Updated: May 18, 2020
Thermocol or EPS sheets are in fact an excellent thermal insulator for the Indian climate. They are lightweight and affordable (making them easy to install), with a high insulation value.
I would also like to set the record straight, insulation with EPS is a smart choice to make even if you don’t use air conditioning (AC).You see, insulation maintains a comfortable interior environment. When you insulate, it DOES NOT LET THE HEAT IN during summers, because the source of heat is the exterior environment.
Back in the olden days, homes used to be built with thick mud walls. These walls, due to their thermal mass (http://www.yourhome.gov.au/passive-design/thermal-mass ) would act as very good heat stoppers. These homes used to be very comfortable, and the comfort factor was increased by hanging wet chiks/ jute mats/ curtains on all windows and doors. This method of utilizing "thermal inertia" to stop the heat has become expensive because of the large quantity of expensive building materials and the equally expensive labour cost to assemble the same. Even the space consumed in thick walls has a very high cost these days and hence the advent of "Insulation" as an additional building layer to stop the heat. Of course, if you let the warm air indoors by leaving your windows and doors completely open, insulation will not work very efficiently for you, regardless of whether it is a mud house or a modern home with EPS insulation.
An added benefit of insulation with EPS is, if you choose the right products, a phenomenon called thermal bridging will not occur. Thermal bridging refers to heat seeping in or out through small uninsulated regions, such as the gap between two insulation panels, or the uninsulated areas near fixtures. This not only decreases the efficiency of insulation, but also reduces the strength of the building. The reason is that buildings are composite structures made of materials that expand or contract due when exposed to heat or the cold respectively. The variation in daily temperatures, as well as the difference between day and night, is sufficient to cause this thermal expansion/contraction. What happens when something that is not very flexible expands or contracts too many times? It cracks.
So EPS insulation increases the life of the structure as well as making the interiors comfortable, and you need it for your home regardless of whether you use AC or not. Caution to novice insulation users : PLEASE USE CERTIFIED QUALITY EPS FROM A REPUTED MANUFACTURER . MINIMUM 24 KGS/M3 SHEETS FOR ROOF OVERDECK INSULATION AND SELF EXTINGUISHING GRADE OF EPS (MINIMUM 18 KGS/M3) FOR WALL INSULATION. PLEASE DON'T GO FOR NEIGHBOURING STATIONERY SHOP THERMOCOL. For more details on thermal insulation, check out our website Building insulation Home | Reliable Building Solutions India