Thermal Insulation

Thermal insulation in buildings is the use of materials and systems to reduce heat transfer between building interior and exterior environment. Properly designed thermal insulation reduces HVAC energy consumption (heating in cold climates, cooling in hot climates), improves occupant comfort, and reduces condensation. Indian Standard: IS 3346:1998 (thermal insulation) + ECBC 2017 (Energy Conservation Building Code) for energy-efficiency requirements. Major Indian thermal insulation suppliers: Rockwool India, Owens Corning India, ARMACELL India.

Main thermal insulation categories: (1) Mineral wool — rockwool or glass wool; thermal conductivity k = 0.035-0.045 W/mK; fire-resistant; used for ceilings, walls, equipment insulation. (2) Polystyrene (EPS, XPS) — k = 0.030-0.040 W/mK; rigid boards; used for roof and wall insulation. (3) Polyurethane foam — k = 0.022-0.028 W/mK; spray-applied or boards; highest insulation per thickness. (4) Reflective foil — radiant barrier; effective in tropical climates. (5) Cellulose — recycled paper-based; used in eco-construction.

Applications in Indian buildings: (a) Roof insulation — most-impactful in hot climates; typical 50-100 mm rockwool or PUR foam. ECBC 2017 mandates roof U-value < 0.4 W/m²K for cooling-dominated regions. (b) Wall insulation — exterior wall insulation gaining popularity; cavity wall insulation in modern apartments. (c) Floor insulation — for upper floors with unconditioned space below. (d) HVAC duct insulation — preventing condensation and energy loss. (e) Equipment insulation — pipes, tanks, machinery. The most-overlooked aspect of Indian thermal insulation: roof — flat RCC roofs in tropical climates can reach surface temperatures of 60-70°C in summer. Without insulation, this heat transfers to the slab and into the room below. Adding 50 mm rockwool on top of waterproofing reduces room temperature by 4-6°C and HVAC consumption by 25-35% — paying back the insulation cost in 3-5 years through reduced electricity bills.