The energy consumption of the building sector in Algeria represents the largest part of the energy produced in the country. Action to reduce the impact of this sector on the economy and the environment must be taken. The use of thermal insulation to reduce the energy needs of the building sector represents an effective and sustainable solution.The objective of our work is to conduct a study using the TRNSYS 17 software on the influence of the use of thermal insulation in different climates in Algeria. A typical apartment is chosen to run the calculations under three different climates of Algeria. The simulation results obtained for the city of Annaba show that the use of rock wool, cork, expanded polystyrene and airgel insulation allows a reduction of 42.81%, 43.08%, 43.31% and 50.90% respectively. While for the city of Setif the reduction obtained is 34.15%, 34.70%, 35.13% and 52.25% respectively for the same insulation. For the city of Biskra the reduction is 32.07%, 32.28%, 32.45% and 38.72% respectively for the same insulation. The improvement of the thermal performance of the structure and the glazed surfaces according to the Passivhaus standard allows a significant reduction of heating and air conditioning needs estimated at 72, 78.21 and 65.21% respectively for the cities of Annaba, Setif and Biskra. A low energy consumption building is obtained for the city of Annaba and Setif.