Two different credits can be claimed on IRS Form 5695 Residential Energy Credits, the nonbusiness energy property credit and the residential energy efficient property credit. 

The nonbusiness energy property credit is only available to taxpayers who own the home they have improved. Section 25C(c)(1)(A) of the U.S. Code states that any improvement must be "installed in or on a dwelling unit located in the United States and owned and used by the taxpayer as the taxpayer's principal residence." Similarly, the instructions define qualifying improvements as those "installed on or in your main home that you owned." 

The U.S. Code and the instructions for Form 5695 do not clearly state whether home ownership is necessary for the residential energy efficient property credit. However, other IRS publications often refer to homeowners when discussing the credit. 

Note: The nonbusiness energy property credit is only available for existing homes. The residential energy efficient property credit is available for both existing homes and homes being constructed.

For a list of improvements that qualify for the credits, see the Energy Star website Federal Tax Credits for Consumer Energy Efficiency.