Can I deduct the cost of a new ceiling fan purchased for my home office if I am self employed and work exclusively from within that space?

Yes. You can deduct the full price of the ceiling fan in your home office work space.

Improvements that impact you work space and other areas of your home (such as a new cable line) are apportioned to the percentage of your home used for work.  

For more information, follow this link: Schedule C Instructions