The 45L tax credit is a tax credit available to builders and landlords of energy-efficient new homes and apartments in the United States.

The credit is for $2,000 for each new energy-efficient home and $1,000 for each new energy-efficient apartment. To qualify for the credit, the home or apartment must be built to meet certain energy-efficiency standards set by the U.S. Department of Energy (DOE) and the Internal Revenue Service (IRS).

These standards include requirements for insulation, windows, doors, heating, cooling, and hot water systems, as well as other energy-efficient features. The credit is claimed on the tax return on the year the home was built or acquired.