Source: Intelligent Building Today
As I have written before about radiant barriers:
Most building materials have high emissivities, i.e.: roofing shingles, plywood, OSB, etc. and will tend to radiate the heat they generate during those hot summer days into the cooler areas of the building easily. Installing radiant barriers and IRCCs places a low “e” surface just below (or to the underside of) the roof to retard this heat influx, redirecting it back through the roof and out of the structure. The result is drastically cooler attic spaces (5-20 degrees F or more), which increase the operating efficiency of the standard r-value insulation in the structure, resulting in reasonable savings on air conditioning bills (5-15% or more).
Every structure is different. As well as many factors are involved in the total heat flow of the system. It will cause every building to experience different results. However, with a material cost of just pennies per square foot. Then an installed cost of $0.50-$1.00 per square foot for IRCCs and $1.00-$2.00 per square foot for radiant barriers. So the ROI can be much more rapid than other insulation technologies.
As well, green buildings can reduce emissions by up to and more than 35%. Greener buildings can also reduce energy from 30-60% In net zero buildings its 100%.