Built environment is a problematic issue from an energy use perspective because an important part of total energy consumption in countries is usually caused by existing buildings. Current buildings stock constructed before 2000 in Turkey is mostly thermally poor and current standards related to energy efficiency in buildings are relatively not enough when compared with international examples. In this research, impacts of various energy efficient measures on heating for an existing detached two-storey house located in cold climate, Eskisehir-Turkey are analyzed to find possible energy saving rate by using DesignBuilder and EnergyPlus software. Firstly, energy consumption profile for base case is simulated then, effect of defined energy efficient measures on total heating energy consumption is investigated. Lastly, life cycle approach is applied to make an economic analysis and estimating payback period for energy efficient measures, As a result, the highest energy saving (37%) for heating was obtained by the application of thermal insulation on external wall, floor and ground floor and replacement of current windows. In addition, the payback period of energy efficient measures are more than 10 years; thus, the government should support energy efficient retrofitting of existing buildings in Turkey.