An exemplary construction project developed in a commune close to Constanta, Romania, aims to build wooden houses for families with low income. The study focuses on their energy performance, aiming to determine simple technical solutions for the improvement of energy efficiency. The original house is a duplex ground floor building. The energy assessment was performed in accordance with the Romanian methodology for the original house, for the reference one and for a variant of the original house whose ground floor is insulated. The study showed that appropriate insulation of the ground floor which covers 30% of the thermal envelope area results in a heating energy saving of 17%. Furthermore, the original horizontal duplex was compared to its similar vertical version (ground floor and one storey) which is more compact, at the same heated volume and the same heated area. The reference vertical version saves 3% of heating energy.