Energy Efficient WindowsVolume 1 · Issue 1 · June 2026
Windows That Keep the Heat Out
In hot India the window is the weakest point in the envelope — most of the heat that drives up the AC bill walks straight in through the glass. This is the 11-guide energy library: cutting solar gain, insulation and sealing, the numbers that matter, energy ratings, green-building credits and low-carbon, net-zero windows — grounded in the Eco-Niwas Samhita envelope code.
Energy Efficient Windows Explained: The Whole-System Guide for Indian Homes
The system-level pillar on energy-efficient windows in India: U-value, SHGC and VLT explained, the honest hot-India reframe toward low SHGC and shading, an assembly-tier comparison table, a five-zone climate cheat sheet, and a homeowner decision framework.
Read itKeeping the heat out
Heat gain, shading, insulation
By climate zone02Best Windows for Indian Climate: A Zone-by-Zone Selector
There is no single best window for India. This zone-by-zone decision matrix pairs window type, frame material, glass, and shading to hot-dry, coastal, composite, temperate, and hill climates, including the honest cold-zone flip.
Heat-gain playbook03Reducing Heat Gain Through Windows in India (2026): The Ranked Playbook
The rupee-ranked playbook to cut window heat in hot India: orientation, external shading first, low-SHGC Low-E glass, solar-control film for single glazing, blinds last, and the night flush, anchored on SHGC from 0.82 down to 0.25.
Shading04Window Shading Strategies for Indian Homes
External shading stops solar heat before it reaches the glass and is 5 to 10 times more effective than internal blinds. A device catalogue with overhang projection rules and sun-path geometry, mapped to south, east, west and north windows in India.
Solar gain05Solar Heat Gain and Windows in India: The Science of SHGC
Understand the science of solar heat gain through windows in India: what SHGC means, the greenhouse effect in glass, sun-path by orientation, why west is worst, and how Low-E cuts heat while keeping daylight.
Insulation06Window Insulation Guide for Indian Homes
The insulation mechanism behind a good window: glazing cavity (12 to 16 mm air gap, argon, warm-edge spacer), frame and thermal break, and air sealing — with a U-value ladder and the honest hot-India priority order.
Reading the numbers
Metrics, labels and ratings
Thermal metrics07Thermal Performance of Windows: Reading the Spec Sheet
Understand the window spec sheet: U-value, SHGC, VLT, LSG, Air Leakage and Condensation Resistance explained with numbers, the four heat paths, thermal bridging, condensation, an assembly table, and why SHGC beats U-value in hot India.
Energy ratings08Window Energy Ratings Explained for Indian Homes
How to read a window's energy rating in India: the five numbers on an NFRC label, ENERGY STAR climate zones, and the honest reality that there is no consumer window star-label here — so verify the manufacturer's tested SHGC and U-value against an NFRC or EN report.
Green, net-zero and low-carbon
Credits, net-zero and embodied carbon
Green building09Green Building Window Design for India
The windows-only green-building scorecard for India: which window decision earns which IGBC, GRIHA or LEED credit and the thresholds (IGBC SHGC 0.45, GRIHA 0.25, daylit-area and NBC 10 per cent openable), with the Eco-Niwas Samhita envelope baseline beneath the voluntary certs.
Net-zero10Net-Zero Home Windows in India
How windows decide whether a net-zero home works: shrink the cooling load so a modest rooftop PV array can offset it. The Passive House spec, the honest hot-India reframe, and a net-zero window priority table by climate zone.
Embodied carbon11Sustainable Window Materials in India: The Embodied-Carbon and Lifecycle Lens
Which window frame is genuinely sustainable in India? We rank wood, uPVC and aluminium by embodied carbon, recyclability and end-of-life — and explain why lifetime operational carbon usually dwarfs the factory footprint.