Living in the Caribbean is total Paradise and you want to make sure that your goods are well protected from the intense sunrays.
In your homes, you have beautiful furniture, pillows, paintings, rugs that you want to keep intact as long as possible.
One way to do it is by choosing the right fabric.
I recommend a high quality Indoor/Outdoor fabric for your indoor furniture and for the outdoor furniture that has full sun exposure; you need a reputable Outdoor fabric.
As for window treatment, the face fabric needs to be protected with a sun resistant drapery lining unless you prefer light, breezy sheer panels. In that case, a mix of polyester would be more durable than 100% cotton.