale. Typical bands are Certified 40–49, Silver 50–59, Gold 60–74, Platinum 75–100 — but the bands and totals differ between IGBC rating systems and versions, and some separate owner-occupied from tenant-occupied buildings; always read the version-specific abstract.
• Process: registration → design submittal → pre-certification (optional, widely used for marketing under RERA-era sales) → construction → final submittal → review (preliminary + final, with clarifications) → certification, with site verification. Operation-and-maintenance ratings are time-limited (about three years) and need recertification.
• Rating systems (indicative, ~30): Green New Buildings, Green Homes, Green Existing Buildings O&M, Green Factory Building, Green Townships, Green Residential Societies, Green Schools, Green Campus, Green Healthcare, Green Data Centres, Green Interiors, Green SEZ, Green Logistics Parks, Green Mass Rapid Transit System, Green Railway Stations, Green Cities and Villages, Green Affordable Housing, plus Net Zero Energy / Water / Waste / Carbon certification programmes.
• Professional credential: IGBC AP (Accredited Professional) examination — a standard asking point in green-consultancy interviews; a project earns a credit for having an AP on the team.

The mandatory codes the ratings sit on

• Energy Conservation Act, 2001, as amended in 2022, empowers BEE to notify an energy code; the amendment extends its scope towards an Energy Conservation and Sustainable Building Code (ECSBC) covering residential buildings and embodied aspects — adoption is state-wise, so check your state's notification.
• ECBC 2017 (commercial buildings above the notified connected load/contract demand) sets envelope, lighting, HVAC, service hot water and electrical requirements, with three performance tiers: ECBC-compliant, ECBC+ and SuperECBC, each defined by an EPI ratio limit per climate zone. Compliance routes: prescriptive, whole-building performance (simulation), and trade-off for the envelope.
• Eco Niwas Samhita — the residential code: ENS 2018 (Part I, envelope) limits the RETV (Residential Envelope Transmittance Value) to 15 W/m² for composite, hot-dry, warm-humid and temperate zones, caps roof U-value at 1.2 W/m²·K, and sets minimum openable area and visible light transmittance; ENS 2021 (Part II) covers electro-mechanical systems and renewables.
• NBC 2016 Part 11 gives the sustainability framework; MoHUA Model Building Bye-laws 2016 carry green provisions (rainwater harvesting, solar water heating, waste segregation) that states and ULBs adopt. Environmental clearance rules for large built-up projects have changed repeatedly and been litigated — verify the notification in force rather than quoting an old threshold.
• A rating is voluntary; code compliance is statutory. A GRIHA 5-star or IGBC Platinum building that fails ECBC is still illegal.

Incentives, comparison and limitations

• Incentives in Indian practice: additional FAR/FSI (commonly 1–5%, e.g. schemes in Maharashtra, UP/Noida, Telangana, West Bengal, Rajasthan), property-tax rebates, fast-track plan approval, and preference in CPWD/PSU tenders; MNRE and several ministries require GRIHA ratings (commonly 3-star and above) for government buildings. Scheme details vary by ULB and change often — confirm locally.
• GRIHA vs IGBC in one line: GRIHA is government-endorsed, absolute-benchmark-oriented, rates the completed and occupied building and emphasises construction-stage impacts, labour welfare and life-cycle cost; IGBC is industry-driven, has many more sector-specific systems, strong pre-certification and faster market uptake.
• Advantages: measurable targets; 20–40% typical energy savings and 25–50% water savings against conventional practice; better IAQ and daylight; documentation discipline; marketing and financing value (green bonds, ESG reporting, BRSR disclosures); resale and rental premium in Grade-A offices.
• Limitations: points can be "gamed" — easy credits bought while the hard energy credits are skipped; design-stage certification need not match operating performance (the performance gap); embodied carbon is weakly addressed in older versions; certification and consultancy cost (registration plus fees plus simulation) is significant for small projects; no rating is a substitute for climate-responsive passive design.

Key points

• GRIHA - Green Rating for Integrated Habitat Assessment; TERI-developed, run by GRIHA Council (ADaRSH), endorsed by MNRE as the national system.
• IGBC - Indian Green Building Council, part of CII, Hyderabad; issues ~30 India-specific rating systems plus net-zero programmes.
• GRIHA scale - 100 points; classic bands 50–60 (1 star) rising to 91–100 (5 stars); mandatory criteria must be met regardless of score.
• IGBC levels - Certified, Silver, Gold, Platinum on a 100-point scale; bands differ by rating system and version.
• IGBC's seven categories - sustainable architecture and design, site, water, energy, materials, indoor environment, innovation.
• GRIHA's emphasis - construction management, life-cycle cost, socio-economic strategies and post-occupancy validation.
• Pre-certification - design-stage recognition (both systems); final rating needs built-stage verification.
• EPI - Energy Performance Index in kWh/m²/year, the single most-used Indian energy metric for buildings.
• ECBC 2017 - mandatory commercial energy code with ECBC / ECBC+ / SuperECBC tiers; prescriptive, trade-off and whole-building-performance routes.
• Eco Niwas Samhita - residential code; RETV ≤ 15 W/m² for four climate zones, roof U ≤ 1.2 W/m²·K.
• BEE Star Rating - operational label for buildings based on measured EPI; different from a design rating.
• LEED India - LEED was licensed to IGBC earlier; LEED in India is now certified by USGBC/GBCI, while IGBC runs its own systems.
• EDGE - IFC's rating; a 20% reduction in energy, water and embodied energy in materials is its entry benchmark.
• Credentials - GRIHA CP and IGBC AP; an accredited professional on the team earns a credit.
• Incentives - extra FAR, tax rebates, faster approvals; GRIHA commonly mandated for central-government buildings.
• Voluntary vs statutory - a rating never replaces bye-laws, NBC 2016 Part 11 or ECBC/ENS compliance.
• Performance gap - certified design performance often exceeds actual operating performance; measurement and verification closes it.
• Indian exemplars - Indira Paryavaran Bhawan, Delhi (GRIHA 5-star, net-zero energy); CII-Godrej GBC, Hyderabad; Suzlon One Earth, Pune.

Formulas and examples

Example 1 — GRIHA score to star rating (illustrative criterion-wise score).

• Core total = 10+24+14+6+10+8+4+5+3 = 84 → band 81–90 → 4 stars.
• With 2 bonus points, 86 — still inside 81–90, so still 4 stars: the project needs 91 for 5 stars, i.e. 5 more points, cheapest from renewables or water. Note bonus points cannot push the total above 100.
• If one mandatory criterion (say construction-waste management) were unmet, the project would get no rating at all despite 84 points.

Example 2 — EPI, ECBC saving and IGBC energy credits. An office of 10,000 m² consumes 1,100,000 kWh/year; the ECBC base case simulates 1,600,000 kWh/year.

• EPI(proposed) = 1,100,000 / 10,000 = 110 kWh/m²/year; EPI(base) = 160 kWh/m²/year.
• EPI ratio = 110/160 = 0.6875.
• Saving = (1 − 0.6875) × 100 = 31.25% — comfortably past ECBC-compliant and in the range that earns a high block of energy points in both GRIHA and IGBC (exact points depend on version and climate zone).
• Add 300 kW of rooftop PV at a 16% capacity factor: 300 × 8,760 × 0.16 = 420,480 kWh/year, i.e. 38% of the building's consumption — net EPI = (1,100,000 − 420,480)/10,000 = 68 kWh/m²/year.

Example 3 — water conservation credit. 500 occupants; baseline fixture demand 45 LPCD, efficient fixtures (dual-flush 3/6 L, 4 L/min aerated taps, waterless/low-flush urinals) give 29 LPCD.

• Baseline = 500 × 45 = 22,500 L/day; design = 500 × 29 = 14,500 L/day.
• Saving = 8,000 L/day → % reduction = 8,000/22,500 × 100 = 35.6%, which crosses the 30–35% thresholds used for water-efficiency credits.
• Annual saving at 300 working days = 8,000 × 300 = 2,400,000 L = 2,400 m³/year.

Example 4 — rainwater harvesting and roof SRI. Roof catchment 1,200 m², annual rainfall 900 mm, C = 0.85, filter efficiency 0.90.

• V = 1,200 × 0.90 × 0.85 × 0.90 = 826.2 m³/year ≈ 8.26 lakh litres — i.e. 34% of the 2,400 m³ annual fixture saving computed above, so it is a useful but partial supply, best used for landscape and flushing.
• Heat-island credit: roof 2,000 m², of which 200 m² is under equipment/services and excluded; high-SRI (SRI ≥ 78) finish on 1,400 m². Compliance = 1,400 / (2,000 − 200) × 100 = 77.8%, which meets a typical "≥ 75% of roof area" requirement.

Example 5 — business case and payback. Project cost ₹30,000/m² × 10,000 m² = ₹30 crore; incremental green cost 4% = ₹1.2 crore.

• Energy saving = (160 − 110) × 10,000 = 500,000 kWh/year at ₹9/kWh = ₹45,00,000/year.
• Water saving = 2,400 m³ at ₹60/m³ = ₹1,44,000/year. Total ≈ ₹46.44 lakh/year.
• Simple payback = 1,20,00,000 / 46,44,000 = 2.58 years; a 3% FAR incentive on 10,000 m² = 300 m² extra saleable area, worth several crore in a metro, which usually dominates the economics.

Where it is used

• Green-building consultancies and ESG advisory (Environmental Design Solutions, cKinetics, consultancy arms of CBRE, JLL, Colliers, Knight Frank): registration, simulation, documentation, submittal and certification management; IGBC AP / GRIHA CP is often an eligibility requirement.
• Developers and corporate real estate: Godrej Properties, Embassy, DLF, Mahindra Lifespaces, Infosys and Wipro campuses use pre-certification in leasing and in BRSR/ESG disclosures; Grade-A office leasing routinely specifies IGBC Gold/Platinum or LEED.
• Government and institutional projects: CPWD, state PWDs, Smart Cities, AIIMS/IIT/IIM campuses and Indian Railways station redevelopments with GRIHA or IGBC targets; Indira Paryavaran Bhawan (Delhi) and Suzlon One Earth (Pune) are standard case studies.
• MEP, HVAC and energy-simulation roles: EPI and ECBC/ENS compliance modelling in EnergyPlus/eQUEST/DesignBuilder, commissioning and measurement-and-verification for the energy credits.
• Manufacturers and products: fly-ash and AAC blocks, low-VOC paints, high-SRI roof coatings, low-flow sanitaryware, BEE-labelled equipment and GreenPro-certified products marketed by their contribution to specific credits.
• Urban local bodies and plan sanction: FAR and tax incentive schemes, rainwater harvesting and solar mandates in bye-laws, verification of green claims at occupancy-certificate stage.

Interview questions

• Q: Who owns GRIHA and who owns IGBC? A: GRIHA was developed by TERI and is administered by the GRIHA Council (ADaRSH) with MNRE endorsement; IGBC is part of the Confederation of Indian Industry, headquartered at the CII-Godrej Green Business Centre, Hyderabad.
• Q: What is the single biggest difference in when the two award a rating? A: GRIHA's final rating comes after construction and occupancy, validating delivered performance, whereas IGBC's pre-certification lets a project claim a design-stage rating well before completion.
• Q: Does an IGBC Platinum rating mean the building complies with ECBC? A: Not automatically — ratings are voluntary and code compliance is statutory; a project must satisfy ECBC 2017 or Eco Niwas Samhita as adopted by the state regardless of its rating.
• Q: What is EPI and a typical target? A: Energy Performance Index, annual energy use per square metre (kWh/m²/year); Indian air-conditioned offices conventionally run roughly 180–250, while efficient ECBC-plus designs reach about 80–120 and net-zero designs go lower with on-site renewables.
• Q: What does RETV mean and what is its limit? A: Residential Envelope Transmittance Value under Eco Niwas Samhita 2018, a single envelope heat-gain indicator capped at 15 W/m² for composite, hot-dry, warm-humid and temperate climates, with roof U-value limited to 1.2 W/m²·K.
• Q: A project scores 84 points in GRIHA but misses one mandatory criterion. What happens? A: It is not certified; mandatory criteria are pass/fail prerequisites and no score compensates for failing one.
• Q: How do green ratings earn money for a developer in India? A: Through additional FAR/FSI and tax rebates offered by several states and ULBs, lower operating cost, faster leasing at a rent premium, and ESG/green-finance eligibility — the FAR bonus usually outweighs the energy saving.
• Q: What is SRI and where is it used in a rating? A: Solar Reflectance Index, computed from solar reflectance and thermal emittance (ASTM E1980) on a scale where standard black is 0 and standard white 100; high-SRI finishes on a specified fraction of roof and paved area earn heat-island-reduction credits.
• Q: Which Indian rating is normally specified for a central-government office building? A: GRIHA, commonly 3-star and above, following MNRE's endorsement and CPWD practice.
• Q: What is the "performance gap" and how is it addressed? A: The shortfall between simulated/certified performance and measured operation, caused by occupancy, controls and poor commissioning; it is addressed by commissioning, sub-metering, measurement and verification, O&M ratings and BEE's measured star rating.
• Q: Name a rating aimed at affordable or small projects. A: SVAGRIHA for small projects (broadly under about 2,500 m²), GRIHA for Affordable Housing, IGBC Green Affordable Housing, and IFC's EDGE with its 20% energy, water and material-embodied-energy threshold.
• Q: Why can a building be certified and still be uncomfortable? A: Points can be collected from peripheral credits while passive design — orientation, shading, mass, ventilation — is weak; certification measures credits earned, not thermal comfort directly.

Common mistakes

• Quoting GRIHA or IGBC point totals and bands from an obsolete version; thresholds, criteria counts and category weights differ between versions and between IGBC rating systems — always cite the version.
• Confusing a design rating (GRIHA/IGBC/LEED) with an operational label (BEE star rating from measured EPI) or with code compliance (ECBC/ENS).
• Saying LEED India is still issued by IGBC; IGBC now runs its own rating systems and LEED projects in India are certified by USGBC/GBCI.
• Treating mandatory criteria as optional credits, or assuming bonus/innovation points can lift a score beyond 100.
• Computing EPI on total built-up area in one case and conditioned area in another, or mixing kWh/year with kWh/month — the index is meaningless without its area basis and period.
• Forgetting the runoff coefficient and first-flush/filter losses in rainwater calculations, which overstates the harvest by 20–30%.
• Claiming a fixed FAR bonus nationally; the incentive, its percentage and the rating level required are decided state- and ULB-wise and change frequently.

Related topics

Climate-responsive design · Building bye-laws and the National Building Code · Energy Conservation Building Code and building energy simulation · Water supply, rainwater harvesting and wastewater reuse in buildings · Building materials, embodied energy and life-cycle assessment · HVAC, daylighting and indoor environmental quality