W. Va. Code § 11-13Z-2: Restrictions.

In order to receive the credit for a solar energy system on residential property, the system must use solar energy to:

(1) Generate electricity;

(2) Heat or cool a structure; or

(3) Provide hot water for use in the structure or to provide solar process heat: Provided, That this does not include a swimming pool, hot tub or any other energy storage medium that has a function other than storage: Provided, however, That the system used to provide hot water must derive at least fifty percent of its energy to heat or cool from the sun.