The openness percentage refers to how tight the weave is on the solar shade. The higher the percentage, the more light will filter through into the room and the greater the view to the outside (but the less it will block UV rays). The lower the percentage, the less light will filter through into the room and the less of a view to the outside (but the more the shade will block UV rays). For example, solar blinds with a 10% openness will block 90% of UV rays, while solar shades with 1% openness will block 99% of UV rays. Click here to see the various openness percentage options.
You may find it useful to order free samples of solar blinds with different openness percentages so you can see the differences for yourself.