Will sun exposure damage my speakers?

While ordinary window glass absorbs a fair amount of uv radiation, enough gets through to be of concern. Many plastic resins are not uv stable, so the amount of exposure should be considered. Are you getting direct sun or indirect light? If only a little direct sun hits them during the day, I wouldn't worry too much. Too much sun exposure can also bleach wood veneers over a period of time also.

SPF 45.

Yes, it will. It will cause premature failure of foam surrounds and fade parts of the cabinets that are exposed to the light.

Having said that, i'm in the same situation with one of my systems. As such, i treat the cabinets with Lemon oil, which keeps them from drying up and helps retain their "rich" wood finish, and i rotate the speakers. This keeps the "fade" relatively consistent between the two, yet does nothing for the other side of the cabinet that isn't exposed to light. Sean
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Yes, absolutely! During the course of the year my REVEL sub gets quite some sunshine and I cover it with a towel during that time and days. Whatever rubber is used for the cones: it doesn't like the sun at all.
Good luck!