On a sunny day, daylight is 200 times more intense than the illumination from artificial lights in a well-lit room. Fluorescent light is a concern because it yields high amounts of ultraviolet light in comparison to other artificial light sources. The most immediate danger of incandescent light is heat build-up. First and foremost, beware of daylight. Direct sunlight is the worst culprit, but even northlight or daylight filtered through ultraviolet shields will cause more photochemical deterioration than unshielded fluorescent lights.
Daylight is that intense.
The only defense against daylight is to block it out. Many local history museums cannot simply block up all their windows because they occupy historic buildings. As a further step, close all blinds, drapes, or shades when the museum is closed or when a particular room is not in use. If you have police patrols that prefer to see in windows, make covers for cases, furniture, and mannequins to block sunlight when the museum is not in use. Cloth covers should be made of white sheets, white flannel, or unbleached muslin to avoid heat build-up.