...lol.. looking for a loop hole to double dip hey...
Principal or PRIMARY is kind of the interpretation. Putting "games" aside, one always has a primary residence over "the other". I believe that once you put one (solar) on your primary, that's it until you move to another. Then I believe you can claim solar on your "new" location home. Assuming you are speaking about the Federal tax credit, and not some states credit.
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william fitch
Owner
www.WeAreSolar.com------------------------------