We have what is called a shading coefficient (SC), which is a measure of how much heat a window and screen fabric let into a room. We also have a better measure called the Solar Heat Gain Coefficient (SHGC), which is better because it measures more accurately how much heat is making it into the room through all parts of the complete window opening system - glass, frame assembly, plus fabric. It also accounts for heat that is absorbed and is either re-radiated into the room or convected away to the outside. (Side note - this is why mini blinds are so horrible - they are like radiators in your hot windows.)
So, as a consumer of solar roller shades, you must be sure you are comparing the proper coefficients when comparing vendors and fabrics. The SC measure will provide a better number, if compared to an SHCG measure, but may not be a better product. So, make sure you are comparing apples to apples, else you might not be getting the comparatively better product. Whichever measuring system you are considering, the lower the number, the better job your window and solar roller shade system will do controlling the heat. By being an informed consumer, you will be an empowered and ultimately happier consumer - which is our goal for you - whether you buy from us or not.
We would love to help you with your solar roller shade project. Please kindly spend some time with our online roller shade calculator for an idea of what your project may cost.