In the summer, due to the sunlight, the indoor air is constantly going up, and the temperature in the attic is generally higher than the downstairs. At this time, if an exhaust fan is installed at the top of the attic, the heat will be continuously drained, the whole room will cool down, and the electricity cost of installing the air conditioner will be saved. Not only that, the attic ventilation keeps helping to eliminate the harmful effects of condensation build-up, which can lead to decay, mold and mildew. Nowadays, the combination of attic fans and solar technology perfectly solves the problem of energy saving and ventilation. Under the effect of low-cost solar energy, fresh air is kept circulating through the attic space.