I believe the claim of 95% UV reduction. That's necessary to protect the covering itself. The coverings lacking a UV blocker are destroyed in short order. The only disadvantage I've heard about is bumblebees may not do as well under some coverings due to light exclusion that they need to navigate. I don't think lack of UV will affect plants. But greenhouse plants still might need some hardening off when going outside. No direct IR simply means as you suggest that it has been diffused. This might reduce heat stress on some plants but I've not seen much damage under clear polycarbonate with 90% transmission. Max heat gain by day will likely translate to max heat loss at night. In my climate two layers inflated of woven poly reduces both heat gain by day and heat loss at night. A plus here but we have lots of sunny warm days all winter..

We replaced the regular fiberglass window screens with solar shade fabric which we found at L's Home Improvement. There are other benefits than just protecting fabrics from fading. They also add privacy to your home. During the day no one can see in unless they press their face against the screens. At night only silhouettes if back lit. Something we didn't expect but are happy with is that grasshoppers can not eat through the thicker fiber these screens are made with. Not sure that's a problem in the city, but we live in the country where every couple years or so we are over run by grasshoppers. I would love to be a kid at heart again, but lately it's been crazy around here. I'm working on getting there again though.

Film doesn't need to stick directly to the glass. It is filtering the UVA/UVB rays installed as is. Depends on the film as to how long it will last.

Ok, I'll nix the fabric panel options. Leaning toward new lined woven romans. Tibb & Bpahome - I'll read up on the window films but I think it would be very hard to get right on a large space. Bumps or creases would really bother me. Rose - Well you're hip and my grammy wouldn't use those either. :) I can come up with some doozies when tired. I find my eye goes often to the wide span of white 2" blinds in my LR and I don't care for it, but that ended up being the best/most practical option for us in their. White woven - hmm.. you mean like bleached? I didn't realize they made shutters for patio doors until I was searching window treatments. I even found some magnetic blind options I didn't know they made. I was thinking our basement door, but the reviews were saying the magnet wasn't strong enough to raise and lower without pulling down. Nice idea though. Tina - The blinds are from Home Depot, but I know they made separate liners (saw at Lowes) you can attach to existing shades. I never got around to buying them before because I wanted the light not realizing my stuff is fading. All our windows are actually low-e. They're Anderson and whatever ones they are do nothing for sun protections. :( If we ever replace (I'm hoping move) I'll be researching the heck out of windows.