Welcome to 139 Skillings Street, an updated duplex situated on a nearly one-half-acre lot featuring a fully fenced backyard--a rare find for a multifamily property in South Portland. The private backyard offers space for entertaining, gardening, relaxing, or enjoying time with pets. Ideal for both owner-occupants and investors, this well-maintained duplex offers comfortable living with excellent rental income potential. The first-floor apartment features three bedrooms, one bath, a living room, and an eat-in kitchen with granite countertops, new high-end stainless steel appliances, ceramic tile flooring, new luxury vinyl plank flooring, fresh paint, and a private rear deck. The second-floor apartment offers two bedrooms, one bath, abundant natural light, hardwood floors, an eat-in kitchen with granite countertops, ceramic tile flooring, fresh paint, and direct stairway access to the backyard. Additional features include off-street parking for four to six vehicles, a storage shed, a dry concrete basement with washer/dryer hookups, and a spacious stand-up attic offering abundant storage. Two completely separate heating and domestic hot water systems set this duplex apart. The property can be heated by either a two-year-old Viessmann high-efficiency wall-mounted boiler or a premium European-designed wood pellet boiler with a 7,000-pound pellet hopper that offers exceptionally economical heating. Both systems provide independent thermostat control for each apartment. Conveniently located just minutes from I-295, downtown Portland, area beaches, the Greenbelt Trail, shopping, restaurants, schools, and public transportation, this property offers an outstanding opportunity for owner-occupancy, rental income, or long-term investment, complemented by a private backyard that provides a welcome retreat.