Rooftop Solar in India: How Building Codes Are Making It Standard in New Construction

Every additional AC that is turned, every EV that is purchased, increases the electricity demand in our country, a rising concern in rapidly expanding cities. To meet these needs India is beginning to embed rooftop solar into the rules that shape how buildings are designed and approved. Building codes set the minimum standards a structure must meet before it receives regulatory approval. To improve energy supply and stability these standards include energy performance parameters, solar-ready rooftops, renewable energy (RE) infrastructure, and, in some cases, mandatory solar water heating.

This blog explores the national building codes that matter for rooftop solar, what each requires, and how they are gradually shifting solar from an optional add-on to a design-stage consideration.

India’s Framework

India’s framework operates through a layered system of codes issued by a different authority, applying to a different category of building, and each requiring state-level adoption before it becomes legally enforceable. 

The five codes that matter most for rooftop solar are:

1. National Building Code (NBC) 2016
2. Model Building Bye-Laws (MBBL) 2016
3. Energy Conservation Building Code (ECBC) 2017
4. Energy Conservation and Sustainable Building Code (ECSBC) 2024 
5. Eco Niwas Samhita (ENS) 2024 — the residential counterpart to ECSBC

1. National Building Code (NBC) 2016

Issued by: Bureau of Indian Standards (BIS)
Applies to: All buildings — when adopted by states

NBC is the broadest reference standard for construction in India. 

Solar provisions:  

• Hospitals, hotels, and residential buildings with centralised hot water systems must meet their hot water demand partly through solar water heating — at least 20% for smaller buildings, rising to at least 40% for buildings with above-grade floor area of 20,000 m² or more. 
• For solar PV, the NBC recommends provisioning at least 1 kWp per 100 m² of roof area as a planning benchmark.

The NBC also identifies the Energy Conservation Building Code (ECBC) as the benchmark standard for energy performance in commercial buildings.

2. Model Building Bye-Laws (MBBL) 2016

Issued by: Town and Country Planning Organisation (TCPO), Ministry of Housing and Urban Affairs
Applies to: ULBs across India — as a template

The MBBL is a template — a model framework that state governments and municipal bodies can use when drafting their own building regulations.

Solar provisions:  

• Includes provisions for rooftop solar panel installation as a planning requirement.
• Enables local authorities to make solar installation mandatory for buildings above certain plot sizes — generally starting from 500 m².

MBBL specific thresholds — plot area, building type, minimum capacity — vary by city.

3. Energy Conservation Building Code (ECBC) 2017

Issued by: Bureau of Energy Efficiency (BEE), Ministry of Power
Applies to: New commercial buildings with connected load ≥ 100 kW or contract demand ≥ 120 kVA

The ECBC 2017 is India’s primary energy performance standard for commercial buildings. It covers the full envelope of a building — from HHVAC and lighting efficiency to the provision for on-site RE.

Solar provisions:The ECBC uses a three-tier compliance structure:

The code also mandates that at least 25% of the usable rooftop area must be designated as a shadow-free solar zone. This means the space must be free of obstructions — water tanks, mechanical equipment, signage etc— to allow future or current solar panel installation.

4. Energy Conservation and Sustainable Building Code (ECSBC) 2024

Issued by: Bureau of Energy Efficiency (BEE)
Applies to: New commercial buildings with connected load ≥ 100 kW or contract demand ≥ 120 kVA

The ECSBC 2024 is the updated successor to ECBC 2017. It retains the three-tier structure of the ECBC but raises the ambition at each level.

Solar provisions: Like ECBC, ECSBC 2024 operates across three tiers:

Beyond the tiered structure, ECSBC 2024 has:

Solar water heating for hospitals and hotels: Buildings in the hospitality and healthcare sectors, across all climatic zones, must install solar water heating equipment to cover at least 60% of the total hot water requirement.

Mandatory electrical infrastructure for solar: Even at the baseline mandatory tier, buildings must install dedicated circuit breakers, earthing provisions, conduit, and metering infrastructure to support future solar integration.  

5. Eco Niwas Samhita (ENS) 2024

Issued by: Bureau of Energy Efficiency (BEE)
Applies to: New residential buildings with connected load ≥ 100 kW, contract demand ≥ 120 kVA, or plot area ≥ 3,000 m²

The residential sector has its own separate code: the Eco Niwas Samhita (ENS)is a consolidated update that integrates envelope performance, electro-mechanical systems, and sustainability provisions — including RE.

Solar provisions: : ENS 2024 takes a “solar readiness” approach rather than a solar installation mandate:

• Rooftop areas in covered residential buildings must be designated for future solar installation, meaning designs must account for panel placement and access. Actual solar installation is not yet mandatory
• ENS 2024 also includes a points-based incremental system (ENS+ and Super ENS tiers) where additional points can be earned for renewable energy measures, improving the building’s overall sustainability score.

ENS 2024 uses connected load or contract demand as the primary trigger — meaning large apartment complexes and group housing projects are now covered based on their electrical load, regardless of plot size. States retain the flexibility to modify the plot area threshold for their jurisdiction.

Conclusion

Taken together, these codes show a clear shift in India’s approach to rooftop solar.. In many cases, the emphasis is on solar readiness: reserving shadow-free roof area, planning electrical infrastructure, and ensuring that buildings can integrate solar systems later. However, national codes do not become effective automatically. Their impact depends on how states adopt them, translate them into local building rules, and enforce them through permits and occupancy approvals. That implementation story is the focus of the next blog.