Humm, I can’t tell you much without seeing the version of the EO you purchased, Valerie, but one reason why they could have said that is that the EO you bought is a cold-pressed orange EO which can cause photosensitivity after sun exposure. Cold-pressed citrus oils are known to do that, as well as a few others. Here’s a great post on this topic. What you can do is use it for flavoring things, cleaning, diffusing, or in your skin care products during the winter months when you won’t get as much sun exposure and purchase a steam-distilled orange EO to use during the summer months. Hope this helps!
You need a cool-air diffuser. These diffusers usually require a small amount of distilled water to be added along with essential oils. Note: Cold air diffusers ranges vary, with most around 250 feet. So if you are trying to diffuse your bedroom and living room, most likely you will need two diffusers. This one is my favorite for the money and size/features.