I usually use 10% and in a dark color the darker they are the better the view out of them . I use Steves blinds often with no issues and good pricing. Just follow the directions for measuring often the shipping is free. Yes they really do cut the heat and laso the damaging UV rays to save fading of upholstery and wood floors. I have been using solar shades for clients for more than 20 yrs.

Thank you so much for your replies! This is so helpful!

I recently installed them along with UVA blocking film on the window.

I wanted to preserve the view and not feel that I was in a tomb when they were down so mine aren't massively opaque and the film is not apparent at all from exterior or interior.

I have a very strong Eastern exposure and without the shades/film the morning would be unbearable even with the A/C running full blast. I am in Los Angeles so even in the WINTER if there was strong sun and moderate temperatures, it would heat up like a greenhouse almost.

With the installation, temperatures remain moderate even when the direct sun is pouring in and based on tentative comparisons to prior electric bills in the same months, I appear to also be saving some money on energy costs.

I installed the film because I wanted to protect my stuff from as much sun damage as possible as some of my stuff had "fried" in the direct sun prior to the remodel.

I have the 3% in my desert home & 10% in my beach home ( on a large window to prevent fading, heat not an issue ). The do help with heat in the desert.

Thank you all!