The plan for the Habitat for Humanity homes in South Portland City of South Portland

SOUTH PORTLAND — The Planning Board on Wednesday unanimously approved an eight-home affordable housing project proposed by Habitat for Humanity of Greater Portland and the South Portland Housing Authority’s development staff.

The energy-efficient, single-family homes will be built off Sunset Avenue, which is off outer Main Street/Route 1 and Union Street, in the Thornton Heights neighborhood. A ninth lot will be donated to the city to remain open space, said Laura Duplissis, Habitat spokeswoman.

The houses will be sold through Habitat with interest- and principal-free financing. Selected families will pay no more than 30 percent of their incomes on mortgage payments, taxes and insurance. Selling prices will be based on the appraisal of each house at the time of sale, Duplissis said.

The project will be designed by Acorn Engineering of Portland. Construction of the first home will begin this spring, for delivery starting next fall. Habitat will begin holding informational meetings and taking applications in the next few months.

Habitat recently completed a 13-home community in Scarborough. Each of those 3- to 4-bedroom homes are energy-efficient with total utility costs of approximately $120 per month.