According to the Energy Conservation Code, the maximum glazed area is calculated from a percentage of the __________ gross area when building a 4-story residential building.

The maximum glazed area for a building is indeed calculated based on a percentage of the floors' gross area. This approach is in line with the principles set out in the California Energy Conservation Code, which aims to promote energy efficiency in buildings by regulating how much glass or glazing area can be incorporated in the facade relative to the overall footprint of the building.

Using the floor area as the basis for calculating allowable glazing helps ensure that buildings are designed to maximize natural light while minimizing energy loss associated with heating and cooling. Since windows can significantly affect a building’s energy performance, it's crucial to control their size in relation to the overall floor area, especially in multi-story residential buildings. This regulation supports the goal of reducing energy consumption and enhancing the sustainability of construction practices.

In contrast, calculating the maximum glazed area from exterior walls, interior walls, or the roof would not accurately reflect how glazing affects a building's energy efficiency. Those surfaces do not directly determine the potential energy exchange that occurs through the building's windows relative to the overall living or usable space of the building, which is why the floor area is the correct metric.