In general

The term “residential energy property expenditures” means expenditures made by the taxpayer for qualified energy property which is—

(A) installed on or in connection with a dwelling unit located in the United States and used as a residence by the taxpayer, and

(B) originally placed in service by the taxpayer.

Such term includes expenditures for labor costs properly allocable to the onsite preparation, assembly, or original installation of the property.