I was in a local business a few months ago that had a very large south-facing plate glass window. The place should have been cooking hot, but it wasn’t. Then I noticed the window had a kind of reflective film on it that also softened the glare and created privacy.
Now I’ve had the local auto-window tint place put that bronze film on several units with south and west windows. It has made a huge difference. The film creates privacy like one-way glass, so tenants leave the curtains open and don’t use as much electricity, or A/C.
It’s a little pricey and I’ve heard that you can do it yourself, but we just like to get 'er done. Last summer our office was choking hot, this year tolerable with the windows bronzed.