Clerestory windows, like roof windows or skylights, can cause substantially greater overheating and heat loss than standard windows. Clerestory windows might be a disadvantage. Even with the greatest glazing, they can be a source of energy waste and cause unwanted glare and overheating. They require more energy to operate and are not as efficient as intended. The main disadvantage of clerestory windows is their impact on room temperature. They tend to transfer heat into the building rapidly, which could cause interior spaces to feel hot or cold depending on how they are used. Although glass blocks out solar radiation, it allows heat to pass through it and enter the building. This can lead to heated rooms in the summer and cold rooms in the winter. Clerestory windows are also very expensive. Not only do they usually require special construction techniques that increase the cost of buildings, but they also consume much energy. Modern versions may use fluorescent tubes instead of natural light to reduce costs and energy consumption even further. Finally, clerestory windows make buildings look old-fashioned. Because they are so unusual, they suggest that you are building some kind of historic structure, which many modern buildings don't need or want. In conclusion, clerestory windows are very inefficient because they allow heat to pass through them.