I have a question about 26USC25Dd2 as it applies to 26USC25Da1: in it it says "used as a residence by the taxpayer." I am looking for an attorney or anyone who can answer my question: is "residence" where I live? I live in my mom's house (she owns it) and I want to buy and own solar panels on her house and I get the 30% tax credit for 2016. I have plenty of federal tax to offset and she does not. If you look at 26USC25Dd3, it refers to 26USC121, but 26USC25Dd2 does not. "26USC25D" & "26USC121" can be Google'd, & law.cornell.edu has them one click away for free, so I won't put links myself.