Would like to purchase and install some window film so that I might be able
to lower my air conditioning usage.
I've done some research online and some sites recommend spectral selective
films with a Luminous Efficacy Constant over 1.0. Other sites recommend
films with a Light-to-Solar-Gain ratio exceeding 1.0. (I have no idea
whether LEC and LSG are the same thing...)

I went to the local Lowe's and Home Depot stores but they only carry Gila
Films products and none of them has any specs on the boxes. Are there any
online sites that sell window films and post specs for their products?
--
Tiziano