Green Building Window Compliance Tool
Pre-check your window and glazing design against the Eco-Niwas Samhita (ENS 2018) residential envelope code. Enter your WWR, glass VLT, SHGC and U-value to see an instant pass / needs-work verdict with fixes.
Your glazing design
VLT = visible light transmittance, SHGC = solar heat gain coefficient. The RETV check uses a simplified proxy — it is an indicative pre-check, not a formal ENS compliance report. Verify with a professional and your local bye-law.
ENS pre-check verdict
PASS
0 / 3 checks pass · WWR 35%
RETV proxy
4.7 W/m²
limit 15
VLT floor
0.20
0.30 – 0.40
Your SHGC
0.27
lower is cooler
U-value cap
3.0
for this zone
RETV proxy vs ENS limit
Per-check breakdown
Daylight — VLT floor for your WWR
Your value: VLT 0.45 · Required: ≥ 0.20 (0.30 – 0.40)
Daylight transmittance is adequate.
Heat gain — RETV proxy
Your value: 4.7 W/m² · Required: ≤ 15 W/m²
Envelope heat gain is within the indicative cap.
Conduction — assembly U-value
Your value: 2.6 W/m²K · Required: ≤ 3.0 W/m²K
U-value is suitable for this climate zone.
Indicative pre-check using ENS-derived rules and a simplified RETV proxy (India 2026). This is not a formal Eco-Niwas Samhita compliance report — confirm with a green-building professional and your local building bye-law before submission.
Design code-ready windows
DesignAI specs glazing — WWR, SHGC and shading — to hit Eco-Niwas Samhita targets for your climate.
Related Guides — Deep-dive reading
Energy-Efficient Facades in India: How the Building Skin Cuts Your Cooling, Heating & Lighting Bills
How a building facade drives cooling, heating and lighting energy in India, the three levers of solar-heat-gain control, insulation and daylighting, U-value, SHGC, VLT and WWR in plain terms, ECBC and Eco-Niwas expectations, and real Indian green buildings.
Building FacadesGreen Building Window Design for India
The fenestration scorecard — exactly which window decision earns which IGBC, GRIHA or LEED credit, and the numeric thresholds to hit
Windows & GlazingGreen Building Window Standards in India
The mandatory envelope code (ENS 2018 and ECBC 2017) your windows must legally meet — RETV, the WWR-VLT ladder, U-value and the compliance paperwork — and how it differs from the optional green-rating scorecard.
Windows & GlazingRelated Tools — You may also find these useful
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Compute WWR percent and check it against Eco-Niwas Samhita VLT and RETV limits and climate.
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Estimate a room's average daylight factor, daylit depth and natural-light adequacy from glazing and VLT.
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Score your home 0 to 100 on daylight, ventilation, thermal and acoustic comfort and find the weak link.
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