The researchers studied how solar energy can make buildings in Algeria use little to no extra energy. They looked at a solar house in Boussaâda in different Algerian climates. With special walls and windows, the house used less heat, about 2 times less in some cities. If the building was better insulated, even more energy could be saved. By using active solar systems, the house could get all its energy from the sun – even for things like heating water and running electronics. This means the house can be completely energy-efficient in different Algerian climates.